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1.
In this study, we aimed to assess the sequence diversity of major histocompatibility complex (MHC) class-II DRB gene at exon 2 in gazelles raised in Sanliurfa Province of Turkey. Twenty DNA samples isolated from gazelles (Gazella subgutturosa) were used for sequencing exon 2 of MHC class-II DRB gene. Target region was amplified by polymerase chain reaction (PCR) and their products were directly sequenced. Nine of these 20 samples yielded unambiguously readable sequences. Three of the nine samples were homozygotes and each showed different sequences. A 262-bp sequence obtained from the three homozygote samples were submitted to GenBank (accession numbers: KC309405, KC309406 and KC309407). Using an allele specific PCR, we detected 10 additional haplotypes. Among 13 haplotypes, 45 nucleotide positions were polymorphic and most of the polymorphic nucleotide positions localized at peptide-binding region (PBR). Rates of nonsynonymous substitutions were significantly higher than synonymous substitutions at PBR. Phylogenetic analysis of the haplotypes showed that 10 haplotypes of the gazelles were clustered together while three were clustered with ovine and bovine haplotypes. The results indicated that at least 13 haplotypes at exon 2 of MHC class-II DRB gene were showing high degree of nucleotide and amino acid diversity, and certain haplotypes of G. subgutturosa were more similar to haplotypes from sheep or cattle than to each other. Rates of synonymous and nonsynonymous substitutions suggested that positive selection was a driving force for diversity at this locus in G. subgutturosa.  相似文献   

2.
Goitered gazelles, Gazella subgutturosa, exist in arid and semiarid regions of Asia from the Middle to the Far East. Although large populations were present over a vast area until recently, a decline of the population as a result of hunting, poaching, and habitat loss led to the IUCN classification of G. subgutturosa as “vulnerable." We examined genetic diversity, structure, and phylogeny of G. subgutturosa using mitochondrial cytochrome b sequences from 18 geographically distant populations in Iran. The median‐joining network of cyt b haplotypes indicated that three clades of goitered gazelles can be distinguished: a Middle Eastern clade west of the Zagros Mountains (and connected to populations in Turkey and Iraq), a Central Iranian clade (with connection to Azerbaijan), and an Asiatic clade in northeastern Iran (with connection to Turkmenistan, Uzbekistan, and other Asian countries as far as northeastern China and Mongolia). Based on our results, we argue that Iran is the center of diversification of goitered gazelles, due to the presence of large mountain ranges and deserts that lead to the separation of populations. In accordance with previous morphological studies, we identified the Asiatic clade as the subspecies G. s. yarkandensis, and the other two clades as the nominate form G. s. subgutturosa. The new genetic information for goitered gazelles in Iran provides the basis for future national conservation programs of this species.  相似文献   

3.
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.  相似文献   

4.
The Goitered Gazelle, Gazella subgutturosa, is the most widespread gazelle species in the Middle East and central Asia inhabiting desert and semi-desert habitats. Today it is threatened and its geographic range and population size have experienced significant decline in the last decades. In Iran, the remnant populations are confined to fragmented habitats. We aimed to characterise genetic diversity and phylogenetic status of the populations of Goitered Gazelle in Central Iran and to evaluate the potential effect of a historic population bottleneck on the genetic variation of today’s population. We used noninvasive sampling to uncover structure and level of genetic variation in a fragment of the cytochrome-b gene from 170 samples. Genealogical analyses were performed using HKY+I model and phylogenetic trees reconstructed using Bayesian inference and maximum likelihood. We found extremely low levels of genetic variation, with altogether only five haplotypes in samples from different populations. Overall haplotype diversity was 0.081 and nucleotide diversity 0.0003. The mean observed mismatch between any two sequences was 0.093 with the largest peak for small numbers. The mismatch distribution fit the model of population expansion and suggested that gazelles had experienced a sudden expansion. An unrooted median-joining network analysis of mtDNA haplotypes showed a star-like structure which few mutations steps separating the haplotypes from other regions. Our findings strengthen the urgency of preserving the species’ genetic diversity to prevent local extinction.  相似文献   

