Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 43
Filter
Add more filters










Publication year range
1.
Genes (Basel) ; 12(8)2021 08 11.
Article in English | MEDLINE | ID: mdl-34440410

ABSTRACT

Since the 19th century, the addax (Addax nasomaculatus) has lost approximately 99% of its former range. Along with its close relatives, the blue antelope (Hippotragus leucophaeus) and the scimitar-horned oryx (Oryx dammah), the addax may be the third large African mammal species to go extinct in the wild in recent times. Despite this, the evolutionary history of this critically endangered species remains virtually unknown. To gain insight into the population history of the addax, we used hybridization capture to generate ten complete mitochondrial genomes from historical samples and assembled a nuclear genome. We found that both mitochondrial and nuclear diversity are low compared to other African bovids. Analysis of mitochondrial genomes revealed a most recent common ancestor ~32 kya (95% CI 11-58 kya) and weak phylogeographic structure, indicating that the addax likely existed as a highly mobile, panmictic population across its Sahelo-Saharan range in the past. PSMC analysis revealed a continuous decline in effective population size since ~2 Ma, with short intermediate increases at ~500 and ~44 kya. Our results suggest that the addax went through a major bottleneck in the Late Pleistocene, remaining at low population size prior to the human disturbances of the last few centuries.


Subject(s)
Antelopes/classification , Endangered Species , Extinction, Biological , Animals , Antelopes/genetics , Biodiversity , Genome, Mitochondrial , Hybridization, Genetic , Phylogeography
2.
Parasitology ; 148(6): 740-746, 2021 05.
Article in English | MEDLINE | ID: mdl-33536088

ABSTRACT

Parasite surveys were conducted for 1­2 years in the Kruger National Park (KNP), South Africa on blue wildebeest, impalas, greater kudus, common warthogs and scrub hares. The host associations of some of the gastrointestinal nematode species infecting ≥60% of at least one of the five host species, were determined. These were Agriostomum gorgonis, Cooperia acutispiculum, Cooperia connochaeti, Cooperia hungi, Cooperia neitzi, Cooperioides hamiltoni, Gaigeria pachyscelis, Haemonchus bedfordi, Haemonchus krugeri, Haemonchus vegliai, Impalaia tuberculata, Longistrongylus sabie, Strongyloides papillosus, Trichostrongylus deflexus and Trichostrongylus thomasi. Although the prevalence of Trichostrongylus falculatus did not exceed 50% in any host species, it was present in all five hosts. Nematodes in the KNP range from those exhibiting strict host associations to generalists. Nematode-host associations may be determined by host feeding patterns and habitat use. Eight ixodid tick species were commonly collected from the same animals and in 2­3 year long surveys from plains zebras and helmeted guinea fowls: Amblyomma hebraeum, Amblyomma marmoreum, Hyalomma truncatum, Rhipicephalus appendiculatus, Rhipicephalus decoloratus, Rhipicephalus evertsi evertsi, Rhipicephalus simus and Rhipicephalus zambeziensis. Host specificity was less pronounced in ixodid tick species than in nematodes and the immature stages of five tick species infested all host species examined.


Subject(s)
Animals, Wild/parasitology , Ixodidae/classification , Nematode Infections/veterinary , Tick Infestations/veterinary , Animals , Antelopes/classification , Antelopes/parasitology , Equidae/parasitology , Galliformes/parasitology , Hares/parasitology , Host-Parasite Interactions , Nematode Infections/epidemiology , Nematode Infections/parasitology , South Africa/epidemiology , Swine/parasitology , Tick Infestations/epidemiology , Tick Infestations/parasitology
3.
Sci Rep ; 11(1): 3152, 2021 02 04.
Article in English | MEDLINE | ID: mdl-33542477

ABSTRACT

Chromosome structural change has long been considered important in the evolution of post-zygotic reproductive isolation. The premise that karyotypic variation can serve as a possible barrier to gene flow is founded on the expectation that heterozygotes for structurally distinct chromosomal forms would be partially sterile (negatively heterotic) or show reduced recombination. We report the outcome of a detailed comparative molecular cytogenetic study of three antelope species, genus Raphicerus, that have undergone a rapid radiation. The species are largely conserved with respect to their euchromatic regions but the X chromosomes, in marked contrast, show distinct patterns of heterochromatic amplification and localization of repeats that have occurred independently in each lineage. We argue a novel hypothesis that postulates that the expansion of heterochromatic blocks in the homogametic sex can, with certain conditions, contribute to post-zygotic isolation. i.e., female hybrid incompatibility, the converse of Haldane's rule. This is based on the expectation that hybrids incur a selective disadvantage due to impaired meiosis resulting from the meiotic checkpoint network's surveillance of the asymmetric expansions of heterochromatic blocks in the homogametic sex. Asynapsis of these heterochromatic regions would result in meiotic silencing of unsynapsed chromatin and, if this persists, germline apoptosis and female infertility.


