[Show abstract][Hide abstract] ABSTRACT: We describe a genome reference of the African green monkey or vervet (Chlorocebus aethiops). This
member of the Old World monkey (OWM) superfamily is uniquely valuable for genetic investigations of
simian immunodeficiency virus (SIV), of which it is the most abundant natural host species, and of a wide
range of health-related phenotypes assessed in Caribbean vervets (C. a. sabaeus), whose numbers have
Downloaded from genome.cshlp.org on September 16, 2015 - Published by Cold Spring Harbor Laboratory Press
expanded dramatically since Europeans introduced small numbers of their ancestors from West Africa
during the colonial era. We use the reference to characterize the genomic relationship between vervets
and other primates, the intrageneric phylogeny of vervet subspecies, and genome-wide structural
variations of a pedigreed C. a. sabaeus population. Through comparative analyses with human and rhesus
macaque, we characterize at high resolution the unique chromosomal fission events that differentiate the
vervets and their close relatives from most other catarrhine primates, in whom karyotype is highly
conserved. We also provide a summary of transposable elements and contrast these with the rhesus
macaque and human. Analysis of sequenced genomes representing each of the main vervet subspecies
supports previously hypothesized relationships between these populations, which range across most of
sub-Saharan Africa, while uncovering high levels of genetic diversity within each. Sequence-based
analyses of major histocompatibility complex (MHC) polymorphisms reveal extremely low diversity in
Caribbean C. a. sabaeus vervets, as compared to vervets from putatively ancestral West African regions.
In the C. a. sabaeus research population we discover the first structural variations that are in some cases
predicted to have a deleterious effect; future studies will determine the phenotypic impact of these
[Show abstract][Hide abstract] ABSTRACT: We describe a genome reference of the African green monkey or vervet (Chlorocebus aethiops). This member of the Old World monkey (OWM) superfamily is uniquely valuable for genetic investigations of simian immunodeficiency virus (SIV), of which it is the most abundant natural host species, and of a wide range of health-related phenotypes assessed in Caribbean vervets (C. a. sabaeus), whose numbers have expanded dramatically since Europeans introduced small numbers of their ancestors from West Africa during the colonial era. We use the reference to characterize the genomic relationship between vervets and other primates, the intrageneric phylogeny of vervet subspecies, and genome-wide structural variations of a pedigreed C. a. sabaeus population. Through comparative analyses with human and rhesus macaque, we characterize at high resolution the unique chromosomal fission events that differentiate the vervets and their close relatives from most other catarrhine primates, in whom karyotype is highly conserved. We also provide a summary of transposable elements and contrast these with the rhesus macaque and human. Analysis of sequenced genomes representing each of the main vervet subspecies supports previously hypothesized relationships between these populations, which range across most of sub-Saharan Africa, while uncovering high levels of genetic diversity within each. Sequence-based analyses of major histocompatibility complex (MHC) polymorphisms reveal extremely low diversity in Caribbean C. a. sabaeus vervets, as compared to vervets from putatively ancestral West African regions. In the C. a. sabaeus research population we discover the first structural variations that are in some cases predicted to have a deleterious effect; future studies will determine
Genome Research 09/2015; DOI:10.1101/gr.192922.115 · 14.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Gibbons are small arboreal apes that display an accelerated rate of evolutionary chromosomal rearrangement and occupy a key node in the primate phylogeny between Old World monkeys and great apes. Here we present the assembly and analysis of a northern white-cheeked gibbon (Nomascus leucogenys) genome. We describe the propensity for a gibbon-specific retrotransposon (LAVA) to insert into chromosome segregation genes and alter transcription by providing a premature termination site, suggesting a possible molecular mechanism for the genome plasticity of the gibbon lineage. We further show that the gibbon genera (Nomascus, Hylobates, Hoolock and Symphalangus) experienced a near-instantaneous radiation 5 million years ago, coincident with major geographical changes in southeast Asia that caused cycles of habitat compression and expansion. Finally, we identify signatures of positive selection in genes important for forelimb develop-ment (TBX5) and connective tissues (COL1A1) that may have been involved in the adaptation of gibbons to their arboreal habitat. Gibbons (Hylobatidae) are critically endangered 1 small apes that inhabit the tropical forests of southeast Asia (Fig. 1) and belong to the super-family Hominoidea along with great apes and humans. In the primate phylogeny, gibbons diverged between Old World monkeys and great apes, providing a unique perspective from which to study the origins of hominoid characteristics. Gibbons have several distinctive traits, the most striking of which is the unusually high number of large-scale chromosomal rearrangements in comparison to the inferred ancestral ape karyotype 2
[Show abstract][Hide abstract] ABSTRACT: We report the whole-genome sequence of the common marmoset (Callithrix jacchus). The 2.26-Gb genome of a female marmoset was assembled using Sanger read data (6x) and a whole-genome shotgun strategy. A first analysis has permitted comparison with the genomes of apes and Old World monkeys and the identification of specific features that might contribute to the unique biology of this diminutive primate, including genetic changes that may influence body size, frequent twinning and chimerism. We observed positive selection in growth hormone/insulin-like growth factor genes (growth pathways), respiratory complex I genes (metabolic pathways), and genes encoding immunobiological factors and proteases (reproductive and immunity pathways). In addition, both protein-coding and microRNA genes related to reproduction exhibited evidence of rapid sequence evolution. This genome sequence for a New World monkey enables increased power for comparative analyses among available primate genomes and facilitates biomedical research application.