5.
Ants are among the most important elements in many ecosystems and known as famous ecosystem engineers. By changing physical and chemical properties of soil, ants may provide suitable habitats for other species. Based on previous observations, we hypothesized that Persian goitered gazelles (Gazella subgutturosa subgutturosa) exhibit a preference for utilizing sites close to seed harvester ant (Messor spp.) nests. We tested our hypothesis by (1) mapping the occurrence of harvester ant nests and aggregated gazelle pellet groups along 31 strip transects, (2) monitoring pellet group accumulation bimonthly at 56 pairs of permanent plots established on ant nests and at adjacent control sites for a complete year, and (3) comparing vegetation and soil parameters between ant nest sites used by gazelles and paired control plots without ant nests. Although the area of Messor spp. nest sites covered only about 0.29% of the sampled transects, 84% of the gazelle pellet group aggregation sites were positioned upon ant nests, suggesting that gazelles actively selected Messor spp. nest sites. Pair-wise comparisons between ant nest plots and paired control plots also confirmed higher use of ant nest sites by gazelles compared to sites without ant nests in all time periods. Percent soil organic matter, percent cover of gravel, and annual herb vegetation significantly differed between ant nest and paired control plots in all the vegetation communities. We suggest that the alterations brought about by harvester ants on soil and vegetation make these sites attractive to gazelles. Gazelle territoriality behaviour and use of ant nests as bedding sites may be the reasons for selection of ant nest sites by gazelles.  相似文献   

6.
Polymorphism of the nucleotide sequence of a hypervariable fragment of the D-loop (985 bp) of mtDNA in 76 Goitered gazelles of subspecies Gazella subgutturosa subgutturosa from Uzbekistan, Turkmenistan, and Azerbaijan was studied. The genetic similarity of gazelles from Turkmenistan and Uzbekistan has been identified. The population of gazelles from Shirvanskaya steppe reserve (Azerbaijan) is unique and strictly isolated from other groups studied. A high haplotypic (H = 0.9649 ± 0.0091) and relatively low nucleotide diversity (π = 0.0212 ± 0.0105) were noted for all investigated groups of gazelle based on this mtDNA fragment, which is probably related to ecological peculiarities of the species and the history of formation of regional populations.  相似文献   

7.
The goitered gazelle, Gazella subgutturosa, is a medium-sized ungulate inhabiting arid and semi-arid regions in the Middle East and central Asia. The intraspecific classification of the species remains unclear. We analysed the genetic diversity in mitochondrial DNA control region (CR) sequences (976?bp) from 104 wild samples from the Xinjiang Uyghur Autonomous Region (XUAR) in north-west China, and reconstructed phylogeny with additional sequences from across the species’ range. We detected 58 haplotypes in XUAR populations, all but three of which were specific to single sampling sites. The phylogenetic analysis displayed two obvious clades of mtDNA haplotypes and the other haplotypes differed from the two clades. A median-joining network showed three groups of haplotypes were to a high extent concordant with the phylogenetic tree. The haplotype clustering was consistent with their geographic distribution. Nei’s net sequence divergences amongst the three groups ranged from 0.010 to 0.018 and indicated three subspecies, two of which inhabit XUAR. We detected strong differentiation between northern (NX) and southern (SX) XUAR populations overall (FST?=?0.4448, P?相似文献   

8.
明确物种生境空间分布格局及其与环境因素的关系,对了解该物种的生境需求和适宜生境空间分布至关重要。生境评价和预测是对物种进行有效保护的基础。以鹅喉羚(Gazella subgutturosa)为研究对象,以其重要栖息地新疆博州艾比湖国家级湿地自然保护区为研究区域,选取115个鹅喉羚分布点数据和23个环境变量因子,应用MAXENT模型分析其生境空间分布及主要影响因子,划分了鹅喉羚在研究区域的适宜生境,并对它的栖息地特征进行了分析。探讨了鹅猴羚生境选择与环境因子的关系。结果表明:气温日较差是影响鹅喉羚生境分布的主要环境因子。植被类型,坡度和最干月降水量对艾比湖鹅喉羚的生境选择影响不大。除了温度和降水在内的19项生物气候变量是鹅猴羚选择生境的重要因素之外,海拔和坡向等地形特征也影响鹅猴羚的生境选择性。鹅喉羚的高度适宜生境区主要分布在研究区域的北部和东部,中度及低度适宜生境区则分布于高度适宜生境区的边缘,而非适宜生境区主要集中在西部地区。研究不仅提供了鹅喉羚在艾比湖的实际分布状况及其栖息地特征,也为鹅喉羚在栖息地方面的研究,即鹅猴羚的栖息地选择和环境因子的关系方面提供了一个重要的依据。  相似文献   