Subject(s)
Antelopes/genetics , Genetic Speciation , Karyotype , Models, Genetic , Reproductive Isolation , X Chromosome/ultrastructure , Africa , Animals , Antelopes/classification , Female , Gene Flow , Heterozygote , Hybridization, Genetic , In Situ Hybridization, Fluorescence , Infertility, Female/genetics , Male , Meiosis , Recombination, Genetic , Sex Factors
4.
Mol Biol Rep ; 48(2): 1255-1268, 2021 Feb.
Article in English | MEDLINE | ID: mdl-33555530

ABSTRACT

Blackbuck (Antilope cervicapra) is a threatened species endemic to the Indian subcontinent. Many populations of blackbuck are found in southern India. Populations of blackbuck are negatively affected in many places for various reasons, such as habitat destruction and poaching. Their range decreased sharply during the 20th century. There is very limited information available on the population dynamics of blackbuck in southern India. For the phylogenetic and genetic diversity analyses of blackbuck populations among different distribution ranges in southern India, we sequenced mt DNA of cytochrome b (Cyt b) for 120, cytochrome c oxidase subunit-1 (COI) for 137 and the control region (CR) for 137 fecal pellets from eleven different locations in southern India. We analyzed the genetic structure of three mitochondrial markers, the CR, Cyt b and the COI region, separately and in a combined dataset. The haplotype diversity and nucleotide diversity of CR were 0.969 and 0.047, respectively, and were higher than those of Cyt b and COI. A Bayesian phylogeny and an MJ network based on the CR and combined dataset (105 sequences) signified several distinct haplotype clusters within blackbuck, whereas no clusters were identified with the Cyt b and COI phylogenetic analyses. The analysis of molecular variance of the combined data set revealed 52.46% genetic variation within the population. Mismatch distribution analysis revealed that blackbuck populations underwent complex changes with analysis of the combined dataset in each population and analysis of each marker separately in the overall population. The results provide evidence that blackbuck in different geographic locations has a distinct population structure due to habitat fragmentation after the formation of the Western and Eastern Ghats.


Subject(s)
Antelopes/genetics , Cytochromes b/genetics , Genetic Variation/genetics , Population Dynamics , Animals , Antelopes/classification , DNA, Mitochondrial/genetics , Ecosystem , Endangered Species , Haplotypes/genetics , India , Phylogeny
5.
Sci Rep ; 11(1): 2100, 2021 01 22.
Article in English | MEDLINE | ID: mdl-33483538

ABSTRACT

Native to southern Africa, the blue antelope (Hippotragus leucophaeus) is the only large African mammal species known to have become extinct in historical times. However, it was poorly documented prior to its extinction ~ 1800 AD, and many of the small number of museum specimens attributed to it are taxonomically contentious. This places limitations on our understanding of its morphology, ecology, and the mechanisms responsible for its demise. We retrieved genetic information from ten of the sixteen putative blue antelope museum specimens using both shotgun sequencing and mitochondrial genome target capture in an attempt to resolve the uncertainty surrounding the identification of these specimens. We found that only four of the ten investigated specimens, and not a single skull, represent the blue antelope. This indicates that the true number of historical museum specimens of the blue antelope is even smaller than previously thought, and therefore hardly any reference material is available for morphometric, comparative and genetic studies. Our study highlights how genetics can be used to identify rare species in natural history collections where other methods may fail or when records are scarce. Additionally, we present an improved mitochondrial reference genome for the blue antelope as well as one complete and two partial mitochondrial genomes. A first analysis of these mitochondrial genomes indicates low levels of maternal genetic diversity in the 'museum population', possibly confirming previous results that blue antelope population size was already low at the time of the European colonization of South Africa.


