Article

Ancestry, Plasmodium cynomolgi prevalence and rhesus macaque admixture in cynomolgus macaques ( Macaca fascicularis ) bred for export in Chinese breeding farms

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Background: Most cynomolgus macaques (Macaca fascicularis) used in the United States as animal models are imported from Chinese breeding farms without documented ancestry. Cynomolgus macaques with varying rhesus macaque ancestry proportions may exhibit differences, such as susceptibility to malaria, that affect their suitability as a research model. Methods: DNA of 400 cynomolgus macaques from 10 Chinese breeding farms was genotyped to characterize their regional origin and rhesus ancestry proportion. A nested PCR assay was used to detect Plasmodium cynomolgi infection in sampled individuals. Results: All populations exhibited high levels of genetic heterogeneity and low levels of inbreeding and genetic subdivision. Almost all individuals exhibited an Indochinese origin and a rhesus ancestry proportion of 5%-48%. The incidence of P. cynomolgi infection in cynomolgus macaques is strongly associated with proportion of rhesus ancestry. Conclusions: The varying amount of rhesus ancestry in cynomolgus macaques underscores the importance of monitoring their genetic similarity in malaria research.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... Macaca mulatta (rhesus macaque) and M. fascicularis (long-tailed macaque) are the two most commonly used non-human primate models in pharmaceutical, toxicological, and other commercial research. [1][2][3] The genetic background of non-human primate models can substantially influence research outcomes 1 ; Zhou et al. (2013) 4 . For instance, Chinese and Indian M. mulatta exhibit disparities in disease infection, disease progression, and immunological response [5][6][7][8] ; Zhou et al.,4 that is attributed to their significant genetic differences. ...
... 12 In addition to promoting the reduction in the number of animals used for experimentation following the principles of the 3Rs (replacement, reduction, and refinement 13 ), genetic characterization also helps minimize errors in interpreting experimental outcomes. 3,14 Over the past decade, M. fascicularis aurea (Burmese long-tailed macaque), one of the ten subspecies of M. fascicularis, 15 has received much attention after the discovery of their stone tool-use behaviors at Laem Son National Park (9°35'N, 98°28'E), southwestern ...
... Comparable strategies are now achievable that utilize inter-fluidic PCR chips to amplify up to 96 SNP markers at once and quickly discover population admixture in macaques. 3,49 ...
Article
Background This study examined the population structure of Macaca fascicularis aurea and their genetic relationships with M. f. fascicularis and M. mulatta. Methods The study analyzed 868 RADseq-derived SNPs from samples representing the entire distribution range of M. f. aurea, including their inter- and intraspecific hybrid zones. Results The study supports a M. mulatta/Indochinese M. f. fascicularis, Sundaic M. f. fascicularis, and M. f. aurea trichotomy; M. f. aurea was genetically distinct from both forms of M. f. fascicularis and M. mulatta. Hybridization between M. f. aurea and M. f. fascicularis occurred in two directions: south-north (8°25′ to 15°56′) and west-east (98°28′ to 99°02′). Low levels of M. mulatta introgression were also detected in M. f. aurea. Conclusion This study showcases a complicated scenario of genetic relationships between the M. fascicularis subspecies and between M. fascicularis and M. mulatta and underscores the importance of these taxa's population structure and genetic relationships for biomedical research.
... Knowledge of the ABO blood type of each primate in a research colony is essential for successful procedures requiring transplantation or transfusion (Socha, Marboe, Michler, Rose, & Moor-Jankowski, 1987). Additionally, it is known that rhesus and cynomolgus macaques, the two NHP species most commonly used in biomedical research, express differential reactions to disease and that introgression between the two macaque species can affect disease status (Zhang et al., 2017). In the light of recent research that suggests a broader zone of intergradation between the two species (Bunlungsup, Kanthaswamy, et al., 2017), the goal of this study was to characterize the distribution and population genetics of ABO blood groups in the rhesus-cynomolgus macaque hybrid zone encompassing Myanmar, Laos, Thailand, Cambodia and Vietnam. ...
... The blood group distributions were shown to differ among all zones and by mor- et al., 2013;Yan et al., 2011), their genetic structure more closely resembles that of insular cynomolgus macaques than that of rhesus macaques. This is congruent with genomic research of the two species that has found signatures of cynomolgus macaque genetic introgression into the Chinese rhesus macaques (Bonhomme et al., 2009;Bunlungsup, Kanthaswamy, et al., 2017;Kanthaswamy et al., 2010;Satkoski Trask et al., 2013;Stevison & Kohn, 2009;Tosi et al., 2002;Zhang et al., 2017). and use of laboratory animals. ...
Article
Knowledge of the macaque ABO blood group system has been critical in the development of nonhuman primates (NHPs) as a translational model. Serving not only as a useful homologue of the disease‐linked ABO system in humans, macaque ABO blood groups must be typed in colonies prior to performing experimental procedures requiring blood transfusion or transplantation. While the rates of blood type incompatibility and the distributions of A, B and AB blood groups are known in large samples of rhesus (Macaca mulatta) and cynomolgus (M. fascicularis) macaques, there is a dearth of blood type data from macaque populations occupying the rhesus‐cynomolgus hybrid zone in Southeast Asia. Using molecular phenotyping, we profiled ABO blood group distributions of 232 macaques from 10 populations in the hybrid zone and compared them to pure blood populations of the two species. We found that while these distributions are significantly different in most populations, there was a lack of differentiation between the hybrid and cynomolgus macaques as well as between the Thai and neighbouring populations. This supports a more expansive model of hybridization between rhesus and cynomolgus macaques than often proposed and highlights the increased need for consideration of population genetic structure in biomedical studies that employ macaques as animal models. Additionally, we report an enrichment of indeterminate blood types in the hybrid populations.
... No. 3 references the Suzhou/Kunming samples, cited at Kunming on the map (Suzhou is in the eastern Chinese province of Jiangsu), which were obtained from the California National Primate Research Center (CNPRC) genotypes for at least 90% of all samples and samples providing genotypes for at least 90% of all SNPs were employed in further analysis.2.3 | Population genetic parameters and genetic structure analysisGenotypes of all population samples were tested for their fit toHardy- 2000) was used to characterize the admixture between the two species. To estimate the proportion of genetic admixture, all rhesus and long-tailed data were analyzed based on the admixture panel of 48 SNPs(Zhang et al., 2017) assuming an admixture model. A total of 500,000 iterations of MCMC were run, and 20% (100,000 iterations) of data were discarded as burnin. ...
... The number of population clusters (K) was set between 2 and 15 (2 ≤ K ≤ 15) and run for five iterations for each value of K. To calculate the highest probability of the true number of clusters, a deltaK (ΔK) analysis based on the second order derivative of the change in variance of the log probability between successive K values(Evanno, Regnaut, & Goudet, 2005) was performed over five iterations. Genetic differentiation among long-tailed populations was assessed using only the long-tailed macaque genotypes based on the 48 SNP ancestry panel(Zhang et al., 2017). All parameters were set as for the analysis described above using the admixture panel, and ΔK was calculated to find the value of K with the highest probability.All 96 SNPs together with estimates of their genetic diversity are shown in supporting informationTable S1. ...
Article
In the past decade, many researchers have published papers about hybridization between long-tailed and rhesus macaques. These previous works have proposed unidirectional gene flow with the Isthmus of Kra as the zoogeographical barrier of hybridization. However, these reports analyzed specimens of unknown origin and/or did not include specimens from Thailand, the center of the proposed area of hybridization. Collected specimens of long-tailed and rhesus macaques representing all suspected hybridization areas were examined. Blood samples from four populations each of long-tailed and rhesus macaques inhabiting Thailand, Myanmar, and Laos were collected and analyzed with conspecific references from China (for rhesus macaques) and multiple countries from Sundaic regions (for long-tailed macaques). Ninety-six single nucleotide polymorphism (SNP) markers specifically designed to interrogate admixture and ancestry were used in genotyping. We found genetic admixture maximized at the hybrid zone (15–20°N), as well as admixture signals of varying strength in both directions outside of the hybrid zone. These findings show that the Isthmus of Kra is not a barrier to gene flow from rhesus to long-tailed populations. However, to precisely identify a southernmost barrier, if in fact a boundary rather than simple isolation by distance exists, the samples from peninsular Malaysia must be included in the analysis. Additionally, a long-tailed to rhesus gene flow boundary was found between northern Thailand and Myanmar. Our results suggest that selection of long-tailed and rhesus macaques, the two most commonly used non-human primates for biomedical research, should take into account not only the species identification but also the origin of and genetic admixture within and between the species.