9.
A multivariate analysis using canonical variates and the D2 test show that five taxa of Palaearctic gazelles examined are distinct. Several forms of gazelles of dubious taxonomic position were also compared on the canonical axes, with conclusions not dissimilar to those of recent workers on the Arabian gazelles, viz. that there are three distinct species in the Arabian peninsula; Gazella dorcas saudiya, Gazella gazella arabica and Gazella subgutturosa marica. Gazella dorcas populations in Somalia have a local form in G. dorcas pelzelni distinct in horns but not in skull measurements from Gazella spekei in the nearby highlands.  相似文献   

10.
Food preferences of the sand gazelle (Gazella marica) from the Mahazat as-Sayd Protected Area in Saudi Arabia were evaluated using focal animal sampling in conjunction with an eco-morphological method examining two parameters of tooth wear, i.e., occlusal relief and cusp shape. Observations of live, free-ranging animals (n = 53) showed that sand gazelles generally consumed more grass (58.4%) than browse (41.6%). However, during the dry season, gazelles spent significantly more time browsing (51.0%) and less time grazing (49.0%) than under wet conditions (browsing: 17.6%; grazing: 82.4%). Thus, consistent with predictions, sand gazelles are intermediate feeders but shift towards browsing when grass is scarce. The mesowear signature of the sand gazelle is consistent with a grazing signal in other ruminants. In other words, the browse component of the diets of live animals was not reflected in the tooth wear. This could have occurred because browse is less abrasive than grass, but more likely because all food types are heavily abrasive in this dusty habitat. We conclude that the sand gazelle population in Mahazat as-Sayd encounters a highly abrasive diet, which has implications for their ability to meet nutritional demands.  相似文献   

11.
Based on the distinctiveness of their mitochondrial haplotypes and other biological features, several recent publications have proposed that some Echinococcus granulosus strains should be regarded as separate species. However, the genetic cohesion of these species has not been extensively evaluated using nuclear markers. We assess the degree of polymorphism of the partial mitochondrial cox1 (366 bp), the nuclear mdh (214 bp) and EgAgB4 (281-283 bp) genes of E. granulosus sensu lato isolates collected from areas where different strains occur sympatrically. Five distinct mitochondrial haplotypes were determined by direct sequencing (G1, G2, G5, G6 and G7). The mdh genotypes were first screened by SSCP: three alleles were identified (Md1-Md3), which were further confirmed by nucleotide sequencing. For EgAgB4, which was analysed by direct sequencing the PCR products, two groups of sequences were found: EgAgB4-1 and EgAgB4-2. No haplotype-specific mdh or EgAgB4 sequences occur. Nevertheless, alleles Md1 and Md2 and type 1 sequences of EgAgB4 showed a higher frequency within the group of haplotypes G1-G2, while allele Md3 and EgAgB4-2 are most frequent in the G5-G7 cluster. By AMOVA it is shown that 79% of the total genetic variability is found among haplotype groups. These findings are compatible with two not mutually exclusive evolutionary hypotheses: (a) that haplotypes share an ancestral polymorphism, or (b) that the reproductive isolation between parasites with distinct haplotypes is not complete, leading to gene introgression. The biologic and epidemiologic consequences of our findings are discussed.  相似文献   

12.
Gazella is one of the most species‐rich genera within horned ruminants. Despite overall similarity in body size and morphology, gazelles show variability in coloration and horn morphology. Unfortunately, however, species differentiation based on these characters, or on discrete skull characters, is very difficult due to high intraspecific variability. Furthermore, most species have fragmented and allopatric distributions, so that species boundaries were hard to define in the past. Mitochondrial DNA sequences have proven useful for investigating gazelle taxonomy in recent years, but especially for old museum material, i.e. type specimens, destructive sampling is often impossible. We provide a comprehensive morphometric framework for the genus Gazella based on linear skull measurements reconciled with results from molecular phylogenetic analysis based on the largest dataset available so far. In particular for males, the skull morphology shows interspecific differences concurrent with DNA data and provides a reliable tool for species identification. Based on morphometric data we synonymize G. karamii with G. marica, and confirm the identification of the G. arabica and G. a. rueppelli type skulls from analyses of mitochondrial DNA sequences. © 2013 The Linnean Society of London  相似文献   

13.

Background

Mitochondrial introgression may result in the mitochondrial genome of one species being replaced by that of another species without leaving any trace of past hybridization in its nuclear genome. Such introgression can confuse the species genealogy estimates and lead to absurd inferences of species history. We used a phylogenetic approach to explore the potential mitochondrial genome introgression event(s) between two closely related green pond frog species, Pelophylax nigromaculatus and P. plancyi.