Subject(s)
Animal Distribution , Antelopes/genetics , Extinction, Biological , Genome, Mitochondrial/genetics , Animals , Antelopes/classification , Antelopes/physiology , Conservation of Natural Resources , DNA, Mitochondrial/chemistry , DNA, Mitochondrial/genetics , Genetic Variation , Museums , Phylogeny , Population Density , Population Dynamics , Sequence Analysis, DNA , South Africa , Species Specificity
6.
Zoo Biol ; 39(2): 129-140, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31904139

ABSTRACT

The original North American ex situ wildebeest population was believed to originate from the white-bearded wildebeest (Connochaetes taurinus albojubatus), which is both morphologically distinct and geographically separated from the brindled wildebeest (C. t. taurinus). However, after an import of wildebeest into North America in 2001, managers have suspected that white-bearded and brindled wildebeest were mixed in herds at multiple institutions. We sequenced the mitochondrial control region (d-loop) from a portion of the managed North American population and compared our sequences with previously published sequences from wild individuals to determine the subspecific identity and genetic diversity of our ex situ population. We were able to confidently identify C. t. albojubatus as the subspecies identity of the sampled portion of our population. Within our population, haplotype and nucleotide diversity were low (0.169 and 0.001, respectively) with a single common haplotype (H1) containing 41 of the 45 individuals sequenced, while two rare haplotypes (H2 and H3) were derived from three individuals and a single individual, respectively. Nucleotide and haplotype diversity were greater overall in the wild populations compared with our managed population. However, C. t. albojubatus was found to exhibit lower nucleotide diversity in both wild and ex situ populations when compared to other wild subspecies. Though the overall goal of the North American wildebeest population is for public education and not reintroduction, maintaining genetic diversity is vital for the long-term viability of this managed population, which may benefit from periodic supplementation of wild animals.


Subject(s)
Antelopes/classification , Antelopes/genetics , Genetic Variation , Animals , Animals, Zoo , DNA, Mitochondrial , Female , Haplotypes , Male , North America , Sequence Analysis, DNA
7.
Mol Biol Rep ; 46(6): 6187-6195, 2019 Dec.
Article in English | MEDLINE | ID: mdl-31486977

ABSTRACT

Indian antelope or Blackbuck (Antilope cervicapra) is one of the widely distributed endemic species in India among wild bovids and a majority of preferred habitats are in human-dominated landscapes. Poaching threats and habitat degradation are major factors for the decline in Blackbuck population from its distribution range. Till date, there is no detailed study using molecular techniques in India on Blackbuck, except a few studies entailing phylogenetic scenario based on inadequate sampling and DNA sequences restricted over limited geographic areas. In view of this, the present study is aimed to screen the Blackbuck samples from a large part of its distribution range and to investigate the genetic diversity as well as to identify the forensically informative nucleotide sequences (FINS) for species identification. We relied on multi-genes approach using three genes of mtDNA genome viz. Cytochrome Oxidase I, Cytochrome b and 16S rRNA and identified the FINS in the Blackbuck population along with conspecific sequences divergence and genetic diversity indices. In all three genes, we observed 8 to 17 haplotypes with the intra-species sequence divergence of 0.004-0.016. Inter-species sequence divergence with the other closely related species of the Blackbuck was 0.0225-0.033. We report the presence of FINS across three genes from 12 to 18 and found more informative nucleotide sites using Cytochrome Oxidase I genes compared to Cytochrome b and 16S rRNA gene. We did not observe the presence of geographic-specific FINS amongst Blackbuck population that can be used to assign individuals to geographic origin. Besides, in the phylogenetic tree, samples from different locations did not cluster into geographic-specific clade and exhibited mixed homology for these sequences. We suggest exploring the feasibility of using nuclear markers for population assignment.


Subject(s)
Antelopes/genetics , Genetic Variation , Genome, Mitochondrial , Genomics , Animals , Antelopes/classification , Base Composition , Evolution, Molecular , Genes, Mitochondrial , Genetics, Population , Genomics/methods , India , Phylogeny
8.
Mol Phylogenet Evol ; 139: 106560, 2019 10.
Article in English | MEDLINE | ID: mdl-31323336