Article
Full-text available
The INHAND (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions Project (www.toxpath.org/inhand.asp) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP) and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative lesions in laboratory animals. The purpose of this publication is to provide a standardized nomenclature for classifying microscopic lesions observed in most tissues and organs from the nonhuman primate used in nonclinical safety studies. Some of the lesions are illustrated by color photomicrographs. The standardized nomenclature presented in this document is also available electronically on the internet (http://www.goreni.org/). Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions as well as lesions induced by exposure to test materials. Relevant infectious and parasitic lesions are included as well. A widely accepted and utilized international harmonization of nomenclature for lesions in laboratory animals will provide a common language among regulatory and scientific research organizations in different countries and increase and enrich international exchanges of information among toxicologists and pathologists.
Preprint
Full-text available
Human haemoglobin variants, such as sickle, confer protection against death from malaria; consequently, frequencies of such variants are often greatly elevated in humans from malaria endemic regions. Among non-human primates, the long-tailed macaque, Macaca fascicularis , also displays substantial haemoglobin variation. Almost all M. fascicularis haemoglobin variation is in the alpha globin chain, encoded by two linked genes: HBA1 and HBA2 . We demonstrate that alpha globin variation in M. fascicularis correlates with the strength of malaria selection. We identify a range of missense mutations in M. fascicularis alpha globin and demonstrate that some of these exhibit a striking HBA1 or HBA2 specificity, a pattern consistent with computational simulations of selection on genes exhibiting copy number variation. We propose that M. fascicularis accumulated amino acid substitutions in its alpha globin genes under malaria selection, in a process that closely mirrors, but does not entirely converge with, human malaria adaptation.
Article
In humans, abnormal thickening of the left ventricle of the heart clinically defines hypertrophic cardiomyopathy (HCM), a common inherited cardiovascular disorder that can precede a sudden cardiac death event. The wide range of clinical presentations in HCM obscures genetic variants that may influence an individual’s susceptibility to sudden cardiac death. Although exon sequencing of major sarcomere genes can be used to detect high-impact causal mutations, this strategy is successful in only half of patient cases. The incidence of left ventricular hypertrophy (LVH) in a managed research colony of rhesus macaques provides an excellent comparative model in which to explore the genomic etiology of severe HCM and sudden cardiac death. Because no rhesus HCM-associated mutations have been reported, we used a next-generation genotyping assay that targets 7 sarcomeric rhesus genes within 63 genomic sites that are orthologous to human genomic regions known to harbor HCM disease variants. Amplicon sequencing was performed on 52 macaques with confirmed LVH and 42 unrelated,unaffected animals representing both the Indian and Chinese rhesus macaque subspecies. Bias-reduced logistic regressionuncovered a risk haplotype in the rhesus MYBPC3 gene, which is frequently disrupted in both human and feline HCM; thishaplotype implicates an intronic variant strongly associated with disease in either homozygous or carrier form. Our results highlight that leveraging evolutionary genomic data provides a unique,practical strategy for minimizing population bias in complex disease studies.
Article
When nonhuman primate sperm undergoes cryopreservation in an egg yolk medium there is an increased risk that the egg yolk might adversely affect the sperm due to containing of avian pathogens. Although commercial egg-yolk-free medium for human sperm cryopreservation has been used for macaque sperm, the cryo-survival remains less than optimal. The present study, therefore, was conducted to determine the optimal concentration of antifreeze protein (AFP) III supplemented in a commercial egg-yolk-free medium for cynomolgus macaque (Macaca fascicularis) sperm cryo-survival. The function of frozen-thawed sperm was evaluated by post-thaw sperm motility, acrosome integrity, and mitochondrial function. Results indicate that the sperm motilities were greater when 0.1, 1, and 10 μg/ml of AFP III were supplemented into the sperm freezing medium (P < 0.05). In addition, the mitochondrial membrane potential was greater in the sperm cryopreserved with the medium that was supplemented with 0.1 μg/ml of AFP III (P < 0.05). The addition of AFP III at any of the concentrations, however, did not have any cryoprotection effect on the sperm acrosome, and the greatest concentrations of AFP III at 100 and 200 μg/ml had detrimental effects on acrosomal integrity (P < 0.05). Results of the present study indicated the methods used are effective for the cryopreservation of cynomolgus monkey sperm while reducing associated health risks due to avian pathogens being present in egg yolk-based extenders.
Article
Interest in the genetic composition of cynomolgus macaques (Macaca fascicularis) has increased due to the rising demandfor NHP models in human biomedical research. Significant genetic differences among regional populations of cynomolgus macaques can confound interpretations of research results because they do not solely reflect differences in experimental treatment effects. Therefore, the common origin of cynomolgus macaques used as research subjects should be verified by using region-specific genetic markers to minimize the influence of underlying genetic variation among animals selected as research subjects on phenotypes under study. We compared the effectiveness of 18 short tandem repeat (STR) markers with that of 83 single-nucleotide polymorphism (SNP) markers to differentiate the ancestry of cynomolgus macaques from 6 different populations (Cambodia, Sumatra, Mauritius, Singapore, and the islands of Luzon and Zamboanga in the Philippines).Genetic diversity indices such as allele numbers and expected heterozygosity based on SNP were lower and exhibited lower standard errors than those provided by STR, probably because, unlike STR, most SNP are biallelic and consequently exhibit maximal expected heterozygosity values of 0.50. However, the standard error of estimates of observed heterozygosity based on SNP was higher than that for STR, perhaps reflecting sampling errors. Only 27 SNP were required to match the resolving power of 17 STR to detect population structure, that is, 1.6 SNP:1 STR. Whereas STR only differentiated the Mauritian population from all other populations, SNP detected 4 genetically distinct groups (Cambodia, Singapore-Sumatra, Mauritius,and Zamboanga). SNP are poised to become as valuable as STR for understanding and detecting genetic structure amongcynomolgus macaques. Although STR will remain an important tool for cynomolgus macaque population studies, SNP have the potential to become the mainstream marker type.
Article
Full-text available
Background: Plasmodium knowlesi and Plasmodium cynomolgi are two malaria parasites naturally transmissible between humans and wild macaque through mosquito vectors, while Plasmodium inui can be experimentally transmitted from macaques to humans. One of their major natural hosts, the long-tailed macaque (Macaca fascicularis), is host to two other species of Plasmodium (Plasmodium fieldi and Plasmodium coatneyi) and is widely distributed in Southeast Asia. This study aims to determine the distribution of wild macaques infected with malarial parasites by examining samples derived from seven populations in five countries across Southeast Asia. Methods: Plasmodium knowlesi, P. cynomolgi, P. coatneyi, P. inui and P. fieldi, were detected using nested PCR assays in DNA samples from 276 wild-caught long-tailed macaques. These samples had been derived from macaques captured at seven locations, two each in the Philippines (n = 68) and Indonesia (n = 70), and one each in Cambodia (n = 54), Singapore (n = 40) and Laos (n = 44). The results were compared with previous studies of malaria parasites in long-tailed macaques from other locations in Southeast Asia. Fisher exact test and Chi square test were used to examine the geographic bias of the distribution of Plasmodium species in the macaque populations. Results: Out of 276 samples tested, 177 were Plasmodium-positive, with P. cynomolgi being the most common and widely distributed among all long-tailed macaque populations (53.3 %) and occurring in all populations examined, followed by P. coatneyi (20.4 %), P. inui (12.3 %), P. fieldi (3.4 %) and P. knowlesi (0.4 %). One P. knowlesi infection was detected in a macaque from Laos, representing the first documented case of P. knowlesi in wildlife in Laos. Chi square test showed three of the five parasites (P. knowlesi, P. coatneyi, P. cynomolgi) with significant bias in prevalence towards macaques from Malaysian Borneo, Cambodia, and Southern Sumatra, respectively. Conclusions: The prevalence of malaria parasites, including those that are transmissible to humans, varied among all sampled regional populations of long-tailed macaques in Southeast Asia. The new discovery of P. knowlesi infection in Laos, and the high prevalence of P. cynomolgi infections in wild macaques in general, indicate the strong need of public advocacy in related countries.
Article
Full-text available
Arlequin ver 3.0 is a software package integrating several basic and advanced methods for population genetics data analysis, like the computation of standard genetic diversity indices, the estimation of allele and haplotype frequencies, tests of departure from linkage equilibrium, departure from selective neutrality and demographic equilibrium, estimation or parameters from past population expansions, and thorough analyses of population subdivision under the AMOVA framework. Arlequin 3 introduces a completely new graphical interface written in C++, a more robust semantic analysis of input files, and two new methods: a Bayesian estimation of gametic phase from multi-locus genotypes, and an estimation of the parameters of an instantaneous spatial expansion from DNA sequence polymorphism. Arlequin can handle several data types like DNA sequences, microsatellite data, or standard multilocus genotypes. A Windows version of the software is freely available on http://cmpg.unibe.ch/software/arlequin3.
