Robert D. Bradley's research while affiliated with Texas Tech University and other places

Publications (170)

Article
Guidelines identifying best practices for harvesting tissues that lead to optimal DNA preservation are few but are important curatorial concerns for genetic resource collections. We conducted a temporal study to establish rate of DNA degradation of tissue samples extracted from field-caught museum specimens. Five individuals of Sigmodon hispidus we...
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Species with low effective population sizes are at greater risk of extinction because of reduced genetic diversity. Such species are more vulnerable to chance events that decrease population sizes (e.g. demographic stochasticity). Dipodomys elator, (Texas kangaroo rat) is a kangaroo rat that is classified as threatened in Texas and field surveys fr...
Preprint
A bstract We describe a non-invasive blood test that exploits differences in the abundance of diagnostic miRNA biomarkers associated with prion infections in cervids. Three potentially diagnostic and two control miRNAs were amplified in 93 serum samples from pen-raised whitetailed deer exposed to Chronic Wasting Disease (CWD). Initial analyses reve...
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Background Speciation genes contribute disproportionately to species divergence, but few examples exist, especially in vertebrates. Here we test whether Zan , which encodes the sperm acrosomal protein zonadhesin that mediates species-specific adhesion to the egg’s zona pellucida, is a speciation gene in placental mammals. Results Genomic ontogeny...
Article
Odocoileus virginianus (white-tailed deer) and O. hemionus (mule deer) are sympatric across much of North America. Molecular evidence suggests that up to 24% of individuals in some populations are a product of hybrid ancestry. Several studies have alluded to ancient and recent introgression between Odocoileus spp.; however, no divergence dates were...
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Specimens of the Peromyscus boylii species group distributed in the western and northeastern montane regions of Michoacán, México, historically have been assigned to P. levipes. Previous studies indicated that these specimens possessed mitochondrial DNA haplotypes that were distinct from both P. levipes and P. kilpatricki, a recently named species...
Book
One hundred fifty years ago, Texas was very different. A rural population was spread thinly across the eastern and central parts of the state, and vast lands in the western regions were still undisturbed. Texas’s habitats and biota changed dramatically as its population increased and people spread across the landscape. In Texas Natural History: A...
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Translocation records indicate aoudad (Ammotragus lervia) populations in the United States are a product of multiple human-mediated introductions. Two mitochondrial markers (cytochrome b, cytb; displacement loop, D loop) and one nuclear gene (prion protein gene exon 3, PRNP) were used to determine: (1) genetic variation, (2) if genetic units corres...
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To investigate the distribution of Microtus ochrogaster (Prairie Voles) in the Texas Pan-handle, owl pellets were collected from 123 owl roosts in 27 counties. Remains of Prairie Voles were found at 76 roosts in 20 counties. Fifty-four of the roost sites (located in Briscoe, and Swisher counties) represent new county records for M. ochrogaster in T...
Article
The woodrats or packrats of the genus Neotoma have been the subject of a wide array of research including paleoecology, physiology, morphological evolution, systematics, speciation, and hybridization. In recent years, much work has been done to elucidate evolutionary relationships within and between closely related species of the genus; in particul...
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Grand Manan Island represents the southernmost region of the province of New Brunswick, Canada. Due to its isolation, the island fauna is depauperate, with few native mammal species. Recent molecular genetic analysis of Peromyscus collected from GMI revealed the mitotype (cytochrome b gene) indicative of P. leucopus (White-footed Deermouse). This s...
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Conservation research concerning rare species can be arduous. At the same time, assessing the genetic characteristics of a population is critical for informing conservation and management strategies. For species that are rare or threatened, researchers must balance the well-being of the animal and its population size with the need to acquire adequa...
Preprint
Full-text available
Organisms with low effective population sizes are at greater risk of extinction because of reduced genetic diversity. Dipodomys elator is a kangaroo rat that is classified as threatened in Texas and field surveys from the past 50 years indicate that the distribution of this species has decreased. This suggests geographic range reductions that could...
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To determine the extent of genetic introgression along the parapatric border between Neotoma floridana and N. micropus, 140 woodrats were sampled from 21 localities in Kansas, Oklahoma, and Texas, at varying distances from the proposed species boundaries. All individuals were examined at the mitochondrial cytochrome-b gene (Cytb) and two nuclear in...
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Frozen tissues, associated with natural history and biological collections, historically have been archived at temperatures between −20°C and −80°C. More recently, the availability of liquid nitrogen systems has enabled the storage of tissue samples (biobanking) at temperatures as low as −196°C. Currently, it is not known how the degree of coldness...
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Axis deer (Axis axis) occur both in captivity and free-ranging populations in portions of North America, but to-date, no data exist pertaining to the species’ susceptibility to CWD. We sequenced the prion protein gene (PRNP) from axis deer. We then compared axis deer PrPC sequences and amino acid polymorphisms to those of CWD susceptible species. A...
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Mauldin et al. (2014) examined 103 woodrats collected in 1988 from a putative contact zone located in Major County, Oklahoma, and provided evidence for a substantial level of hybridization between Neotoma floridana and N. micropus. This site was resampled in 2010, with 42 woodrats collected, and again in 2011, when an additional 88 woodrats were co...