[Show abstract][Hide abstract] ABSTRACT: In the purpose of studying the distribution of total and non-histone proteins along the chromosome and the relationships between protein distribution and trypsin bands, cells from Chinese hamster cultures (C-125) were labelled with 3H-lysine and 3H-tryptophan, respectively. The results show that 3H-lysine labelled chromosomes are more heavily labelled than chromosomes from cells labelled with 3H-tryptophan, and that the amount of labelling decreases in both cases after trypsin treatment. It has also been found that both types of proteins are uniformely distributed along the chromosome in the absence of trypsin treatment, while after this treatment clustering of silver grains over dark G-bands on 3H-lysine labelled chromosomes can be observed. 3H-tryptophan labelling is markedly decreased after trypsin treatment.
[Show abstract][Hide abstract] ABSTRACT: Chromosome rearrangements in small apes are up to 20 times more frequent than in most mammals. Because of their complexity, the full extent of chromosome evolution in these hominoids is not yet fully documented. However, previous work with array painting, BAC-FISH and selective sequencing in two of the four karyomorphs, has shown that high resolution methods can precisely define chromosome breakpoints and map the complex flow of evolutionary chromosome rearrangements. Here we use these tools to precisely define the rearrangements that have occurred in the remaining two karyomorphs, genera Symphalangus (2n=50), and Hoolock (2n=38). This research provides the most comprehensive insight into the evolutionary origins of chromosome rearrangements involved in transforming small apes genome. Bioinformatics analyses of the human-gibbon synteny breakpoints revealed association with transposable elements and segmental duplications providing some insight into the mechanisms that might have promoted rearrangements in small apes. In the near future, the comparison of gibbon genome sequences will provide novel insights to test hypotheses concerning the mechanisms of chromosome evolution. The precise definition of synteny block boundaries and orientation, chromosomal fusions, and centromere repositioning event presented here will facilitate genome sequence assembly for these close relatives of humans.
Genome Research 08/2012; 22(12). DOI:10.1101/gr.138651.112 · 14.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The catarrhine primates were the first group of species studied with comparative molecular cytogenetics. Many of the fundamental techniques and principles of analysis were initially applied to comparisons in these primates, including interspecific chromosome painting, reciprocal chromosome painting and the extensive use of cloned DNA probes for evolutionary analysis. The definition and importance of chromosome syntenies and associations for a correct cladistics analysis of phylogenomic relationships were first applied to catarrhines. These early chromosome painting studies vividly illustrated a striking conservation of the genome between humans and macaques. Contemporarily, it also revealed profound differences between humans and gibbons, a group of species more closely related to humans, making it clear that chromosome evolution did not follow a molecular clock. Chromosome painting has now been applied to more that 60 primate species and the translocation history has been mapped onto the major taxonomic divisions in the tree of primate evolution. In situ hybridization of cloned DNA probes, primarily BAC-FISH, also made it possible to more precisely map breakpoints with spanning and flanking BACs. These studies established marker order and disclosed intrachromosomal rearrangements. When applied comparatively to a range of primate species, they led to the discovery of evolutionary new centromeres as an important new category of chromosome evolution. BAC-FISH studies are intimately connected to genome sequencing, and probes can usually be assigned to a precise location in the genome assembly. This connection ties molecular cytogenetics securely to genome sequencing, assuring that molecular cytogenetics will continue to have a productive future in the multidisciplinary science of phylogenomics.