Article
Full-text available
Malaria is a vector-borne parasitic disease which is prevalent in many developing countries. Recently, it has been found that Plasmodium knowlesi, a simian malaria parasite can be life-threatening to humans. Long-tailed macaques, which are widely distributed in Malaysia, are the natural hosts for simian malaria, including P. knowlesi. The aim of the present study was to determine the prevalence of simian malaria parasites in long-tailed macaques in the district of Hulu Selangor, Selangor, Malaysia. A total of 70 blood samples were collected from Macaca fascicularis dwelling in the forest of Hulu Selangor by the Department of Wildlife and National Parks Peninsular Malaysia, Kuala Lumpur, Malaysia. DNA was extracted using PureLink™ Genomic DNA Kits. Conventional and nested PCR were used to detect the genus and species of Plasmodium parasites respectively. In addition, phylogenetic analysis was carried out to confirm the species of Plasmodium parasites. Thirty-five (50 %) of the 70 samples were positive for Plasmodium using genus-specific primers. These positive samples were then subjected to nested PCR targeting the 18S ribosomal RNA genes to detect all five simian malaria parasites: namely, P. knowlesi, Plasmodium inui, Plasmodium cynomolgi, Plasmodium fieldi, and Plasmodium coatneyi. All five species of simian malaria parasites were detected. Of these, P. inui was the predominant (65.7 %), followed by P. knowlesi (60 %), P. cynomolgi (51.4 %) P. coatneyi (45.7 %) and P. fieldi (2.9 %). A total of nine macaques had mono-infection with P. knowlesi (four), P. cynomolgi (two), P. coatneyi (two) and P. fieldi (one). Eleven of the macaques had dual infections while 12 had triple infections. Three macaques were infected with four species of Plasmodium. Molecular and phylogenetic analysis confirmed the five species of Plasmodium parasites. This study has provided evidence to elucidate the presence of transmission of malaria parasites among the local macaques in Hulu Selangor. Since malaria is a zoonosis, it is important to determine the new control strategies for the control of malaria.
Article
Full-text available
Since 1960, a total of seven species of monkey malaria have been reported as transmissible to man by mosquito bite: Plasmodium cynomolgi, Plasmodium brasilianum, Plasmodium eylesi, Plasmodium knowlesi, Plasmodium inui, Plasmodium schwetzi and Plasmodium simium. With the exception of P. knowlesi, none of the other species has been found to infect humans in nature. In this report, it is described the first known case of a naturally acquired P. cynomolgi malaria in humans. The patient was a 39-year-old woman from a malaria-free area with no previous history of malaria or travel to endemic areas. Initially, malaria was diagnosed and identified as Plasmodium malariae/P. knowlesi by microscopy in the Terengganu State Health Department. Thick and thin blood films stained with 10% Giemsa were performed for microscopy examination. Molecular species identification was performed at the Institute for Medical Research (IMR, Malaysia) and in the Malaria & Emerging Parasitic Diseases Laboratory (MAPELAB, Spain) using different nested PCR methods. Microscopic re-examination in the IMR showed characteristics of Plasmodium vivax and was confirmed by a nested PCR assay developed by Snounou et al. Instead, a different PCR assay plus sequencing performed at the MAPELAB confirmed that the patient was infected with P. cynomolgi and not with P. vivax. This is the first report of human P. cynomolgi infection acquired in a natural way, but there might be more undiagnosed or misdiagnosed cases, since P. cynomolgi is morphologically indistinguishable from P. vivax, and one of the most used PCR methods for malaria infection detection may identify a P. cynomolgi infection as P. vivax. Simian Plasmodium species may routinely infect humans in Southeast Asia. New diagnostic methods are necessary to distinguish between the human and monkey malaria species. Further epidemiological studies, incriminating also the mosquito vector(s), must be performed to know the relevance of cynomolgi malaria and its implication on human public health and in the control of human malaria. The zoonotic malaria cannot be ignored in view of increasing interactions between man and wild animals in the process of urbanization.
Article
Full-text available
Little is known about the role of gut microbiota in response to live oral vaccines against enteric pathogens. We examined the effect of immunization with an oral live-attenuated Shigella dysenteriae 1 vaccine and challenge with wild-type S. dysenteriae 1 on the fecal microbiota of cynomolgus macaques using 16 S rRNA analysis of fecal samples. Multi-dimensional cluster analysis identified different bacterial community types within macaques from geographically distinct locations. The fecal microbiota of Mauritian macaques, observed to be genetically distinct, harbored a high-diversity community and responded differently to Shigella immunization, as well as challenge compared to the microbiota in non-Mauritian macaques. While both macaque populations exhibited anti-Shigella antibody responses, clinical shigellosis was observed only among non-Mauritian macaques. These studies highlight the importance of further investigation into the possible protective role of the microbiota against enteric pathogens and consideration of host genetic backgrounds in conducting vaccine studies.
Article
Full-text available
SUMMARY Plasmodium knowlesi is a malaria parasite that is found in nature in long-tailed and pig-tailed macaques. Naturally acquired human infections were thought to be extremely rare until a large focus of human infections was reported in 2004 in Sarawak, Malaysian Borneo. Human infections have since been described throughout Southeast Asia, and P. knowlesi is now recognized as the fifth species of Plasmodium causing malaria in humans. The molecular, entomological, and epidemiological data indicate that human infections with P. knowlesi are not newly emergent and that knowlesi malaria is primarily a zoonosis. Human infections were undiagnosed until molecular detection methods that could distinguish P. knowlesi from the morphologically similar human malaria parasite P. malariae became available. P. knowlesi infections cause a spectrum of disease and are potentially fatal, but if detected early enough, infections in humans are readily treatable. In this review on knowlesi malaria, we describe the early studies on P. knowlesi and focus on the epidemiology, diagnosis, clinical aspects, and treatment of knowlesi malaria. We also discuss the gaps in our knowledge and the challenges that lie ahead in studying the epidemiology and pathogenesis of knowlesi malaria and in the prevention and control of this zoonotic infection.
Article
Full-text available
The evolution of primates is usually approached from the standpoint of adaptation and interspecific competition. However, climatic and eustatic changes associated with periodic glaciations have had a profound influence on their geographical distribution, favouring the intervention of contingency in evolution. This paper deals with the role of chance and competition in the dispersal and stocking of macaques in the islands of south-east Asia. The genus Macaca is unique among non-human primates for the range of habitats colonized, from continents to islands. We first review current knowledge about the zoogeography of macaques in Sundaland. We point out the inconsistencies present in the hypotheses thus far proposed to account for the colonization of shallow- and deep-water islands. We then propose a new perspective of macaque dispersal through the Indonesian archipelago, which takes into account sea-level changes, as well as latitudinal and altitudinal rainforest shifts following climatic cycles during the Quaternary. We envision three steps: (i) dispersal and partial disappearance of the first radiation of macaques; (ii) primary mainland recolonization by pigtailed and longtailed macaques; and (iii) secondary sea-rafting colonization by longtailed macaques. This model implies that liontailed, Sulawesi and Mentawai macaques stemmed from pre-glacial remnant populations, whereas pigtailed macaques originated in post-glacial populations that diverged later on. The model accounts for the distribution of longtailed macaques throughout the Indonesian archipelago. The riverine habits of this species would have favoured its dispersal by sea rafting, which was otherwise extremely rare for other primate species. Stocking would have been successful for longtailed macaques only in islands where no other macaque competitors were already present. © 2002 The Linnean Society of London, Biological Journal of the Linnean Society, 2002, 75, 555–576.
Article
Full-text available
In the foreseeable future there is little likelihood of achieving consensus on the number of Asian primate genera and species, and their subspecific composition. There is a more realistic hope of reaching agreement on the number of recognizable subspecies. The latter objective is more urgent because in order to reliably assess generic and specific numbers, it is essential that effective conservation measures are implemented for as many subspecies as possible. This cannot be comprehensively accomplished until their validity is assessed and they are satisfactorily established and defined. The Asian primate classification that we present is the outcome of electronic communication among the co-authors after a workshop, which was especially convened to attempt to determine the number of recognizable primate subspecies and to identify potentially recognizable subspecies. The generic and specific arrangement is a compromise that does not necessarily reflect the individual views of the co-authors: 183 subspecies in 77 species in 16 genera. The 31 subspecies allotted a low credibility rating are almost balanced by the 22 scientifically unnamed populations that may warrant subspecific status.