ABSTRACT

Evolutionary relationships between members of the Antilopina taxon have been much debated in recent years. The 'true antelope' clade is currently comprised of 4 genera viz., Gazella, Nanger, Eudorcas and the monotypic genus Antilope, that includes A. cervicapra. Most studies have focused on the mitochondrial genome or morphological data to study their relationships. However, signals from mitochondrial data can often be misleading when compared with nuclear markers, as has been shown in multiple taxonomic groups. In this study, we revisit the phylogenetic relationships among members of Antilopina, particularly the phylogenetic position of A. cervicapra, using 12 nuclear markers and compare it with the mitochondrial tree. Furthermore, we explore the implications of the results of this study on the taxonomy and biogeography of Indian antelopes. The nuclear phylogenetic trees built using multiple coalescent and concatenated methods all supported a paraphyletic genus Gazella. Antilope was nested within Gazella as opposed to being sister to it, which was suggested by previous studies and our results based on mitochondrial markers. Our fossil-calibrated larger bovid phylogeny, based on nuclear markers, suggested that the Antilope lineage diverged from its sister species more recently in the Pleistocene, rather than in late Miocene as per previous studies. Our biogeographic analyses suggest that the lineage leading to genus Antilope dispersed into India from the Saharo-Arabian realm around 2 mya, post the expansion of grasslands. We speculate that the adaptations of this savanna-grassland specialist did not allow them to extend their range beyond the Indian subcontinent. Whereas, the only other true antelope in India, G. bennetti, extended its range into India more recently, probably after the establishment of the Thar desert in northwest India.


Subject(s)
Antelopes/classification , Biological Evolution , Cell Nucleus/genetics , Animals , Antelopes/genetics , Fossils , Mitochondria/genetics , Phylogeny
9.
G3 (Bethesda) ; 9(6): 1785-1793, 2019 06 05.
Article in English | MEDLINE | ID: mdl-31000506

ABSTRACT

Genome-wide assessment of genetic diversity has the potential to increase the ability to understand admixture, inbreeding, kinship and erosion of genetic diversity affecting both captive (ex situ) and wild (in situ) populations of threatened species. The sable antelope (Hippotragus niger), native to the savannah woodlands of sub-Saharan Africa, is a species that is being managed ex situ in both public (zoo) and private (ranch) collections in the United States. Our objective was to develop whole genome sequence resources that will serve as a foundation for characterizing the genetic status of ex situ populations of sable antelope relative to populations in the wild. Here we report the draft genome assembly of a male sable antelope, a member of the subfamily Hippotraginae (Bovidae, Cetartiodactyla, Mammalia). The 2.596 Gb draft genome consists of 136,528 contigs with an N50 of 45.5 Kbp and 16,927 scaffolds with an N50 of 4.59 Mbp. De novo annotation identified 18,828 protein-coding genes and repetitive sequences encompassing 46.97% of the genome. The discovery of single nucleotide variants (SNVs) was assisted by the re-sequencing of seven additional captive and wild individuals, representing two different subspecies, leading to the identification of 1,987,710 bi-allelic SNVs. Assembly of the mitochondrial genomes revealed that each individual was defined by a unique haplotype and these data were used to infer the mitochondrial gene tree relative to other hippotragine species. The sable antelope genome constitutes a valuable resource for assessing genome-wide diversity and evolutionary potential, thereby facilitating long-term conservation of this charismatic species.


Subject(s)
Antelopes/genetics , Genome , Genomics , Whole Genome Sequencing , Animals , Antelopes/classification , Biodiversity , Biological Evolution , Computational Biology/methods , Female , Genetic Variation , Genetics, Population , Genome, Mitochondrial , Genomics/methods , Male , Molecular Sequence Annotation , Phenotype , Phylogeny , United States
10.
J Genet ; 97(5): e101-e109, 2018 Nov 01.
Article in English | MEDLINE | ID: mdl-30574875

ABSTRACT

The bluewildebeest (Connochaetes taurinus) is distributed throughout southern and east Africa while the black wildebeest (Connochaetes gnou) is endemic to South Africa and was driven to near extinction in the early 1900s due to hunting pressure and disease outbreaks. Extensive translocation of both species throughout South Africa is threatening the genetic integrity of blue and blackwilde beest. To effectively manage these species, genetic tools that can be used to detect hybrid individuals, identify genetically unique subpopulations and determine the levels of genetic diversity are required. In this study, 11 microsatellite markers were developed for wildebeest through next-generation sequencing. The microsatellite loci displayed 2.00-4.14 alleles, unbiased heterozygosity values ranged from 0.32 to 0.60 and observed heterozygosity values ranged from 0.26 to 0.52. The comparatively high level of polymorphism observed in the microsatellite markers indicates that these markers can contribute significantly to our knowledge of population genetic structure, relatedness, genetic diversity and hybridization in these species.