Results

DNA sequence data of one mitochondrial and two nuclear genes from an extensive sampling of the two species were collected, and the genealogies of the three genes were constructed and compared. While the two nuclear genes congruently showed mutual reciprocal monophyly of both species, the mitochondrial phylogeny separated a Korean P. nigromaculatus clade, a paraphyletic central China P. plancyi assemblage, and a large well-supported introgression clade. Within the introgression clade, the mitochondrial haplotypes of the two species were mixed together. This reticulated pattern can be most parsimoniously explained by an ancient mitochondrial introgression event from P. plancyi to P. nigromaculatus that occurred at least 1.36 MYA, followed by multiple recent introgression events from P. nigromaculatus back to P. plancyi within the last 0.63 MY. The re-constitution of previously co-adapted genomes in P. plancyi may be responsible for the recent rampant introgression events. The Korean P. nigromaculatus clade likely represents the only surviving "true" mitochondrial lineage of P. nigromaculatus, and the central China P. plancyi assemblage likely represents the "original" P. plancyi mitochondrial lineage. Refugia in the Korean Peninsula and central China may have played a significant role in preserving these ancient lineages.

Conclusions

The majority of individuals in the two species have either introgressed (P. nigromaculatus) or reclaimed (P. plancyi) mitochondrial genomes while no trace of past hybridization in their nuclear genomes was detected. Asymmetrical reproductive ability of hybrids and continuous backcrossing are likely responsible for the observed mitochondrial introgression. This case is unique in that it includes an ancient "forward" introgression and many recent "backward" introgressions, which re-constitutes the original nuclear and mitochondrial genomes of P. plancyi. This hybrid system provides an excellent opportunity to study cyto-nuclear interaction and co-adaptation.  相似文献   

14.
Despite the presence of reproductive barriers between species, interspecific gene introgression has been documented in a range of natural systems. Comparing patterns of genetic introgression in biparental versus matrilineal markers can potentially reveal sex‐specific barriers to interspecific gene flow. Hybridization has been documented in the freshwater turtles Graptemys geographica and G. pseudogeographica, whose ranges are largely sympatric. Morphological differentiation between the species is restricted to females, with female G. geographica possessing large heads and jaws compared to the narrow heads of G. pseudogeographica females. If hybrid females are morphologically intermediate, they may be less successful at exploiting parental feeding niches, thereby limiting the introgression of maternally inherited, but not biparental, molecular markers. We paired sequence data with stable isotope analysis and examined sex‐specific genetic introgression and trophic differentiation in sympatric populations of G. geographica and G. pseudogeographica. We observed introgression from G. pseudogeographica into G. geographica at three nuclear loci, but not at the mitochondrial locus. Analysis of ?15N and ?13C was consistent with species differences in trophic positioning in females, but not males. These results suggest that ecological divergence in females may reduce the opportunity for gene flow in this system.  相似文献   

15.
Bahia state hosts over 90% of hawksbill (Eretmochelys imbricata) nests registered in the main nesting sites monitored by Projeto Tamar-IBAMA in Brazil. The genetic diversity of this hawksbill population (n=119) was assayed through the analyses of 752 bp of the mitochondrial DNA control region in nesting females. Seven distinct haplotypes, defined by 125 polymorphic sites, were found. Most of the individuals (n=67) display four typical hawksbill haplotypes, 50 individuals display two haplotypes characteristic of the loggerhead turtle (Caretta caretta) and two individuals had a haplotype affiliated with the olive ridley (Lepidochelys olivacea). These results demonstrate hybridization between the hawksbills and two species that nest along the Bahia coast. Of special interest is the high occurrence of loggerhead × hawksbill hybrids (42%), which display loggerhead mtDNA haplotypes but are characterized morphologically as hawksbills. The true hawksbill haplotypes present only three variable sites and low genetic diversity values (h=0.358±0.069; π=0.0005±0.0001). The occurrence of several nesting individuals with identical mtDNA from another species may also suggest a long history of introgression between species producing likely F2 or further generation hybrids. Marine turtle hybrids have been previously reported, but the high frequency observed in Bahia is unprecedented. Such introgression may influence evolutionary pathways for all three species, or may introduce novel morphotypes that develop apart from the parental species. The presence of a unique hybrid swarm has profound conservation implications and will significantly influence the development and implementation of appropriate management strategies for these species.  相似文献   