Article
Full-text available
Rhesus (Macaca mulatta) and long-tailed (M. fascicularis) macaques belong to the same species, and are parapatric within a zone that lies between 15° and 20° N on the Indochinese peninsula. Researchers have reported probable hybrids between the 2 species from that zone, but have not studied the extent of introgression. To test for phenotypic evidence of hybridization, we collected body mass, morphometrics (body size and proportions), and pelage color readings from free-ranging rhesus living close to the zonal boundary at Wat Tham Pa Mak Ho (WTPMH), Wang Saphun district, Loei province, northeastern Thailand (17°14′N, 101°47′E). Female WTPMH rhesus macaques (n =12) were 10–20% smaller, but with a greater relative tail length than the captive Chinese or Indian female rhesus. Female WTPMH were larger than the free-ranging long-tailed macaques, but with similar limb proportions and a shorter relative tail length. The WTPMH rhesus macaques also displayed the bipartite pelage color pattern typical of Macaca mulatta . The evidence suggests slight contribution of long-tailed macaques to the gene pool of the WTPMH population. Further sampling of other macaque populations within the zone and genetic analysis are essential to address better the question of hybridization. Determination of the distribution and range of biobehavioral variation of macaques within the zone is urgently needed, because their habitat is being rapidly destroyed by deforestation, and their demography and social structure are threatened by artificial disturbance.
Article
Full-text available
In light of the recent controversies over the role of animal models for research into the development of new treatments for severe malaria, particularly cerebral disease , a group of scientists came together to discuss the relative merits of a range of animal models and their overlap with the complex clinical syndromes of human disease. While it was not possible to fully resolve differences over the utility of the Plasmodium berghei ANKA model of experimental cerebral malaria, the meeting did bring the two research communities closer together to identify further work to provide information needed to validate the model and revitalise the development of other animal models displaying features of human pathology. The driving force behind this was the desire to ensure better translation of experimental findings into effective treatments for severe malaria.
Article
Full-text available
The nonhuman primates most commonly used in medical research are from the genus Macaca. To better understand the genetic differences between these animal models, we present high-quality draft genome sequences from two macaque species, the cynomolgus/crab-eating macaque and the Chinese rhesus macaque. Comparison with the previously sequenced Indian rhesus macaque reveals that all three macaques maintain abundant genetic heterogeneity, including millions of single-nucleotide substitutions and many insertions, deletions and gross chromosomal rearrangements. By assessing genetic regions with reduced variability, we identify genes in each macaque species that may have experienced positive selection. Genetic divergence patterns suggest that the cynomolgus macaque genome has been shaped by introgression after hybridization with the Chinese rhesus macaque. Macaque genes display a high degree of sequence similarity with human disease gene orthologs and drug targets. However, we identify several putatively dysfunctional genetic differences between the three macaque species, which may explain functional differences between them previously observed in clinical studies.
Article
Full-text available
Tafenoquine is an 8-aminoquinoline being developed for radical cure (blood and liver stage elimination) of Plasmodium vivax. During monotherapy treatment, the compound exhibits slow parasite and fever clearance times, and toxicity in glucose-6-phosphate dehydrogenase (G6PD) deficiency is a concern. Combination with other antimalarials may mitigate these concerns. In 2005, the radical curative efficacy of tafenoquine combinations was investigated in Plasmodium cynomolgi-infected naïve Indian-origin Rhesus monkeys. In the first cohort, groups of two monkeys were treated with a three-day regimen of tafenoquine at different doses alone and in combination with a three-day chloroquine regimen to determine the minimum curative dose (MCD). In the second cohort, the radical curative efficacy of a single-day regimen of tafenoquine-mefloquine was compared to that of two three-day regimens comprising tafenoquine at its MCD with chloroquine or artemether-lumefantrine in groups of six monkeys. In a final cohort, the efficacy of the MCD of tafenoquine against hypnozoites alone and in combination with chloroquine was investigated in groups of six monkeys after quinine pre-treatment to eliminate asexual parasites. Plasma tafenoquine, chloroquine and desethylchloroquine concentrations were determined by LC-MS in order to compare doses of the drugs to those used clinically in humans. The total MCD of tafenoquine required in combination regimens for radical cure was ten-fold lower (1.8 mg/kg versus 18 mg/kg) than for monotherapy. This regimen (1.8 mg/kg) was equally efficacious as monotherapy or in combination with chloroquine after quinine pre-treatment to eliminate asexual stages. The same dose of (1.8 mg/kg) was radically curative in combination with artemether-lumefantrine. Tafenoquine was also radically curative when combined with mefloquine. The MCD of tafenoquine monotherapy for radical cure (18 mg/kg) appears to be biologically equivalent to a 600-1200 mg dose in humans. At its MCD in combination with blood schizonticidal drugs (1.8 mg/kg), the maximum observed plasma concentrations were substantially lower than (20-84 versus 550-1,100 ng/ml) after administration of 1, 200 mg in clinical studies. Ten-fold lower clinical doses of tafenoquine than used in prior studies may be effective against P. vivax hypnozoites if the drug is deployed in combination with effective blood-schizonticidal drugs.
Article
Full-text available
Plasmodium knowlesi, a malaria parasite originally thought to be restricted to macaques in Southeast Asia, has recently been recognized as a significant cause of human malaria. Unlike the benign and morphologically similar P. malariae, these parasites can lead to fatal infections. Malaria parasites, including P. knowlesi, have not yet been detected in macaques of the Kapit Division of Malaysian Borneo, where the majority of human knowlesi malaria cases have been reported. In order to extend our understanding of the epidemiology and evolutionary history of P. knowlesi, we examined 108 wild macaques for malaria parasites and sequenced the circumsporozoite protein (csp) gene and mitochondrial (mt) DNA of P. knowlesi isolates derived from macaques and humans. We detected five species of Plasmodium (P. knowlesi, P. inui, P. cynomolgi, P. fieldi and P. coatneyi) in the long-tailed and pig-tailed macaques, and an extremely high prevalence of P. inui and P. knowlesi. Macaques had a higher number of P. knowlesi genotypes per infection than humans, and some diverse alleles of the P. knowlesi csp gene and certain mtDNA haplotypes were shared between both hosts. Analyses of DNA sequence data indicate that there are no mtDNA lineages associated exclusively with either host. Furthermore, our analyses of the mtDNA data reveal that P. knowlesi is derived from an ancestral parasite population that existed prior to human settlement in Southeast Asia, and underwent significant population expansion approximately 30,000-40,000 years ago. Our results indicate that human infections with P. knowlesi are not newly emergent in Southeast Asia and that knowlesi malaria is primarily a zoonosis with wild macaques as the reservoir hosts. However, ongoing ecological changes resulting from deforestation, with an associated increase in the human population, could enable this pathogenic species of Plasmodium to switch to humans as the preferred host.
Article
Full-text available
Comparative genomic analyses of primates offer considerable potential to define and understand the processes that mold, shape, and transform the human genome. However, primate taxonomy is both complex and controversial, with marginal unifying consensus of the evolutionary hierarchy of extant primate species. Here we provide new genomic sequence (~8 Mb) from 186 primates representing 61 (~90%) of the described genera, and we include outgroup species from Dermoptera, Scandentia, and Lagomorpha. The resultant phylogeny is exceptionally robust and illuminates events in primate evolution from ancient to recent, clarifying numerous taxonomic controversies and providing new data on human evolution. Ongoing speciation, reticulate evolution, ancient relic lineages, unequal rates of evolution, and disparate distributions of insertions/deletions among the reconstructed primate lineages are uncovered. Our resolution of the primate phylogeny provides an essential evolutionary framework with far-reaching applications including: human selection and adaptation, global emergence of zoonotic diseases, mammalian comparative genomics, primate taxonomy, and conservation of endangered species.
Article
Full-text available
Cynomolgus (or longtailed) macaques (Macaca fascicularis) are used extensively as laboratory animals in biomedical research. Their use in Singapore, an emerging biomedical hub in Southeast Asia, is now increasing widely, with research subjects currently originating from Singapore, Vietnam, and Pulau Bintan, Indonesia. Limited data exist on the genetic and phenotypic polymorphisms and phylogenetic relationships of these groups, and the animals are used as research subjects without regard to potential differences or homogeneity. Here we characterize their phenotypes by using established primatology tools to detail morphometrics and pelage erythrism and saturation. Pelage analyses supported the Gloger rule, in which heavily pigmented forms predominate near the equator, with Singaporean and Bintan macaques having darker pelage than Vietnamese macaques. Morphometric variation patterns suggest a tendency toward insular dwarfism and correlate generally with the Bergmann rule, in which body mass increases with latitude and colder climate. Although the 3 populations all belong to the nominotypical subspecies M. f. fascicularis, phenotypic differences are evident and are valuable tools to analyze their phylogeographic history and phylogenetic relationships.