Subject(s)
Antelopes/classification , Antelopes/genetics , Genetics, Population , Microsatellite Repeats , Polymorphism, Genetic , Animals , Heterozygote , High-Throughput Nucleotide Sequencing , Species Specificity
11.
Arq. bras. med. vet. zootec. (Online) ; 70(5): 1505-1513, set.-out. 2018. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-947128

ABSTRACT

The aim of this study was to establish normal baseline ERG values of 23 anesthetized deer belonging to 8 neotropical species (Mazama americana, Mazama nemorivaga, Mazama gouazoubira, Mazama nana, Mazama bororo, Ozotocerus bezoarticus, Odocoileus virginianus and Blastocerus dichotomus). Only right eyes were studied. Chemical restraint was performed using xylazine associated with ketamine, IM, for M. americana, M. gouazoubira, M. nemorivaga, M. nana, M. bororo, O. bezoarticus and O. virginianus. A combination of tiletamine/zolazepam diluted in xylazine 2% was used for B. dichotomus individuals. After 20min of dark adaptation, electroretinograms were obtained using a handheld electroretinography (ERG) machine using the QuickRetCheck Protocol at three different light intensities: 0.01cd.s/m2, 3cd.s/m2, and 10cd.s/m2. After light adaptation, photopic phase was recorded. A-wave amplitude recorded during pattern mixed rod/cone response in M. americana was significantly lower when compared to B. dichotomus. No other differences were observed between the species studied. ERG in Neotropical deer is applicable using a portable ERG system and did not show differences among species in relation to the retinal response at different light intensities. Therefore, the lifestyle of the species is more dictated by the selection pressure of the environment than by physiological factors.(AU)


Objetivou-se estabelecer valores de referência para eletrorretinografia (ERG) de 23 cervídeos anestesiados, de oito espécies neotropicais (Mazama americana, Mazama nemorivaga, Mazama gouazoubira, Mazama nana, Mazama bororo, Ozotocerus bezoarticus, Odocoileus virginianus e Blastocerus dichotomus). Somente os olhos direitos foram estudados. A contenção química foi realizada com cetamina/xilazina, IM, nas seguintes espécies: M. americana, M. gouazoubira, M. nemorivaga, M. nana, M. bororo, O. bezoarticus e O. virginianus. Para o B. dichotomus, foi utilizada a associação de tiletamina/zolazepam e xilazina. Após 20 minutos de adaptação ao escuro, os eletrorretinogramas foram obtidos com aparelho portátil de ERG, utilizando-se o protocolo "QuickRet Check", em três intensidades de luz: 0.01cd.s/m2, 3cd.s/m2 e 10cd.s/m2. Após adaptação à luz, realizou-se a fase fotóptica. Os valores para amplitude da onda A durante a resposta padrão mista de cones/bastonetes em M. americana foram significativamente menores quando comparados aos do B. dichotomus. Não foram observadas outras diferenças entre as espécies. A realização de ERG em cervídeos neotropicais é aplicável utilizando-se aparelho portátil e não demonstrou diferenças quanto à resposta retiniana a diferentes intensidades de luz. Dessa forma, o estilo de vida das espécies é ditado mais pela pressão de seleção do ambiente do que por fatores fisiológicos.(AU)


Subject(s)
Animals , Antelopes/classification , Electroretinography/methods , Animals, Wild
12.
BMC Evol Biol ; 17(1): 212, 2017 09 06.
Article in English | MEDLINE | ID: mdl-28877669

ABSTRACT

BACKGROUND: This study aims to assess the role that Pleistocene refugia, rivers and local habitat conditions may have played in the evolutionary diversification of three central African duiker species (Cephalophus dorsalis, C. callipygus and Philantomba monticola). Genetic data from geo-referenced feces were collected from a wide range of sites across Central Africa. Historical patterns of population genetic structure were assessed using a ~ 650 bp fragment of the mitochondrial control region and contemporary patterns of genetic differentiation were evaluated using 12 polymorphic microsatellite loci. RESULTS: Mitochondrial analyses revealed that populations of C. callipygus and P. monticola in the Gulf of Guinea refugium are distinct from other populations in west central Africa. All three species exhibit signatures of past population expansion across much of the study area consistent with a history of postglacial expansion. There was no strong evidence for a riverine barrier effect in any of the three species, suggesting that duikers can readily cross major rivers. Generalized dissimilarity models (GDM) showed that environmental variation explains most of the nuclear genetic differentiation in both C. callipygus and P. monticola. The forest-savanna transition across central Cameroon and the Plateaux Batéké region in southeastern Gabon show the highest environmentally-associated turnover in genetic variability. A pattern of genetic differentiation was also evident between the coast and forest interior that may reflect differences in precipitation and/or vegetation. CONCLUSIONS: Findings from this study highlight the historical impact of Pleistocene fragmentation and current influence of environmental variation on genetic structure in duikers. Conservation efforts should therefore target areas that harbor as much environmentally-associated genetic variation as possible in order to maximize species' capacity to adapt to environmental change.