Cytogenetic and Genome Research 06/2012; 137(2-4):273-84. DOI:10.1159/000339381 · 1.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Gibbons (Hylobatidae) shared a common ancestor with the other hominoids only 15-18 million years ago. Nevertheless, gibbons show very distinctive features that include heavily rearranged chromosomes. Previous observations indicate that this phenomenon may be linked to the attenuated epigenetic repression of transposable elements (TEs) in gibbon species. Here we describe the massive expansion of a repeat in almost all the centromeres of the eastern hoolock gibbon (Hoolock leuconedys). We discovered that this repeat is a new composite TE originating from the combination of portions of three other elements (L1ME5, AluSz6, and SVA_A) and thus named it LAVA. We determined that this repeat is found in all the gibbons but does not occur in other hominoids. Detailed investigation of 46 different LAVA elements revealed that the majority of them have target site duplications (TSDs) and a poly-A tail, suggesting that they have been retrotransposing in the gibbon genome. Although we did not find a direct correlation between the emergence of LAVA elements and human-gibbon synteny breakpoints, this new composite transposable element is another mark of the great plasticity of the gibbon genome. Moreover, the centromeric expansion of LAVA insertions in the hoolock closely resembles the massive centromeric expansion of the KERV-1 retroelement reported for wallaby (marsupial) interspecific hybrids. The similarity between the two phenomena is consistent with the hypothesis that evolution of the gibbons is characterized by defects in epigenetic repression of TEs, perhaps triggered by interspecific hybridization.
[Show abstract][Hide abstract] ABSTRACT: The evolutionary history of chromosomes can be tracked by the comparative hybridization of large panels of bacterial artificial chromosome clones. This approach has disclosed an unprecedented phenomenon: 'centromere repositioning', that is, the movement of the centromere along the chromosome without marker order variation. The occurrence of evolutionary new centromeres (ENCs) is relatively frequent. In macaque, for instance, 9 out of 20 autosomal centromeres are evolutionarily new; in donkey at least 5 such neocentromeres originated after divergence from the zebra, in less than 1 million years. Recently, orangutan chromosome 9, considered to be heterozygous for a complex rearrangement, was discovered to be an ENC. In humans, in addition to neocentromeres that arise in acentric fragments and result in clinical phenotypes, 8 centromere-repositioning events have been reported. These 'real-time' repositioned centromere-seeding events provide clues to ENC birth and progression. In the present paper, we provide a review of the centromere repositioning. We add new data on the population genetics of the ENC of the orangutan, and describe for the first time an ENC on the X chromosome of squirrel monkeys. Next-generation sequencing technologies have started an unprecedented, flourishing period of rapid whole-genome sequencing. In this context, it is worth noting that these technologies, uncoupled from cytogenetics, would miss all the biological data on evolutionary centromere repositioning. Therefore, we can anticipate that classical and molecular cytogenetics will continue to have a crucial role in the identification of centromere movements. Indeed, all ENCs and human neocentromeres were found following classical and molecular cytogenetic investigations.
[Show abstract][Hide abstract] ABSTRACT: Structural variation has played an important role in the evolutionary restructuring of human and great ape genomes. Recent analyses have suggested that the genomes of chimpanzee and human have been particularly enriched for this form of genetic variation. Here, we set out to assess the extent of structural variation in the gorilla lineage by generating 10-fold genomic sequence coverage from a western lowland gorilla and integrating these data into a physical and cytogenetic framework of structural variation. We discovered and validated over 7665 structural changes within the gorilla lineage, including sequence resolution of inversions, deletions, duplications, and mobile element insertions. A comparison with human and other ape genomes shows that the gorilla genome has been subjected to the highest rate of segmental duplication. We show that both the gorilla and chimpanzee genomes have experienced independent yet convergent patterns of structural mutation that have not occurred in humans, including the formation of subtelomeric heterochromatic caps, the hyperexpansion of segmental duplications, and bursts of retroviral integrations. Our analysis suggests that the chimpanzee and gorilla genomes are structurally more derived than either orangutan or human genomes.