Article
Full-text available
Genotypes for 13 short tandem repeats (STRs) were used to assess the genetic diversity within and differentiation among populations of rhesus macaques (Macaca mulatta) from mainland Asia and long-tailed macaques (M. fascicularis) from mainland and insular Southeast Asia. These animals were either recently captured in the wild or derived from wild-caught founders maintained in captivity for biomedical research.A large number of alleles is shared between the two macaque species but a significant genetic division between them persists. This distinction is more clear-cut among populations that are not, or are unlikely to have recently been, geographically contiguous. Our results suggest there has been significant interspecies nuclear gene flow between rhesus macaques and long-tailed macaques on the mainland. Comparisons of mainland and island populations of long-tailed macaques reflect marked genetic subdivisions due to barriers to migration. Geographic isolation has restricted gene flow, allowing island populations to become subdivided and genetically differentiated. Indonesian long-tailed macaques show evidence of long-term separation and genetic isolation from the mainland populations, while long-tailed macaques from the Philippines and Mauritius both display evidence of founder effects and subsequent isolation, with the impact from genetic drift being more profound in the latter.
Article
Full-text available
Rhesus macaque (Macaca mulatta) and long-tailed macaque (Macaca fascicularis) are the 2 most commonly used primate model species in biomedical sciences. Although morphological studies have revealed a weak hybridization at the interspecific contact zone, in the north of Indochina, a molecular study has suggested an ancient introgression from rhesus to long-tailed macaque into the Indo-Chinese peninsula. However, the gene flow between these 2 taxa has never been quantified using genetic data and theoretical models. In this study, we have examined genetic variation within and between the parapatric Chinese rhesus macaque and Indo-Chinese long-tailed macaque populations, using 13 autosomal, 5 sex-linked microsatellite loci and mitochondrial DNA sequence data. From these data, we assessed genetic structure and estimated gene flow using a Bayesian clustering approach and the "Isolation with Migration" model. Our results reveal a weak interspecific genetic differentiation at both autosomal and sex-linked loci, suggesting large population sizes and/or gene flow between populations. According to the Bayesian clustering, Chinese rhesus macaque is a highly homogeneous gene pool that contributes strongly to the current Indo-Chinese long-tailed macaque genetic makeup, whether or not current admixture is assumed. Coalescent simulations, which integrated the characteristics of the loci, pointed out 1) a higher effective population size in rhesus macaque, 2) no mitochondrial gene flow, and 3) unilateral and male-mediated nuclear gene flow of approximately 10 migrants per generation from rhesus to long-tailed macaque. These patterns of genetic structure and gene flow suggest extensive ancient introgression from Chinese rhesus macaque into the Indo-Chinese long-tailed macaque population.
Article
Full-text available
Macaca fascicularis is broadly distributed in Southeast Asia across 30 degrees of latitude and 35 degrees of longitude (Indochinese Peninsula, Isthmus of Kra, Malay Peninsula, Greater and Lesser Sunda Islands, Philippine Islands, and numerous small, neighboring islands). The range is divisible into 1) a core area comprised of mainland Southeast Asia, Borneo, Sumatra, and Java (large land masses interconnected during the last glacial maximum, 18,000 B.P.); 2) shallow-water fringing islands, which are smaller islands connected to the core area during the last glacial maximum; and 3) deep-water fringing islands, which are peripheral islands not connected to the core area during the last glacial maximum. Skull length was used to study effects of latitude and insularity on patterns of size variation. The data are from 802 adult M. fascicularis specimens from 140 core-area localities, 63 shallow-water islands, and 29 deep-water islands. Sex-specific polynomial regressions of skull length on latitude were used to describe skull length variation in the core area. These regressions served as standards for evaluating variation among samples from shallow-water and deep-water islands. The core area exhibits Bergmannian latitudinal size clines through most of the species range. Thus, skull length decreases from about 8 degrees S (Java) to the equator (Sumatra and Borneo), then increases as far north as about 13 degrees N (Isthmus of Kra). Farther north, to the northernmost Indochinese localities at about 17 degrees N, skull length in M. fascicularis decreases with increasing latitude, contrary to Bergmann's rule. Latitudinal size variation in shallow-water fringing islands generally parallels that in the core area. However, skull length tends to be smaller than in the core area at similar latitudes. Deep-water fringing islands are markedly more variable, with relatively small specimens in the Lesser Sunda Islands and relatively large specimens in the Nicobar Islands. These analyses illustrate how a primate species may vary in response to latitudinal temperature variation and to isolation.
Article
Macaca fascicularis fascicularis is distributed over a wide area of Southeast Asia. Thailand is located at the center of their distribution range and is the bridge connecting the two biogeographic regions of Indochina and Sunda. However, only a few genetic studies have explored the macaques in this region. To shed some light on the evolutionary history of M. f. fascicularis, including hybridization with M. mulatta, M. f. fascicularis and M. mulatta samples of known origins throughout Thailand and the vicinity were analyzed by molecular phylogenetics using mitochondrial DNA (mtDNA), including the hypervariable region 1, and Y-chromosomal DNA, including SRY and TSPY genes. The mtDNA phylogenetic analysis divided M. f. fascicularis into five subclades (Insular Indonesia, Sundaic Thai Gulf, Vietnam, Sundaic Andaman sea coast, and Indochina) and revealed genetic differentiation between the two sides of the Thai peninsula, which had previously been reported as a single group of Malay peninsular macaques. From the estimated divergence time of the Sundaic Andaman sea coast subclade, it is proposed that after M. f. fascicularis dispersed throughout Southeast Asia, some populations on the south-easternmost Indochina (eastern Thailand, southern Cambodia and southern Vietnam at the present time) migrated south-westwards across the land bridge, which was exposed during the glacial period of the late Pleistocene epoch, to the southernmost Thailand/northern peninsular Malaysia. Then, some of them migrated north and south to colonize the Thai Andaman sea coast and northern Sumatra, respectively. The SRY-TSPY phylogenetic analysis suggested that male-mediated gene flow from M. mulatta southward to M. f. fascicularis was restricted south of, but close to, the Isthmus of Kra. There was a strong impact of the geographical factors in Thailand, such as the Isthmus of Kra, Nakhon Si Thammarat, and Phuket ranges and Sundaland, on M. f. fascicularis biogeography and their hybridization with M. mulatta.
Article
Two subspecies of cynomolgus macaques (Macaca fascicularis) are alleged to co-exist in the Philippines, M. f. philippensis in the north and M. f. fascicularis in the south. However, genetic differences between the cynomolgus macaques in the two regions have never been studied to document the propriety of their subspecies status. We genotyped samples of cynomolgus macaques from Batangas in southwestern Luzon and Zamboanga in southwestern Mindanao for 15 short tandem repeat (STR) loci and sequenced an 835 bp fragment of the mtDNA of these animals. The STR genotypes were compared with those of cynomolgus macaques from southern Sumatra, Singapore, Mauritius and Cambodia, and the mtDNA sequences of both Philippine populations were compared with those of cynomolgus macaques from southern Sumatra, Indonesia and Sarawak, Malaysia. We conducted STRUCTURE and PCA analyses based on the STRs and constructed a median joining network based on the mtDNA sequences. The Philippine population from Batangas exhibited much less genetic diversity and greater genetic divergence from all other populations, including the Philippine population from Zamboanga. Sequences from both Batangas and Zamboanga were most closely related to two different mtDNA haplotypes from Sarawak from which they are apparently derived. Those from Zamboanga were more recently derived than those from Batangas, consistent with their later arrival in the Philippines. However, clustering analyses do not support a sufficient genetic distinction of cynomolgus macaques from Batangas from other regional populations assigned to subspecies M. f. fascicularis to warrant the subspecies distinction M. f. philippensis. Am J Phys Anthropol, 2014. © 2014 Wiley Periodicals, Inc.
Article
The crab-eating or long-tailed macaque (Macaca fascicularis) of tropical Southeast Asia is a widespread but rapidly declining species. The threats to the species are manifold and include habitat loss and degradation that increasingly result in conflict with expanding human populations in both rural and urban landscapes, as well as trapping and trade for pharmaceutical testing, research, and development. The greatest threat from the trade is in the Indochinese region, especially Cambodia where in 2003–2004 macaques began to be harvested from the wild, ostensibly for captive breeding for export to China and to the USA and elsewhere. The lucrative operations, however, may serve to “launder” wild-caught monkeys and appear to have resulted in their disappearance even from legally protected areas. Much of the impetus for this trade appears to be biowarfare research in the USA, the country that is the world's largest user of primates. Macaca fascicularis is classified as of “Least Concern” in the IUCN/SSC 2008 Red List of Threatened Species. It is imperative that the conservation status of the species be reassessed and that the impact of trade on the species be assessed by the CITES Secretariat.