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Herein, 62 county records are reported for 20 species of mammals from 57 Texas counties and include records from six different mammalian orders: Cingulata, Lagomorpha, Soricomor-pha, Chiroptera, Carnivora, and Rodentia. Although many of these records serve to fill gaps in expected distributions, others represent range extensions, as in Peromyscus g...
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The emergence of several zoonotically-driven pandemics and near-pandemics (MERS, SARS, H1N1, Ebola, COVID-19, among others) over the last 20 years has placed an increasing emphasis on the importance of symbiotypes and the role of natural history collections, as virologic and human health studies are incorporating symbiotypes and host specimens as p...
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The genus Peromyscus represents a rapidly diverged clade of Cricetid rodents that contains multiple cryptic species and has a propensity for morphologic conservation across its members. The unresolved relationships in previously proposed phylogenies reflect a suspected rapid adaptive radiation. To identify functional groups of genes that may be imp...
Chapter
Introduction to the 911 page book entitled "From field to laboratory: a memorial volume in honor of Robert J. Baker."
Chapter
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This article describes Robert James Baker’s academic pedigree and genealogy, his scientific productivity (number of publications), his citations, his students, his contributions to his university and scientific societies, his personality in relation to his scientific achievements, his legacy, and a personal note of appreciation by individuals who w...
Chapter
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Nine Zoogeographic Units (ZU) have been hypothesized for Ecuador, with seven of these units located within the continental portion of the country. Each ZU was defined by climate, topography, elevation, and vegetation type. In spite of their historical ap- plication, the validity of ZUs has not been tested. The goal of the present study was to treat...
Article
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This article describes Robert James Baker’s academic pedigree and genealogy, his scientific productivity (number of publications), his citations, his students, his contributions to his university and scientific societies, his personality in relation to his scientific achievements, his legacy, and a personal note of appreciation by individuals who w...
Article
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Introduction to the memorial volume of Special Publications / Museum of Texas Tech University in honor of Robert J. Baker. First paragraph: Herein, we use the word “Overture” not in its first meaning, but rather in its second—“An introduction to something more substantial” ([Def. 2], Oxford Dictionaries, Oxford University Press 2018). In our curren...
Chapter
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Texas is home to more wind turbines and more bat species than any other state in the United States. Insectivorous bats provide an important economical ecosystem service in this region through agricultural pest regulation. Unfortunately, bats can be impacted negatively by wind turbines, and migratory bat species particularly so. To understand how ba...
Chapter
The Rio Grande ground squirrel (Ictidomys parvidens) and the thirteen-lined ground squirrel (I. tridecemlineatus) form a mosaic hybrid zone across portions of New Mexico and Texas. Recent studies have linked habitat modification to the formation of secondary contact; however, it has been suggested that ancient hybridization was a result of climate...
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As a periodic assessment of the mammal collection resource, the Systematic Collections Committee (SCC) of the American Society of Mammalogists undertakes decadal surveys of the collections held in the Western Hemisphere. The SCC surveyed 429 collections and compiled a directory of 395 active collections containing 5,275,155 catalogued specimens. Ov...
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Dromedary camels (Camelus dromedarius) are a domesticated and closely guarded economic staple of indigenous people located throughout Ethiopian territorial states. Seventeen morphometric variables were examined to determine intraspecific variation among 8 pastoralist-designated breeds of camels. Additionally, DNA sequences from mitochondrial cytoch...
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First paragraph: On 30 March 2018, the science of mammalogy and the American Society of Mammalogists lost one of the most influential figures of the last half-century. Robert James Baker died quietly at his home in Lubbock, Texas (Fig. 1). He was born on 8 April 1942 to James Simeon Baker and Laura Cooper in Warren, Arkansas. His father was killed...
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On 30 March 2018, the science of mammalogy and the American Society of Mammalogists lost one of the most influential figures of the last half-century. Robert James Baker died quietly at his home in Lubbock, Texas.
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An allopatric population of big-eared climbing rats (Ototylomys) from the Northern Highlands of Chiapas, Mexico, is described as a new species. The new taxon is part of a unique montane rainforest community that includes several other endemic species in the limited geographic range between the Río Grijalva and the Central Depression of Chiapas. Sev...
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Background Recent phylogenies of deer mice, genus Peromyscus, have relied heavily on mitochondrial markers. These markers provided resolution at and below the level of species groups, but relationships among species groups and Peromyscus affiliated genera have received little support. Here, we present the mitochondrial genomes of 14 rodents and inf...
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Elk (Cervus canadensis) historically are among the most widely distributed members of the deer family, occupying much of the United States, Canada, and northern Mexico. The natural distribution of this species decreased substantially in the early 20 th century, presumably resulting in the extirpation of populations in Texas. In the past 40 years, s...
Article
The broad objective of this study was to increase our knowledge of Muleshoe virus and other hantaviruses associated with cricetid rodents in Texas. Anti-hantavirus antibody was found in 38 (3.2%) of 1171 neotomine rodents and 6 (1.8%) of 332 sigmodontine rodents from 10 Texas counties; hantaviral RNA was detected in 23 (71.9%) of 32 antibody-positi...