Genome Research 06/2011; 21(10):1640-9. DOI:10.1101/gr.124461.111 · 14.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Cytogenetic studies showed that a number of New World primate taxa, particularly the genera Alouatta, Aotus, and Callicebus, have highly derived karyotypes. Cytogenetics in these primates, at every level of analysis, has contributed to the recognition of species and revealed that their number was certainly underestimated by researchers relying solely on traditional morphological data. Further attention was drawn to Alouatta and Aotus because they are characterized by translocations of the Y chromosome to autosomes, generating multiple sex chromosome systems. Here we present a report on the hybridization of human chromosome-specific paints on metaphases from 4 individuals originally assigned to Alouatta caraya and 1 individual of Aotuslemurinus. This is only the third karyotype studied with chromosome painting out of more than 10 known karyomorphs in Aotus. The banded chromosomes matched those of karyotype II as defined by Ma et al. [1976a], and we were able to more precisely assign the origin of the sample to A. l. griseimembra. Our results on the Argentinean Alouatta caraya samples were generally comparable to the banding and hybridization pattern of previous studies of A. caraya including the presence of an X(1)X(1)X(2)X(2)/X(1)X(2)Y(1)Y(2) sex chromosome system. The karyotype of the Brazilian Alouatta sample labeled as A. caraya differs from the 3 Argentinean samples by at least 10 chromosome rearrangements. The diploid number, G banding, and hybridization pattern of this female cell line was almost identical to previous painting results on Alouatta guariba guariba. Therefore we must conclude that this cell line is actually from an A. guariba guariba individual. The contribution of cytogenetic tools in identifying species or in this case assigning individuals or cell lines to their precise taxonomic allocation is stressed. Gathering further molecular cytogenetic data on New World primates should be conservation and management priorities.
Cytogenetic and Genome Research 02/2011; 134(1):40-50. DOI:10.1159/000324415 · 1.56 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: 'Orang-utan' is derived from a Malay term meaning 'man of the forest' and aptly describes the southeast Asian great apes native to Sumatra and Borneo. The orang-utan species, Pongo abelii (Sumatran) and Pongo pygmaeus (Bornean), are the most phylogenetically distant great apes from humans, thereby providing an informative perspective on hominid evolution. Here we present a Sumatran orang-utan draft genome assembly and short read sequence data from five Sumatran and five Bornean orang-utan genomes. Our analyses reveal that, compared to other primates, the orang-utan genome has many unique features. Structural evolution of the orang-utan genome has proceeded much more slowly than other great apes, evidenced by fewer rearrangements, less segmental duplication, a lower rate of gene family turnover and surprisingly quiescent Alu repeats, which have played a major role in restructuring other primate genomes. We also describe a primate polymorphic neocentromere, found in both Pongo species, emphasizing the gradual evolution of orang-utan genome structure. Orang-utans have extremely low energy usage for a eutherian mammal, far lower than their hominid relatives. Adding their genome to the repertoire of sequenced primates illuminates new signals of positive selection in several pathways including glycolipid metabolism. From the population perspective, both Pongo species are deeply diverse; however, Sumatran individuals possess greater diversity than their Bornean counterparts, and more species-specific variation. Our estimate of Bornean/Sumatran speciation time, 400,000 years ago, is more recent than most previous studies and underscores the complexity of the orang-utan speciation process. Despite a smaller modern census population size, the Sumatran effective population size (N(e)) expanded exponentially relative to the ancestral N(e) after the split, while Bornean N(e) declined over the same period. Overall, the resources and analyses presented here offer new opportunities in evolutionary genomics, insights into hominid biology, and an extensive database of variation for conservation efforts.
[Show abstract][Hide abstract] ABSTRACT: Molecular cytogenetics provides a visual, pictorial record of the tree of life, and in this respect the fusion origin of human chromosome 2 is a well-known paradigmatic example. Here we report on a variant chromosome 6 in which the centromere jumped to 6p22.1. ChIP-chip experiments with antibodies against the centromeric proteins CENP-A and CENP-C exactly defined the neocentromere as lying at chr6:26,407-26,491 kb. We investigated in detail the evolutionary history of chromosome 6 in primates and found that the primate ancestor had a homologous chromosome with the same marker order, but with the centromere located at 6p22.1. Sometime between 17 and 23 million years ago (Mya), in the common ancestor of humans and apes, the centromere of chromosome 6 moved from 6p22.1 to its current location. The neocentromere we discovered, consequently, has jumped back to the ancestral position, where a latent centromere-forming potentiality persisted for at least 17 Myr. Because all living organisms form a tree of life, as first conceived by Darwin, evolutionary perspectives can provide compelling underlying explicative grounds for contemporary genomic phenomena.