Article
We estimate that between 25,000 and 35,000 long-tailed macaques, Macaca fascicularis, live on the island of Mauritius, 1,865 km2, in the western Indian Ocean, and we detail their distribution on the island. Probably introduced to Mauritius at some time in the 16th century, the macaques have been implicated by a succession of authors as agents both in the extinction of the bulk of the island’s unique vertebrate fauna, and in the destruction of its indigenous vegetation. Some of them have gone so far as to suggest that in view of their depredations the macaques should be eradicated from Mauritius. However, studies of the behavior and ecology of the macaques in both degraded savanna and native forest habitats, supplemented by surveys around the island, cast doubt upon this putative destructive role. Macaque population densities in Mauritius range from a maximum of around 1.3 individuals/ha in degraded savanna formations, to a minimum of approximately 0.33 individuals/ha in indigenous forest, and reflect a clear preference among these primates for secondary environments. Thus the long-tailed macaques in Mauritius, as in their southeast Asian homeland, best fit the profile of a ‘weed’ species that has simply exploited the disturbance by humans of the indigenous vegetation. They do not at the present time appear to pose a major threat to what remains of the remarkable indigenous vertebrate fauna of Mauritius, although they may help to disperse the seeds of invading exotic plant species in what remains of the indigenous forests.Copyright © 1986 S. Karger AG, Basel
Article
The genetic composition of cynomolgus macaques used in biomedical research is not as well-characterized as that of rhesus macaques. Populations of cynomolgus macaques from Sumatra, Corregidor, Mauritius, Singapore, Cambodia, and Zamboanga were analyzed using 24 STRs. The Sumatran and Cambodian populations exhibited the highest allelic diversity, while the Mauritian population exhibited the lowest. Sumatran cynomolgus macaques were the most genetically similar to all others, consistent with an Indonesian origin of the species. The high diversity among Cambodian animals may result from interbreeding with rhesus macaques. The Philippine and Mauritian samples were the most divergent from other populations, the former due to separation from the Sunda Shelf by deepwater and the latter due to anthropogenic translocation and extreme founder effects. Investigators should verify their research subjects' origin, ancestry, and pedigree to minimize risks to biomedical experimentation from genetic variance stemming from close kinship and mixed ancestry as these can obscure treatment effects.
Article
Objectives: Human Plasmodium knowlesi infections have been reported from several South-East Asian countries, excluding India, but its drug susceptibility profile in mixed-infection cases remains unknown. Methods: The chloroquine resistance transporter (CRT) and dihydrofolate reductase (DHFR) genes of P. knowlesi and other Plasmodium species were sequenced from clinical isolates obtained from malaria patients living in the Andaman and Nicobar Islands, India. The merozoite surface protein-1 and 18S rRNA genes of P. knowlesi were also sequenced from these isolates. Results: Among 445 samples analysed, only 53 of them had P. knowlesi-specific gene sequences. While 3 of the 53 cases (5.66%) had P. knowlesi monoinfection, the rest were coinfected with Plasmodium falciparum (86.79%, n = 46) or Plasmodium vivax (7.55%, n = 4), but none with Plasmodium malariae or Plasmodium ovale. There was discordance in the drug resistance-associated mutations among the coinfecting Plasmodium species. This is because the P. knowlesi isolates contained wild-type sequences, while P. falciparum isolates had mutations in the CRT and DHFR marker genes associated with a higher level of chloroquine and antifolate drug resistance, respectively. The mutation pattern indicates that the same patient, having a mixed infection, may be harbouring the drug-susceptible P. knowlesi parasite and a highly drug-resistant P. falciparum parasite. Conclusions: A larger human population in South-East Asia may be at risk of P. knowlesi infection than reported so far. The different drug susceptibility genotypes of P. knowlesi from its coinfecting Plasmodium species in mixed infections adds a new dimension to the malaria control programme, requiring formulation of an appropriate drug policy.
Article
Both phenotypic and genetic evidence for asymmetric hybridization between rhesus (Macaca mulatta) and cynomolgus (Macaca fascicularis) macaques has been observed in the region of Indochina where both species are sympatric. The large-scale sharing of major histocompatibility complex (MHC) class II alleles between the two species in this region supports the hypothesis that genes, and especially genes involved in immune response, are being transferred across the species boundary. This differential introgression has important implications for the incorporation of cynomolgus macaques of unknown geographic origin in biomedical research protocols. Our study found that for 2,808 single-nucleotide polymorphism (SNP) markers, the minor allele frequencies (MAF) and observed heterozygosity calculated from a sample of Vietnamese cynomolgus macaques was significantly different from those calculated from samples of both Chinese rhesus and Indonesian cynomolgus macaques. SNP alleles from Chinese rhesus macaques were overrepresented in a sample of Vietnamese cynomolgus macaques relative to their Indonesian conspecifics and located in genes functionally related to the primary immune system. These results suggest that Indochinese cynomolgus macaques represent a genetically and immunologically distinct entity from Indonesian cynomolgus macaques. Am. J. Primatol. 00:1-10, 2012. © 2012 Wiley Periodicals, Inc.
Article
The fascicularis group of macaques comprises four species: Macaca fascicularis, M. mulatta, M. cyclopis, and M. fuscata. The geographic ranges of M. fascicularis and M. mulatta are parapatric or marginally sympatric, with the former species widely distributed in insular and peninsular Southeast Asia and the latter species widely distributed in southern Asia; M. cyclopis is restricted to Taiwan, and M. fuscata is restricted to the Japanese archipelago. The four species in this group are compared with respect to pelage, external measurements and proportions, cranial characters, caudal vertebrae, molecular biology and genetics, natural history, and reproductive anatomy and behavior. In these species, head and body length and skull length generally increase with latitude, and tail length generally decreases with latitude; in shorter-tailed species, the number and length of caudal vertebrae is progressively reduced. Morphology of the glans penis in fascicularis-group species is uniquely derived among macaque species; morphology of the female tract in this group is similar to that in silenus-group species. Based on morphology and fossil history, a hypothesis is proposed concerning the evolution and dispersal of the fascicularis group.
Article
Crab-eating, or long-tailed, macaques [Macaca fascicularis (Raffles, 1821)] have been studied extensively throughout their distribution in South and South-east Asia. Despite this extensive body of research, the island population of long-tailed macaques from Singapore remains virtually undescribed. In the present study, we compare the morphometric variability and patterns of growth observed in a population sample from Singapore with a composite sample from Thailand, north of the Isthmus of Kra. The results of our analyses indicate that there are statistically significant differences between the two populations in adult size and shape. For both males and females, the Singapore population is smaller than the Thai population. Relative to body length, the Singapore macaques exhibit significantly longer tails, and, relative to cranial length, they exhibit significantly more narrow faces than the Thai macaques. Although levels of sexual dimorphism for most morphometric traits are very similar, indicating similar levels of male–male competition for females, the Singapore males exhibit a significantly larger testicular volume relative to body weight, suggestive of an alternative male reproductive strategy. In addition to adult somatometric size and shape, comparisons of growth patterns relative to age and body size reveal significant differences between the two population samples. Combined, these results suggest either that statistically significant differences in adult morphology and patterns of growth can occur in presumably reproductively cohesive subspecies, or the Singapore macaques may be taxonomically distinct. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 92, 675–694.
Article
Seven species of malaria naturally infect eight species of macaques in southwestern India, Sri Lanka, and Southeast Asia. Within malarious areas, the frequency of infections in infected species of macaques varies from 9 to 61%. Natural malarial infections in macaques are relatively benign. The proved or probable vectors of macaque malaria are seven species of mosquitoes that belong to the Leucosphyrus Group of the genus Anopheles. The geographic distribution of macaque malaria apparently is determined by the distribution of the Leucosphyrus Group of mosquitoes, which in turn apparently is determined by the distribution of tropical evergreen rain forest. Experimental infections with three species of macaque malaria frequently are lethal to populations or species of macaques that inhabit areas outside the geographic ranges of the parasites. In populations or species of macaques that are sympatric with experimentally virulent species of malaria, partial resistance probably evolved as a consequence of natural selection acting on favorable mutations.
Article
Based on collectors' measurements of 1,040 specimens, variation of relative tail length [RTL = (tail length/head and body length) × 100] has been studied inMacaca fascicularis andM. mulatta, two closely related species that replace one another in tropical Asia and subtropical Asia, respectively. RTL usually is greater than 90 inM. fascicularis and usually is less than 60 inM. mulatta; intermediate values occur in only 3.5% of specimens studied. Within each species, RTL is approximately equal in females and males. From infancy to adulthood, RTL tends to decline in both species. InM. fascicularis, RTL generally decreases with increasing latitude; inM. mulatta, RTL is approximately constant latitudinally. Where the geographic ranges of these two species meet at ca. 15°N in the Indochinese Peninsula, a few specimens have been collected in which RTL and dorsal pelage color are intermediate between those inM. fascicularis andM. mulatta. The observed pattern of variation suggests that the ranges ofM. fascicularis andM. mulatta formerly were separated by a zoogeographic barrier — perhaps during a Pleistocene glacial interval. After disappearance of the postulated barrier, the ranges of these two species apparently became contiguous and limited hybridization has occurred.