16.
Visual species identification of cetacean strandings is difficult, especially when dead specimens are degraded and/or species are morphologically similar. The two recognised pilot whale species (Globicephala melas and Globicephala macrorhynchus) are sympatric in the North Atlantic Ocean. These species are very similar in external appearance and their morphometric characteristics partially overlap; thus visual identification is not always reliable. Genetic species identification ensures correct identification of specimens. Here we have employed one mitochondrial (D-Loop region) and eight nuclear loci (microsatellites) as genetic markers to identify six stranded pilot whales found in Galicia (Northwest Spain), one of them of ambiguous phenotype. DNA analyses yielded positive amplification of all loci and enabled species identification. Nuclear microsatellite DNA genotypes revealed mixed ancestry for one individual, identified as a post-F1 interspecific hybrid employing two different Bayesian methods. From the mitochondrial sequence the maternal species was Globicephala melas. This is the first hybrid documented between Globicephala melas and G. macrorhynchus, and the first post-F1 hybrid genetically identified between cetaceans, revealing interspecific genetic introgression in marine mammals. We propose to add nuclear loci to genetic databases for cetacean species identification in order to detect hybrid individuals.  相似文献   

17.
18.
Indigenous Chinese goat mtDNA is highly diverse but lacks geographic specificity; however, whether gene flow or gene exchange contributed to this remains unknown. We reanalyzed a consensus fragment of 481 bp in the D-loop region from 339 individuals. The network and neighbor-joining tree revealed three divergent maternal haplogroups (A, B1, and B2) in 17 local breeds. Although high polymorphism resulting in 198 different haplotypes was observed (h = 0.984 ± 0.002; π = 0.0336 ± 0.0008), neither the distribution of haplotypes nor PCA analysis revealed any obvious geographic structure in the local breeds. Extensive gene flow was widely detected among breeds from southwest China. High levels of gene exchange were detected between Qianbei Brown goats and the other breeds, indicating either more contribution or introgression to their gene pools. This study will be helpful in understanding the phylogeography and gene flow among the goat breeds of southwest China.  相似文献   

19.
《Biological Control》2013,64(3):359-369
Hybridization between introduced biological control agents and native species has the potential to impact native biodiversity and pest control efforts. This study reports progress towards predicting the outcome of hybridization between two beetle species, the introduced Laricobius nigrinus Fender and the native L. rubidus LeConte. L. nigrinus is a predator from western North America introduced to hemlock stands in the eastern United States as a biological control of the hemlock woolly adelgid [Adelges tsugae Annand (Hemiptera: Adelgidae)]. Laricobius rubidus is a closely related eastern species that also feeds on A. tsugae but prefers pine adelgids (Pineus strobi Hartig) on white pine (Pinus strobus L.). Six microsatellite markers plus mitochondrial COI haplotypes were used to examine genetic structure of these two Laricobius species across North America. In their native ranges, major geographic features have impacted gene flow: the intermountain region in the West, and the Appalachian Mountains in the East. Analysis of 1229 individuals from adelgid-infested hemlock trees in release sites in the eastern United States found widespread hybridization with asymmetrical introgression towards L. nigrinus on hemlock. The ultimate outcome of hybridization could therefore be a complex mosaic of genetic introgression across the landscape, depending on the distribution of hemlock and pine. This study confirms the importance of evaluating the potential for introduced biological control agents to hybridize with their native relatives. This system also provides an excellent opportunity to improve our understanding of emerging hybrid zones by tracking its progress over time.  相似文献   

20.
Like many other gazelles, goitred gazelles (Gazella subgutturosa) are capable of calling either through the nose or through the open mouth. In particular, juvenile goitred gazelles provide a convenient model for contrasting acoustic characteristics of nasal and oral calls, and for estimating their communicative functions. In this study, acoustic variables (formants, fundamental frequency, duration and power quartiles) of 480 oral and 483 nasal calls, recorded from 20 (9 male, 11 female) individually identified captive juvenile goitred gazelles, were examined for their potential to encode sex and identity of the caller. Discriminant function analysis revealed an equally high potential of oral and nasal calls to encode sex, whereas encoding the individual identity was significantly more accurate for oral calls. Sex was encoded exclusively in formants, whilst individual identity was encoded in a combination of all investigated variables. No correlation was found between body mass and values of any acoustic variable. Analyses controlling for age and sex revealed higher average values for all investigated variables of oral calls compared to nasal calls. We discuss the results in relation to the source‐filter theory, mother–offspring communication and production mechanisms of nasal and oral calls in mammals.  相似文献   

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