Genome Research 06/2009; 19(5):778-84. DOI:10.1101/gr.085688.108 · 14.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The centromere has a pivotal role in structuring chromosomal architecture, but remains a poorly understood and seemingly paradoxical "black hole." Centromeres are a very rapidly evolving segment of the genome and it is now known that centromere shifts in evolution are not rare and must be considered on a par with other chromosome rearrangements. Recently, unprecedented findings on neocentromeres and evolutionary new centromeres (ENC) have helped clarify the relationship of the centromere within the genome and shown that these two phenomena are two faces of the same coin. No prominent sequence features are known that promote centromere formation and both types of new centromeres are formed epigenetically, both clinical neocentromeres and ENC cluster at chromosomal "hotspots." The clustering of neocentromeres in 8p is probably the result of the relatively high frequency of noncanonical pairing. Studies on the evolution of the chromosomes 3, 13, and 15 help explain why there are clusters of neocentromeres. These domains often correspond to ancestral inactivated centromeres and some regions can preserve features that trigger neocentromere emergence over tens of millions of years. Neocentromeres may be correlated with the distribution of segmental duplications (SDs) in regions of extreme plasticity that often can be characterized as gene deserts. Further, because centromeres and associated pericentric regions are dynamically complex, centromere shifts may turbocharge genome reorganization by influencing the distribution of heterochromatin. The "reuse" of regions as centromere seeding-points in evolution and in human clinical cases further extends the concept of "reuse" of specific domains for "chromosomal events."
Progress in molecular and subcellular biology 02/2009; 48:103-52. DOI:10.1007/978-3-642-00182-6_5
[Show abstract][Hide abstract] ABSTRACT: We have compared the synteny block organization of the official macaque genome sequence assembly (Jan. 2006; rheMac2) with an independent assembly that used a molecular cytogenetic approach. The mapping of four synteny segments, ranging in size from 4 Mb to 24 Mb, was found to be inconsistent between the two datasets. We specifically investigated these discrepancies by appropriate co-hybridization FISH experiments with validated reference probes located outside the area under study. We found that in the macaque rheMac2 release three synteny segments were wrongly mapped and one segment was incorrectly oriented.
Chromosome Research 11/2008; 16(7):977-85. DOI:10.1007/s10577-008-1255-1 · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this study we characterized the extension, reciprocal arrangement, and orientation of syntenic chromosomal segments in the lar gibbon (Hylobates lar, HLA) by hybridization of a panel of approximately 1000 human BAC clones. Each lar gibbon rearrangement was defined by a splitting BAC clone or by two overlapping clones flanking the breakpoint. A reconstruction of the synteny arrangement of the last common ancestor of all living lesser apes was made by combining these data with previous results in Nomascus leucogenys, Hoolock hoolock, and Symphalangus syndactylus. The definition of the ancestral synteny organization facilitated tracking the cascade of chromosomal changes from the Hominoidea ancestor to the present day karyotype of Hylobates and Nomascus. Each chromosomal rearrangement could be placed within an approximate phylogenetic and temporal framework. We identified 12 lar-specific rearrangements and five previously undescribed rearrangements that occurred in the Hylobatidae ancestor. The majority of the chromosomal differences between lar gibbons and humans are due to rearrangements that occurred in the Hylobatidae ancestor (38 events), consistent with the hypothesis that the genus Hylobates is the most recently evolved lesser ape genus. The rates of rearrangements in gibbons are 10 to 20 times higher than the mammalian default rate. Segmental duplication may be a driving force in gibbon chromosome evolution, because a consistent number of rearrangements involves pericentromeric regions (10 events) and centromere inactivation (seven events). Both phenomena can be reasonably supposed to have strongly contributed to the euchromatic dispersal of segmental duplications typical of pericentromeric regions. This hypothesis can be more fully tested when the sequence of this gibbon species becomes available. The detailed synteny map provided here will, in turn, substantially facilitate sequence assembly efforts.
Genome Research 07/2008; 18(9):1530-7. DOI:10.1101/gr.078295.108 · 14.63 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A young girl with 46, XX, r(18)/46, XX/45, XX, –18 chromosome constitution is reported. She displays a slight degree of mental retardation. The line with the ring chromosome predominates in blood lymphocytes. In skin fibroblast culture the ring(18) line showed a constant decreasing trend, from 45% at the first passage, down to its disappearance at the 19th passage, where only 46, XX cells were observed. The child/mid parents' ratio of Peptidase A activity in red cells was 0.36. The Peptidase A activity in a fibroblast clone 46, XX, r(l 8) was 0.55 compared to the 46, XX line. These data suggest that the PEP A locus was lost in ring formation.