Chapter
The abstract for this document is available on CSA Illumina.To view the Abstract, click the Abstract button above the document title.
Article
Although the rhesus macaque (Macaca mulatta) is commonly used for biomedical research and becoming a preferred model for translational medicine, quantification of genome-wide variation has been slow to follow the publication of the genome in 2007. Here we report the properties of 4040 single nucleotide polymorphisms discovered and validated in Chinese and Indian rhesus macaques from captive breeding colonies in the United States. Frequency-matched measures of linkage disequilibrium were much greater in the Indian sample. Although the majority of polymorphisms were shared between the two populations, rare alleles were over twice as common in the Chinese sample. Indian rhesus had higher rates of heterozygosity, as well as previously undetected substructure, potentially due to admixture from Burma in wild populations and demographic events post-captivity.
Article
Major histocompatibility complex (MHC) molecules play an important role in the susceptibility and/or resistance to many diseases. To gain an insight into the MHC background and to facilitate the experimental use of cynomolgus macaques, the second exon of the MhcMafa-DOB, -DPB1, and -DQB1 genes from 143 cynomolgus macaques were characterized by cloning to sequencing. A total of 16 Mafa-DOB, 16 Mafa-DPB1, and 34 Mafa-DQB1 alleles were identified, which revealed limited, moderate, and marked allelic polymorphism at DOB, DPB1, and DQB1, respectively, in a cohort of cynomolgus macaques of Vietnamese origin. In addition, 16 Mafa-DOB, 5 Mafa-DPB1, and 8 Mafa-DQB1 alleles represented novel sequences that had not been reported in earlier studies. Almost of the sequences detected at the DOB and DQB1 locus in the present study belonged to DOB*01 (100%) and DQB1*06 (62%) lineages, respectively. Interestingly, four, three, and one high-frequency alleles were detected at Mafa-DOB, -DPB1, and -DQB1, respectively, in this monkeys. The alleles with the highest frequency among these monkeys were Mafa-DOB*010102, Mafa-DPB1*13, and Mafa-DQB1*0616, and these were found in 33 (25.6%) of 129 monkeys, 32 (31.37%) of 102 monkeys, and 30 (31%) of 143 monkeys, respectively. The high-frequency alleles may represent high priority targets for additional characterization of immune function. We also carried out evolutionary and population analyses using these sequences to reveal population-specific alleles. This information will not only promote the understanding of MHC diversity and polymorphism in the cynomolgus macaque but will also increase the value of this species as a model for biomedical research.
Article
Plasmodium knowlesi is a malaria parasite of Old World monkeys and is infectious to humans. In this study Macaca fascicularis was used as a model to understand the host response to P. knowlesi using parasitological and haematological parameters. Three M. fascicularis of either sex were experimentally infected with P. knowlesi erythrocytic parasites from humans. The pre-patent period for P. knowlesi infection in M. fascicularis ranged from seven to 14 days. The parasitemia observed was 13,686-24,202 parasites per microL of blood for asexual stage and 88-264 parasites per microL of blood for sexual stage. Periodicity analysis adopted from microfilaria periodicity technique of asexual stage showed that the parasitemia peak at 17:39h while the sexual stage peaked at 02:36 h. Mathematical analysis of the data indicates that P. knowlesi gametocytes tend to display periodicity with a peak (24:00-06:00) that coincides with the peak biting activity (19:00-06:00) of the local vector, Anopheles latens. The morphology of P. knowlesi resembled P. falciparum in early trophozoite and P. malariae in late trophozoite. However, it may be distinguishable by observing the appliqué appearance of the cytoplasm and the chromatin lying inside the ring. Haematological analysis on macaques with knowlesi malaria showed clinical manifestations of hypoglycaemia, anaemia and hyperbilirubinemia. Gross examination of spleen and liver showed malaria pigments deposition in both organs.
Article
The geographic ranges of rhesus (Macaca mulatta) and cynomolgus (M. fascicularis) macaques adjoin in Indochina where they appear to hybridize. We used published and newly generated DNA sequences from 19 loci spanning approximately 20 kb to test whether introgression has occurred between these macaque species. We studied introgression at the level of nuclear DNA and distinguished between incomplete lineage sorting of ancestral polymorphisms or interspecific gene flow. We implemented a divergence population genetics approach by fitting our data to an isolation model implemented in the software IMa. The model that posits no gene flow from the rhesus into the cynomolgus macaque was rejected (P = 1.99 x 10(-8)). Gene flow in this direction was estimated as 2Nm approximately 1.2, while gene flow in the reverse direction was nonsignificantly different from zero (P = 0.16). The divergence time between species was estimated as approximately 1.3 million years. Balancing selection, a special case of incomplete sorting, was taken into consideration, as well as potential crossbreeding in captivity. Parameter estimates varied between analyses of subsets of data, although we still rejected isolation models. Geographic sampling of the data, where samples of cynomolgus macaques derived from Indochina were excluded, revealed a lost signature of gene flow, indicating that interspecific gene flow is restricted to mainland Indochina. Our results, in conjunction with those by others, justify future detailed analyses into the genetics of reproductive barriers and reticulate evolution in these two genome-enabled primates. Future studies of the natural hybridization between rhesus and cynomolgus macaques would expand the repertoire of systems available for speciation studies in primates.
Article
Highly purified Plasmodium knowlesi schizonts were used to produce a hyperimmune anti-parasite serum in a rhesus monkey. Proteins of membranes from normal and P. knowlesi-infected erythrocytes, as well as purified schizonts, were solubilized in 1% Triton X-100 and analyzed by bidimensional electrophoretic techniques. Of seven parasite-specific antigens identified in membranes of parasitized erythrocytes by crossed immune electrophoresis against monkey anti-parasite serum, only three could be detected in the purified schizonts. Bidimensional focusing-dodecyl sulfate/polyacrylamide gel electrophoresis of membranes from parasitized cells revealed three proteins, in the 55,000-90,000 molecular weight region, with isoelectric points between pH 4.5 and pH 5.2, that could not be detected in normal membranes or purified schizonts. Membranes of normal erythrocytes and uninfected erythrocytes that had been incubated with sera from monkeys with 25-50% parasitemia did not react with the monkey anti-parasite serum.
Article
This report summarizes the results of a comparative study of the major features of untreated infections with the B strain of Plasmodium cynomolgi in Macaca mulatta, M. irus (fascicularis), M. nemestrina, M. speciosa (arctoides), and Cercopithecus aethiops. The investigation included: delineation of the courses of trophozoite induced and sporozoite induced infections in these Old World primates; evaluation of their efficiencies in transmitting the above plasmodium through Anopheles freeborni; and assessment of host reactions to infection, with particular attention to impacts on erythroid elements of peripheral blood. In all important respects, the parasitic courses of infections in M. mulatta and C. aethiops (Kenyan origin) were identical, as were the reactions of these hosts to disease processes. M. mulatta was slightly more efficient than C. aethiops in transmitting P. cynomolgi through A. freeborni; however, this favored position may have been purchased by experimental design. The features of infections in M. irus, M. nemestrina, and M. speciosa differed significantly from those in M. mulatta. M. irus responded to challenge with trophozoites or sporozoites in a highly reproducible manner, but exhibited peak parasitemias and a long series of parasitic waves (recrudescences and/or relapses) of much lower intensities than were encountered in M. mulatta. M. nemestrina responded to such challenges in diverse manners. A few subjects exhibited parasitic courses almost identical with those encountered in M. irus. The majority exhibited extremely low level parasitemias of great persistence. These diverse parasitic courses were associated with specific physical features of this monkey. M. speciosa failed to support infections following inoculation with either trophozoites or sporozoites. Sporozoite challenges did lead to transient, extremely low level parasitemias, indicating that tissue stage schizogony had taken place. The unusual features of infections in M. nemestrina and M. speciosa could be of substantial interest to those concerned with factors which determine invasion of erythrocytes by plasmodia. Demonstration that untreated infections in M. mulatta and C. aethiops are essentially identical is of far more immediate importance. If responses of infections in these hosts to standard antimalarial drugs are also identical, the way is open to substituting C. aethiops for M. mulatta in studies on the biology and therapy of infections with P. cynomolgi, particularly in the search for radical curative drugs. Such substitution would meet a critical need at a time when access to feral M. mulatta is restricted.