Subject(s)
Antelopes/classification , Antelopes/genetics , Africa, Central , Animals , Biological Evolution , DNA, Mitochondrial/genetics , Ecosystem , Forests , Genetic Drift , Genetic Speciation , Genetic Variation , Genetics, Population , Phylogeny , Phylogeography , Refugium , Rivers
13.
Mol Phylogenet Evol ; 98: 1-10, 2016 May.
Article in English | MEDLINE | ID: mdl-26826603

ABSTRACT

African bovids are a famous example of a taxonomic group in which the correlated evolution of body size, feeding mode, gregariousness, and social organization in relation to the preferred habitat type has been investigated. A continuum has been described ranging from small-bodied, sedentary, solitary or socially monogamous, forest- or bush-dwelling, browsing species that seek shelter from predation in dense vegetation, to large-bodied, migratory, highly gregarious, grazing taxa inhabiting open savannahs and relying on flight or group-defense behaviors when facing predators. Here, we examined a geographically widespread clade within the Bovidae (the genus Gazella) that shows minimal interspecific variation in body size and asked if we could still uncover correlated changes of key ecological and behavioral traits during repeated transitions from open-land to mountain-dwelling. Our study used a multi-locus phylogeny (based on sequence variation of Cytb and six nuclear intron markers) of all extant members of the genus Gazella to infer evolutionary patterns of key ecological and behavioral traits and to estimate ancestral character states using Bayesian inference. At the base of the Gazella-phylogeny, open plains were inferred as the most likely habitat type, and three independent transitions toward mountain-dwelling were uncovered. Those shifts coincided with shifts from migratory to sedentary lifestyles. Character estimation for group size was largely congruent with movement patterns in that species forming large groups tended to be migratory, while small group size was correlated with a sedentary lifestyle. Evolutionary patterns of two other conspicuous traits (twinning ability vs. exclusive singleton births and hornless vs. horned females) did not follow this trend in the Gazella-phylogeny. Furthermore, we inferred the genus Gazella to have emerged in the Late Miocene to Pliocene (10-3Mya), and estimating ancestral ranges based on a Dispersal-Extinction-Cladogenesis model found the Middle East to be the most likely origin of the genus.


Subject(s)
Antelopes/classification , Antelopes/genetics , Ecosystem , Phylogeny , Animal Migration , Animals , Antelopes/anatomy & histology , Bayes Theorem , Body Size , Evolution, Molecular , Female , Genetic Speciation , Genetic Variation/genetics , Middle East , Phylogeography , Pregnancy , Pregnancy, Multiple
14.
Biol Lett ; 11(11)2015 Nov.
Article in English | MEDLINE | ID: mdl-26582842

ABSTRACT

Hybridization can occur naturally among diverging lineages as part of the evolutionary process leading to complete reproductive isolation, or it can result from range shifts and habitat alteration through global warming and/or other anthropogenic influences. Here we report a molecular cytogenetic investigation of hybridization between taxonomically distinct species of the Alcelaphini (Alcelaphus buselaphus 2n = 40 × Damaliscus lunatus 2n = 36) and the Tragelaphini (Tragelaphus strepsiceros 2n = 31/32 × Tragelaphus angasii 2n = 55/56). Cross-species fluorescence in situ hybridization provides unequivocal evidence of the scale of karyotypic difference distinguishing parental species. The findings suggest that although hybrid meiosis of the former cross would necessitate the formation of a chain of seven, a ring of four and one trivalent, the progeny follow Haldane's rule showing F1 male sterility and female fertility. The tragelaphine F1 hybrid, a male, was similarly sterile and, given the 11 trivalents and chain of five anticipated in its meiosis, not unexpectedly so. We discuss these findings within the context of the broader evolutionary significance of hybridization in African antelope, and reflect on what these hold for our views of antelope species and their conservation.


