首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 203 毫秒
1.
The existence of the Hucul horse on Romanian territory has been documented from the very distant past; today Hucul is a unique breed that is part of the FAO Program for the Preservation of Animal Genetic Resources. We compared Hucul with several primitive European and Asiatic breeds in order to elucidate the origin of these horses. We analyzed a 683-bp mitochondrial DNA (mtDNA) D-loop fragment in a population of Hucul horses and compared the polymorphic sites with sequences from other primitive breeds, including Exmoor, Icelandic Pony, Sorraia, Przewalski Horse, Mongolian Wild Horse, Konik, and Shetland Pony, as well as with Arabian, Akhal Teke and Caspian Pony. The sequences were truncated to 247 bp to accommodate short sequence data for the other species. Eighty horses were analyzed; 35 polymorphic sites representing 33 haplotypes were observed. The mean percentage of polymorphic sites was 14.2% for this mtDNA fragment. A neighbor-joining phylogenetic tree was constructed based on Kimura two-parameter distances and the Network 3.111 software was used for phylogenetic analysis. The Hucul horse was classified separately from all other primitive breeds. It is possible that the Hucul horse is not part of the pony class, as it segregated apart from all primitive pony breeds. We found multiple origins in the maternal lineage of domestic horse breeds and demonstrated the uniqueness of the Hucul breed; its origins remain unclear.  相似文献   

2.
Movements of human populations leave their traces in the genetic makeup of the areas affected; the same applies to the horses that move with their owners This study is concerned with the mitochondrial control region genotypes of 31 archaeological horse remains, excavated from pre-conquest Avar and post-conquest Hungarian burial sites in the Carpathian Basin dating from the sixth to the tenth century. To investigate relationships to other ancient and recent breeds, modern Hucul and Akhal Teke samples were also collected, and mtDNA control region (CR) sequences from 76 breeds representing 921 individual specimens were combined with our sequence data. Phylogenetic relationships among horse mtDNA CR haplotypes were estimated using both genetic distance and the non-dichotomous network method. Both methods indicated a separation between horses of the Avars and the Hungarians. Our results show that the ethnic changes induced by the Hungarian Conquest were accompanied by a corresponding change in the stables of the Carpathian Basin.  相似文献   

3.
Yue XP  Qin F  Campana MG  Liu DH  Mao CC  Wang XB  Lan XY  Chen H  Lei CZ 《Animal genetics》2012,43(5):624-626
Previous mitochondrial DNA (mtDNA) D‐loop and microsatellite studies have shown that Chinese horses have multiple maternal origins and high genetic diversity. To better characterize maternal genetic origins and diversity of Chinese domestic horses, we conducted a comprehensive analysis of 407 complete 1140 bp sequences of the horse mitochondrially encoded cytochrome b (CYTB) gene, including 323 horses from 13 Chinese indigenous breeds and 84 reference sequences from GenBank. A total of 114 haplotypes were identified, of which 73 appeared among the 13 Chinese horse breeds. The high mitochondrially encoded cytochrome b haplotypic diversity suggests multiple maternal origins in Chinese horses.  相似文献   

4.
Although only a few specific pigmentation types are allowed within the Hucul horse registry, accurate determination of particular coat colors can be uncertain due to the presence of variation in color shades and segregation of multiple dun dilution variants. Herein, we genotyped the previously identified polymorphisms within two coat color loci TBX3 (T-box 3) and ASIP (Agouti Signaling Protein) in 462 Hucul individuals and compared the genotype predicted phenotypes with observed pigmentation types provided in the Polish Horse Breeders Association database. We identified disagreement between the predicted and recorded coat color in 157 horses (34%). The most common error was misclassification of horses with the nd1/nd1 and nd1/nd2 genotypes, what may be related with the occurrence of some ‘intermediate’ dilution phenotypes in such individuals. We have also proven that the frequency of the dominant dun dilution allele (D) (0.30) is higher than previously predicted by available studbooks. The D allele(s) is easily ‘hidden’ in various phenotypic groups including dark bay and black, therefore we hypothesized that the dun dilution effect itself is not as strongly epistatic in the Hucul horse as described in other horse breeds. This may be the result of an additional genetic modifier suppressing D allele phenotypic effect.  相似文献   