Article
This report summarizes the results of a comparative study of the virulence of the "S-M," H, and C strains of P. knowlesi for Indian rhesus monkeys (Macaca mulatta) and cynomolgus monkeys [M. irus (fascicularis)] of Malayan (West Malaysia) and Philippine origins. Each of the above strains produced fulminating, uniformly fatal infections in the rhesus monkey and mild, chronic infections, characterized by relatively low level parasitemias in cynomolgus monkeys of Philippine origin. In striking contrast, the H and C strains produced infections in cynomolgus monkeys of Malayan origin which were indistinguishable in severity from infections produced in M. mulatta. The circumstances of the study precluded evaluation of the virulence of the "S-M" strain for M. irus of Malayan origin. Even so, the available data make it necessary to qualify the long-held belief that infections with P. knowlesi in M. irus invariably follow a benign course.
Article
Macaca fascicularis monkeys from Mauritius were shown to be susceptible via sporozoite inoculation to 7 species of Plasmodium (P. fragile, P. coatneyi, P. gonderi, P. inui, P. cynomolgi, P. knowlesi, and P. fieldi), indigenous to macaques in southeastern Asia. Four monkeys were sequentially infected with different species of Plasmodium to determine maximum and course of parasitemia. In 2 nonsplenectomized monkeys, P. fragile developed maximum parasite counts of only 134 and 155/microliters. For Plasmodium knowlesi, a parasite that is life-threatening to rhesus monkeys, maximum parasite counts were 4,278 and 7,440/microliters. Plasmodium coatneyi developed to what must be considered as moderate levels. After animals underwent splenectomy, parasite counts of P. coatneyi were 58,280, 89,094, 4,464, and 43,524/microliters. The maximum parasite counts for P. gonderi (13,508 and 21,576/microliters) and P. fieldi (1,767 and 17,836/microliters) were lower than would be expected in M. mulatta. In 2 monkeys that developed patent parasitemia with P. inui, the maximum parasite counts (95,046 and 728,748/microliters) indicated that this parasite may be the best adapted species for development in these animals once infection is established. Finally, the reinfection of 2 monkeys with P. cynomolgi suggested that some animals may be basically more resistant than others, whether splenectomized or not, to the production of high-density parasitemia.
Article
In this review are discussed: the life cycle of the malarial parasite; malarial parasites of monkeys; malarial parasites of anthropoid apes; human malarias in subhuman primates; and malarias of subhuman primates in man.
Capability of captive born cynomolgus monkeys to substitute for rhesus in the Plasmodium cynomolgi radical curative antimalarial drug development model was examined. Eighteen monkeys divided into 3 groups were given standard or high doses of sporozoites intravenously. One group of 4 received 0.8 - 1.6 X 10(6) and a second group of 8 received 0.3 - 1.0 X 10(7) sporozoites. The third group of 6 was splenectomized and then received 3.0 - 4.0 X 10(6). The 2 groups of intact monkeys developed a persistent low level parasitemia; however, gametocyte production was poor. The splenectomized group developed a persistent parasitemia with a higher mean, which more closely resembled rhesus parasitemias. A high, post-patent leukocytosis consisting primarily of lymphocytes was observed in this group. Good gametocyte production resulted in the splenectomized group and oocysts were produced from all lots of Anopheles dirus which fed on them. Following clearance of blood forms, relapse potential was demonstrated in the 2 splenectomized monkeys tested. In this study the splenectomized captive born cynomolgus appeared to be capable of supplementing rhesus as an antimalarial drug testing model.
Article
Attempts to transmit the classical M strain of Plasmodium cynomolgi to man via mosquito resulted in a low-grade infection in only one (a Caucasian) of eleven volunteers, two Negroes and nine whites. Subsequent passage of this strain through human volunteers increased its capacity to produce infections and clinical manifestations. Residence in the human subject did not alter the capacity of the strain to produce characteristic M-type infections in the rhesus monkey.
Article
On May 8, 1960, one of the staff of the Parasitology Section of this Institute developed a febrile illness subsequently diagnosed as malaria. Paroxysms of tertian periodicity were produced by a parasite morphologically indistinguishable from Plasmodium vivax. Transfer of the infections from this laboratory worker to a normal rhesus monkey suggested the possibility of accidental transmission to man of one of the strains of Plasmodium cynomolgi under study in the Institute. Systematic efforts to confirm the above suggestion followed. Human volunteers were bitten by mosquitoes heavily infected with either the bastianellii or M strain of P. cynomolgi. Two of two volunteers inoculated with the bastianellii strain developed patent infections which could be transferred back to the rhesus monkey via injection of human blood. None of the 7 volunteers inoculated with the M strain developed a parasitemia detectable on examination of thick blood films. Blood from one of these volunteers, taken at a time of low-grade fever, did produce an atypical malarial infection in a rhesus monkey. However, typical infections resulted from either blood or sporozoite transfer of the parasites from this monkey to other normal animals. These developments appear to warrant the conclusions: (1) that the original infection was doubtless caused by accidental transmission of the bastianellii strain of P. cynomolgi; (2) that infection with either the bastianellii or M strain of P. cynomolgi can be transmitted to man; and (3) that transmission of the more recently isolated bastianellii strain can be accomplished more readily than can transmission of the M strain which has been carried in the laboratory by blood to blood transfer for more than 25 years. Stress has been laid on the need for open-minded evaluation of the significance of these findings to malaria eradication and control problems in various parts of the world.
Article
Temperatures which inhibit crown-gall tumorigenesis in Kalanchoé daigremontiana plants also accelerate the rate of wound healing and the rate at which cells in the wound area become competent to react to the tumorigenic stimulus. The concept that the "tumor-inducing principle" is thermolabile and of high molecular weight may be invalid since it is based in part on the lack of effect of temperature on wound healing and conditioning. The rate of division of host cells may determine the success of crown-gall tumorigenesis.
Article
About a fifth of malaria cases in 1999 for the Kapit division of Malaysian Borneo had routinely been identified by microscopy as Plasmodium malariae, although these infections appeared atypical and a nested PCR assay failed to identify P malariae DNA. We aimed to investigate whether such infections could be attributable to a variant form of P malariae or a newly emergent Plasmodium species. We took blood samples from 208 people with malaria in the Kapit division between March, 2000, and November, 2002. The small subunit ribosomal RNA and the circumsporozoite protein genes were sequenced for eight isolates that had been microscopically identified as P malariae. All blood samples were characterised with a genus-specific and species-specific nested PCR assay together with newly designed P knowlesi-specific primers. All DNA sequences were phylogenetically indistinguishable from those of P knowlesi, a malaria parasite of long-tailed macaque monkeys, but were significantly different from other malaria parasite species. By PCR assay, 120 (58%) of 208 people with malaria tested positive for P knowlesi, whereas none was positive for P malariae. P knowlesi parasites in human erythrocytes were difficult to distinguish from P malariae by microscopy. Most of the P knowlesi infections were in adults and we did not note any clustering of cases within communities. P knowlesi infections were successfully treated with chloroquine and primaquine. Naturally acquired P knowlesi infections, misdiagnosed by microscopy mainly as P malariae, accounted for over half of all malaria cases in our study. Morphological similarities between P knowlesi and P malariae necessitate the use of molecular methods for correct identification. Further work is needed to determine whether human P knowlesi infections in the Kapit division are acquired from macaque monkeys or whether a host switch to human beings has occurred.
Article
DNA was extracted from the buffy coats or serum of 212 rhesus macaques (Macaca mulatta) sampled throughout the species' geographic range. An 835 base pair (bp) fragment of mitochondrial DNA (mtDNA) was amplified from each sample, sequenced, aligned, and used to estimate genetic distances from which phylogenetic trees were constructed. A tree that included sequences from rhesus macaques whose exact origins in China are known was used to determine the regional origin of clusters of haplotypes, or haplogroups, defined by the trees. Indian rhesus sequences formed one large homogeneous haplogroup with very low levels of nucleotide diversity and no geographic structure, and a second much smaller haplogroup apparently derived from Burma. The sequences from Burma and eastern and western China were quite divergent from those in the major haplogroup of India. Each of these sequences formed separate clusters of haplotypes that exhibited far greater nucleotide diversity and/or population structure. Correspondingly, sequences from Indian rhesus macaques that are considered to represent different subspecies (based on morphological differences) were intermingled in the tree, while those from China reflected some, but not all, aspects of subspecific taxonomy. Regional variation contributed 72% toward the paired differences between sequences in an analysis of molecular variance (AMOVA), and the average differences between the populations of eastern and western China were also statistically significant. These results suggest that Indian and Chinese rhesus macaques were reproductively isolated during most, if not all, of the Pleistocene, during which time Indian rhesus macaques experienced a severe genetic bottleneck, and that some gene flow westward into India was subsequently reestablished. Samples from breeding centers in three different provinces of China included sequences from rhesus macaques that originated in both eastern (or southern) and western China, confirming anecdotal reports that regional breeding centers in China exchange breeding stock. Genetic differences among rhesus macaques (even those acquired from the same regional breeding center) that originate in different geographic regions and are employed as subjects in biomedical experiments can contribute to phenotypic differences in the traits under study.