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The taxonomic status of Peromyscus nudipes has been problematic, with morphometric studies placing P. nudipes in synonymy with P. mexicanus, whereas molecular studies have indicated that P. nudipes may be an independent evolutionary lineage. To address this conundrum, DNA sequences from the mitochondrial cytochrome-b gene, representing all but one...
Article
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Specimens of the Peromyscus boylii species group occurring in the montane regions of Michoacán, México, historically have been assigned to P. levipes. However, previous studies have shown that some specimens from eastern Michoacán possessed mitochondrial DNA haplotypes and karyotypes that were distinct from P. levipes and other members of the P. bo...
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Recent biological surveys resulted in new county records of mammalian species in Texas. Efforts resulted in 16 county records of 12 species of mammals in 10 counties (Archer, Childress, Erath, Foard, Gregg, Kimble, Lubbock, Panola, Rockwall, and Smith). These records supplement information regarding occurrence and distribution of mammalian species...
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Temporal effects on genetic diversity were investigated within a large, panmictic population of Southern Plains Woodrats (Neotoma micropus). Microsatellite genotypes obtained from 549 individuals, collected during a 4-year period, were assigned to groups according to capture site and year of capture. Most (99.84%) of the genetic variation was attri...
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DNA sequences from the mitochondrial cytochrome-b gene were obtained from 41 specimens of Neotoma albigula from the southwestern United States and northwestern México. Phylogenetic analyses depicted that samples of N. a. melanura from southern Sonora and northern Sinaloa formed a clade separate from representatives of the other sampled subspecies o...
Article
The sister species Ictidomys parvidens and I. tridecemlineatus exhibit hybridization in southeastern New Mexico and western Texas. Presumably, hybridization was due to secondary contact as a result of recent anthropogenic changes to the landscape. However, recent phyloge- netic studies of Spermophilus, which previously included Ictidomys, indicated...
Article
The evolutionary relationships between Peromyscus, Habromys, Isthmomys, Megadontomys, Neotomodon, Osgoodomys, and Podomys are poorly understood. In order to further explore the evolutionary boundaries of Peromyscus and compare potential taxonomic solutions for this diverse group and its relatives, we conducted phylogenetic analyses of DNA sequence...
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The objective of this study was to advance our knowledge of the epizootiology of Bear Canyon virus and other Tacaribe serocomplex viruses (Arenaviridae) associated with wild rodents in California. Antibody (immunoglobulin G [IgG]) to a Tacaribe serocomplex virus was found in 145 (3.6%) of 3977 neotomine rodents (Cricetidae: Neotominae) captured in...
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Mammal trapping efforts were conducted during the summer and fall of 2014 at sites in five counties in Texas (Delta, Fayette, Hopkins, Lubbock, and Dickens). These efforts resulted in 18 county records involving: one soricomorph, one chiropteran, one lagomorph, one cingulate, and ten species of rodents. The species record for Microtus extends the r...
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Natural history collections serve as important sources of biological data for scientists, educators, and the general public. These collections are a crucial cornerstone for systematics, natural history, ecology, and many other specialized disciplines, whose research depends on either the specimen or the associated data. Recent studies have provided...
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The Checklist of North American Mammals North of Mexico, 2003 has been revised to include recent taxonomic changes and additions, as well as to include new distribution records and introductions for this region. In this revision, 495 species, 180 genera, 48 families, and 12 orders are recognized, resulting in a net gain of 21 species, 14 genera, an...
Article
Analyses of the mitochondrial cytochrome-b gene were used to determine levels of genetic differentiation and patterns of relationship among members of the Neotoma mexicana (Mexican woodrat) species group in Mesoamerica. Three well-supported clades were obtained that conform to the species N. ferruginea Tomes, 1862, N. mexicana Baird, 1855, and N. p...
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Natural history specimens and their associated data are a valuable resource to the scientific and educational communities, with each specimen representing a unique sample from a specific locality and a specific point in time. Given this intrinsic value to research and education, a few studies have attempted to assign a monetary value or worth to sp...
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In order to investigate hybridization between 2 species of woodrats, Neotoma floridana and Neotoma micropus, 103 specimens were collected, in March of 1988, from a known area of sympatry, and compared with reference collections from areas of allopatry. Ten genetic markers, consisting of 7 microsatellite loci, 1 mitochondrial gene (cytochrome-b [Cyt...
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Peromyscus grandis is a rodent whose distribution is restricted to the mountain ranges of central Guatemala. This note represents the first report of karyotypic data for this species. The karyotype (fundamental number = 58) closely resembles karyotypes of other species of Peromyscus.
Article
Recovery efforts for the endangered ocelot (Leopardus pardalis) would be aided by knowledge of its feeding ecology in the affected region. We analyzed scat of ocelots and bobcats (Lynx rufus) from southern Texas. As has been found for most other populations of ocelots, rodents were the primary prey, but the principal species of rodent, the Mexican...