5.
The maternal and paternal genetic variation of horse breeds from the Baltic Sea region, including three local Estonian breeds, was assessed and compared with that of Altai and Yakutian horses. In the mtDNA D‐loop region, 72 haplotypes assigned to 20 haplogroups in the nine breeds were detected. In Estonian local breeds, 38 mtDNA haplotypes were found, and five of them were shared by the three breeds. More than 60% of all identified haplotypes were rare. Compared with the Estonian Native and Estonian Heavy Draught breeds, a higher haplotypic diversity was found in the Tori breed (h = 0.969). Moreover, four haplotypes shared among Finnish and Estonian local horse breeds indicated ancient ancestry, and of these, H30 (haplogroup D3) showed global sharing and genetic links between modern Baltic Sea region and Siberian horses, specifically. The studied breed set showed high variability in maternal inheritance and mixed patterns of the international and native breeds of the Siberian and Baltic regions. No variation was found in paternally inherited markers among horse breeds in the Baltic Sea region.  相似文献   

6.
The paternally inherited Y chromosome displays the population genetic history of males. While modern domestic horses (Equus caballus) exhibit abundant diversity within maternally inherited mitochondrial DNA, no significant Y-chromosomal sequence diversity has been detected. We used high throughput sequencing technology to identify the first polymorphic Y-chromosomal markers useful for tracing paternal lines. The nucleotide variability of the modern horse Y chromosome is extremely low, resulting in six haplotypes (HT), all clearly distinct from the Przewalski horse (E. przewalskii). The most widespread HT1 is ancestral and the other five haplotypes apparently arose on the background of HT1 by mutation or gene conversion after domestication. Two haplotypes (HT2 and HT3) are widely distributed at high frequencies among modern European horse breeds. Using pedigree information, we trace the distribution of Y-haplotype diversity to particular founders. The mutation leading to HT3 occurred in the germline of the famous English Thoroughbred stallion “Eclipse” or his son or grandson and its prevalence demonstrates the influence of this popular paternal line on modern sport horse breeds. The pervasive introgression of Thoroughbred stallions during the last 200 years to refine autochthonous breeds has strongly affected the distribution of Y-chromosomal variation in modern horse breeds and has led to the replacement of autochthonous Y chromosomes. Only a few northern European breeds bear unique variants at high frequencies or fixed within but not shared among breeds. Our Y-chromosomal data complement the well established mtDNA lineages and document the male side of the genetic history of modern horse breeds and breeding practices.  相似文献   

7.
The maintenance of genetic diversity is one of the chief concerns in the captive breeding of endangered species. Using microsatellite and mtDNA markers, we examined the effects of two key variables (parental number and duration of breeding period) on effective population size (Ne) and genetic diversity of offspring in an experimental breeding program for the endangered Tokyo bitterling, Tanakia tanago. Average heterozygosity and number of alleles of offspring estimated from microsatellite data increased with parental number in a breeding aquarium, and exhibited higher values for a long breeding period treatment (9 weeks) compared with a short breeding period (3 weeks). Haplotype diversity in mtDNA of offspring decreased with the reduction in parental number, and this tendency was greater for the short breeding period treatment. Genetic estimates of Ne obtained with two single‐sample estimation methods were consistently higher for the long breeding period treatment with the same number of parental fish. Average Ne/N ratios were ranged from 0.5 to 1.4, and were high especially in the long breeding period with small and medium parental number treatments. Our results suggest that the spawning intervals of females and alternative mating behaviors of males influence the effective size and genetic diversity of offspring in bitterling. To maintain the genetic diversity of captive T. tanago, we recommend that captive breeding programs should be conducted for a sufficiently long period with an optimal level of parental density, as well as using an adequate number of parents. Zoo Biol 31:656‐668, 2012. © 2011 Wiley Periodicals, Inc.  相似文献   