Subject(s)
Antelopes/genetics , Cytogenetic Analysis , Animals , Antelopes/classification , Biological Evolution , Female , Genetic Speciation , Hybridization, Genetic , In Situ Hybridization, Fluorescence , Infertility, Male/genetics , Karyotyping , Male , Meiosis/genetics , Reproductive Isolation
15.
PLoS One ; 10(3): e0116401, 2015.
Article in English | MEDLINE | ID: mdl-25760948

ABSTRACT

The mountain gazelle (Gazella gazelle), Dorcas gazelle (Gazella Dorcas) and acacia gazelle (Gazella arabica acacia) were historically abundant in the southern Levant, and more specifically in Israel. Anthropogenic and natural changes have caused a rapid decline in gazelle populations, raising concerns about their conservation status and future survival. The genetic profile of 111 wild gazelles from Israel was determined based on three regions of mitochondrial DNA (control region, Cytochrome b and 12S ribosomal RNA) and nine nuclear microsatellite markers. Genetic analysis of the mountain gazelle population, the largest known population of this rare species, revealed adequate diversity levels and gene flow between subpopulations. Nevertheless, ongoing habitat degradation and other human effects, such as poaching, suggest the need for drastic measures to prevent species extinction. Dorcas gazelles in Israel displayed inbreeding within subpopulations while still maintaining considerable genetic diversity overall. This stable population, represented by a distinctive genetic profile, is fragmented and isolated from its relatives in neighboring localities. Based on the genetic profile of a newly sampled subpopulation in Israel, we provide an alternative hypothesis for the historic dispersal of Dorcas gazelle, from the Southern Levant to northern Africa. The small acacia gazelle population was closest to gazelles from the Farasan Islands of Saudi Arabia, based on mitochondrial markers. The two populations did not share haplotypes, suggesting that these two populations may be the last remnant wild gazelles of this species worldwide. Only a dozen acacia gazelles survive in Israel, and urgent steps are needed to ensure the survival of this genetically distinctive lineage. The genetic assessments of our study recognize new conservation priorities for each gazelle species in the Southern Levant.


Subject(s)
Antelopes/classification , Antelopes/genetics , DNA/genetics , Sequence Analysis, DNA/methods , Animals , Cell Nucleus/genetics , Conservation of Natural Resources , Gene Flow , Genetic Variation , Israel , Microsatellite Repeats , Mitochondria/genetics , Molecular Sequence Data , Phylogeny , Phylogeography
16.
Chromosoma ; 124(2): 235-47, 2015 Jun.
Article in English | MEDLINE | ID: mdl-25416455

ABSTRACT

The evolutionary clade comprising Nanger, Eudorcas, Gazella, and Antilope, defined by an X;BTA5 translocation, is noteworthy for the many autosomal Robertsonian fusions that have driven the chromosome number variation from 2n = 30 observed in Antilope cervicapra, to the 2n = 58 in present Eudorcas thomsoni and Eudorcas rufifrons. This work reports the phylogenetic relationships within the Antilopini using comprehensive cytogenetic data from A. cervicapra, Gazella leptoceros, Nanger dama ruficollis, and E. thomsoni together with corrected karyotypic data from an additional nine species previously reported in the literature. Fluorescence in situ hybridization using BAC and microdissected cattle painting probes, in conjunction with differential staining techniques, provide the following: (i) a detailed analysis of the E. thomsoni chromosomes, (ii) the identification and fine-scale analysis the BTA3 orthologue in species of Antilopini, and (iii) the location of the pseudoautosomal regions on sex chromosomes of the four species. Our phylogenetic analysis of the chromosomal data supports monophyly of Nanger and Eudorcas and suggests an affiliation between A. cervicapra and some of the Gazella species. This renders Gazella paraphyletic and emphasizes a closer relationship between Antilope and Gazella than what has previously been considered.


Subject(s)
Antelopes/classification , Antelopes/genetics , Chromosomes, Mammalian/genetics , Animals , Biological Evolution , Cattle , Centromere/genetics , Chromosome Painting , Cloning, Molecular , DNA, Satellite/genetics , Evolution, Molecular , Female , Gene Rearrangement , In Situ Hybridization, Fluorescence , Karyotyping , Male , Phylogeny , Sex Chromosomes/genetics , Translocation, Genetic
18.
Zoo Biol ; 33(5): 440-5, 2014.
Article in English | MEDLINE | ID: mdl-25043251

ABSTRACT

The lesser kudu (Tragelaphus imberbis) is a spiral-horned antelope native to northeastern Africa. Individuals kept in zoological gardens are suspected to be highly inbred due to few founder individuals and a small breeding stock. A morphological study suggested two distinct subspecies of the lesser kudu. However, subspecies designation and population structure in zoological gardens has not been analyzed using molecular markers. We analyzed one mitochondrial marker and two nuclear intron loci (total: 2,239 nucleotides) in 52 lesser kudu individuals. Of these, 48 individuals were bred in captivity and sampled from seven different zoos. The four remaining individuals were recently captured in Somalia and are currently held in the Maktoum zoo. Maternally inherited mitochondrial sequences indicate substantial amounts of genetic variation in the zoo populations, while the biparentally inherited intron sequences are, as expected, less variable. The analyzed individuals show 10 mitochondrial haplotypes with a maximal distance of 10 mutational steps. No prominent subspecies structure is detectable in this study. For further studies of the lesser kudu population genetics, we present microsatellite markers from a low-coverage genome survey using 454 sequencing technology.