[Show abstract][Hide abstract] ABSTRACT: Chromosomal rearrangements, such as translocations and inversions, are recurrent phenomena during evolution, and both of them are involved in reproductive isolation and speciation. To better understand the molecular basis of chromosome rearrangements and their part in karyotype evolution, we have investigated the history of human chromosome 17 by comparative fluorescence in situ hybridization (FISH) and sequence analysis.
Human bacterial artificial chromosome/p1 artificial chromosome probes spanning the length of chromosome 17 were used in FISH experiments on great apes, Old World monkeys and New World monkeys to study the evolutionary history of this chromosome. We observed that the macaque marker order represents the ancestral organization. Human, chimpanzee and gorilla homologous chromosomes differ by a paracentric inversion that occurred specifically in the Homo sapiens/Pan troglodytes/Gorilla gorilla ancestor. Detailed analyses of the paracentric inversion revealed that the breakpoints mapped to two regions syntenic to human 17q12/21 and 17q23, both rich in segmental duplications.
Sequence analyses of the human and macaque organization suggest that the duplication events occurred in the catarrhine ancestor with the duplication blocks continuing to duplicate or undergo gene conversion during evolution of the hominoid lineage. We propose that the presence of these duplicons has mediated the inversion in the H. sapiens/P. troglodytes/G. gorilla ancestor. Recently, the same duplication blocks have been shown to be polymorphic in the human population and to be involved in triggering microdeletion and duplication in human. These results further support a model where genomic architecture has a direct role in both rearrangement involved in karyotype evolution and genomic instability in human.
[Show abstract][Hide abstract] ABSTRACT: In 1992 the Japanese macaque was the first species for which the homology of the entire karyotype was established by cross-species chromosome painting. Today, there are chromosome painting data on more than 50 species of primates. Although chromosome painting is a rapid and economical method for tracking translocations, it has limited utility for revealing intrachromosomal rearrangements. Fortunately, the use of BAC-FISH in the last few years has allowed remarkable progress in determining marker order along primate chromosomes and there are now marker order data on an array of primate species for a good number of chromosomes. These data reveal inversions, but also show that centromeres of many orthologous chromosomes are embedded in different genomic contexts. Even if the mechanisms of neocentromere formation and progression are just beginning to be understood, it is clear that these phenomena had a significant impact on shaping the primate genome and are fundamental to our understanding of genome evolution. In this report we complete and integrate the dataset of BAC-FISH marker order for human syntenies 1, 2, 4, 5, 8, 12, 17, 18, 19, 21, 22 and the X. These results allowed us to develop hypotheses about the content, marker order and centromere position in ancestral karyotypes at five major branching points on the primate evolutionary tree: ancestral primate, ancestral anthropoid, ancestral platyrrhine, ancestral catarrhine and ancestral hominoid. Current models suggest that between-species structural rearrangements are often intimately related to speciation. Comparative primate cytogenetics has become an important tool for elucidating the phylogeny and the taxonomy of primates. It has become increasingly apparent that molecular cytogenetic data in the future can be fruitfully combined with whole-genome assemblies to advance our understanding of primate genome evolution as well as the mechanisms and processes that have led to the origin of the human genome.
Chromosome Research 02/2008; 16(1):17-39. DOI:10.1007/s10577-007-1209-z · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Author Summary
Centromeric DNA has been described as the last frontier of genomic sequencing; such regions are typically poorly assembled during the whole-genome shotgun sequence assembly process due to their repetitive complexity. This paper develops a computational algorithm to systematically extract data regarding primate centromeric DNA structure and organization from that ∼5% of sequence that is not included as part of standard genome sequence assemblies. Using this computational approach, we identify and reconstruct published human higher-order alpha satellite arrays and discover new families in human, chimpanzee, and Old World monkeys. Experimental validation confirms the utility of this computational approach to understanding the centromere organization of other nonhuman primates. An evolutionary analysis in diverse primate genomes supports fundamental differences in the structure and organization of centromere DNA between ape and Old World monkey lineages. The ability to extract meaningful biological data from random shotgun sequence data helps to fill an important void in large-scale sequencing of primate genomes, with implications for other genome sequencing projects.