Subject(s)
Animals, Zoo/genetics , Antelopes/genetics , Genetic Variation , Genome/genetics , Animals , Antelopes/classification , Base Sequence , DNA Primers/genetics , DNA, Mitochondrial/genetics , Founder Effect , Genetics, Population , Haplotypes/genetics , Microsatellite Repeats/genetics , Molecular Sequence Data , Polymerase Chain Reaction/veterinary , Sequence Alignment , Sequence Analysis, DNA/veterinary , Species Specificity
19.
PLoS One ; 9(6): e98693, 2014.
Article in English | MEDLINE | ID: mdl-24956104

ABSTRACT

Managers of threatened species often face the dilemma of whether to keep populations separate to conserve local adaptations and minimize the risk of outbreeding, or whether to manage populations jointly to reduce loss of genetic diversity and minimise inbreeding. In this study we examine genetic relatedness and diversity in three of the five last remaining wild populations of dama gazelle and a number of captive populations, using mtDNA control region and cytochrome b data. Despite the sampled populations belonging to the three putative subspecies, which are delineated according to phenotypes and geographical location, we find limited evidence for phylogeographical structure within the data and no genetic support for the putative subspecies. In the light of these data we discuss the relevance of inbreeding depression, outbreeding depression, adaptive variation, genetic drift, and phenotypic variation to the conservation of the dama gazelle and make some recommendations for its future conservation management. The genetic data suggest that the best conservation approach is to view the dama gazelle as a single species without subspecific divisions.


Subject(s)
Antelopes/classification , Antelopes/genetics , Conservation of Natural Resources , Endangered Species , Africa , Animals , Cytochromes b/genetics , Evolution, Molecular , Geography , Haplotypes/genetics , Mutation/genetics , Phylogeography , Population Dynamics
20.
PLoS One ; 8(4): e60712, 2013.
Article in English | MEDLINE | ID: mdl-23637761

ABSTRACT

The extent to which a species responds to environmental changes is mediated not only by extrinsic processes such as time and space, but also by species-specific ecology. The Qinghai-Tibetan Plateau uplifted approximately 3000 m and experienced at least four major glaciations during the Pleistocene epoch in the Quaternary Period. Consequently, the area experienced concurrent changes in geomorphological structure and climate. Two species, the Tibetan antelope (Pantholops hodgsonii, chiru) and Tibetan gazelle (Procapra picticaudata), both are endemic on the Qinghai-Tibetan Plateau, where their habitats overlap, but have different migratory behaviors: the chiru is inclined to have female-biased dispersal with a breeding migration during the calving season; in contrast, Tibetan gazelles are year-round residents and never migrate distantly. By using coalescence methods we compared mitochondrial control region DNA sequences and variation at nine microsatellite loci in these two species. Coalescent simulations indicate that the chiru and Tibetan gazelle do not share concordant patterns in their genealogies. The non-migratory Tibetan gazelle, that is more vulnerable to the impact of drastic geographic changes such as the elevation of the plateau, glaciations and so on, appears to have a strong population genetic structure with complicated demographic history. Specifically, the Tibetan gazelle population appears to have experienced isolation and divergence with population fluctuations since the Middle Pleistocene (0.781 Ma). However, it showed continued decline since the Upper Pleistocene (0.126 Ma), which may be attributed to the irreversible impact of increased human activities on the plateau. In contrast, the migratory chiru appears to have simply experienced population expansion. With substantial gene flow among regional populations, this species shows no historical population isolation and divergence. Thus, this study adds to many empirical studies that show historical and contemporary extrinsic and intrinsic processes shape the recent evolutionary history and population genetic structure of species.


Subject(s)
Antelopes/genetics , Behavior, Animal , Environment , Genetics, Population , Animals , Antelopes/classification , DNA, Mitochondrial , Ecosystem , Evolution, Molecular , Female , Gene Flow , Genetic Variation , Genotype , Geography , Male , Microsatellite Repeats , Molecular Sequence Data , Phylogeny , Phylogeography , Population Dynamics , Tibet
SELECTION OF CITATIONS
SEARCH DETAIL
...