8.
To assess the genetic diversity of Japanese native horse populations, we examined seven such populations using mitochondrial DNA (mtDNA) and microsatellite analyses. Four reference populations of Mongolian horses and European breeds were employed as other equids. In the mtDNA analysis, the control region (D-loop) of 411 bp was sequenced, and 12 haplotypes with 33 variable sites were identified in the Japanese native horses. The phylogenetic tree constructed by haplogrouping and using worldwide geographic references indicated that the haplotypes of the Japanese native horses were derived from six equid clusters. Compared with the foreign populations, the Japanese native populations showed lower within-population diversity and higher between-population differentiation. Microsatellite analysis, using 27 markers, found an average number of alleles per locus of 9.6 in 318 native and foreign horses. In most native populations, the within-population diversity was lower than that observed in foreign populations. The genetic distance matrix based on allelic frequency indicated that several native populations had notably high between-population differentiation. The molecular coancestry-based genetic distance matrix revealed that the European populations were differentiated from the Japanese and Mongolian populations, and no clear groups could be identified among the Japanese native horse populations. The genetic distance matrices had few correlations with the geographic distribution of the Japanese native populations. Based on the results of both mtDNA and microsatellite analyses, it could be speculated that each native population was formed by the founder populations derived from Mongolian horses. The genetic construction of each population appears to have been derived from independent breeding in each local area since the time of population fission, and this was accompanied by drastic genetic drift in recent times. This information will help to elucidate the ancestry of Japanese native horses. An erratum to this article can be found at  相似文献   

9.
To obtain more knowledge of the origin and genetic diversity of domestic horses in China, this study provides a comprehensive analysis of mitochondrial DNA (mtDNA) D-loop sequence diversity from nine horse breeds in China in conjunction with ancient DNA data and evidence from archaeological and historical records. A 247-bp mitochondrial D-loop sequence from 182 modern samples revealed a total of 70 haplotypes with a high level of genetic diversity. Seven major mtDNA haplogroups (A–G) and 16 clusters were identified for the 182 Chinese modern horses. In the present study, nine 247-bp mitochondrial D-loop sequences of ancient remains of Bronze Age horse from the Chifeng region of Inner Mongolia in China ( c. 4000–2000a bp ) were used to explore the origin and diversity of Chinese modern horses and the phylogenetic relationship between ancient and modern horses. The nine ancient horses carried seven haplotypes with rich genetic diversity, which were clustered together with modern individuals among haplogroups A, E and F. Modern domestic horse and ancient horse data support the multiple origins of domestic horses in China. This study supports the argument that multiple successful events of horse domestication, including separate introductions of wild mares into the domestic herds, may have occurred in antiquity, and that China cannot be excluded from these events. Indeed, the association of Far Eastern mtDNA types to haplogroup F was highly significant using Fisher's exact test of independence ( P  = 0.00002), lending support for Chinese domestication of this haplogroup. High diversity and all seven mtDNA haplogroups (A–G) with 16 clusters also suggest that further work is necessary to shed more light on horse domestication in China.  相似文献   

10.
To understand the origin and genetic diversity of Iranian native horses, mitochondrial DNA (mtDNA) D‐loop sequences were generated for 95 horses from five breeds sampled in eight geographical locations in Iran. Sequence analysis of a 247‐bp segment revealed a total of 27 haplotypes with 38 polymorphic sites. Twelve of 19 mtDNA haplogroups were identified in the samples. The most common haplotypes were found within haplogroup X2. Within‐population haplotype and nucleotide diversities of the five breeds ranged from 0.838 ± 0.056 to 0.974 ± 0.022 and 0.011 ± 0.002 to 0.021 ± 0.001 respectively, indicating a relatively high genetic diversity in Iranian horses. The identification of several ancient sequences common between the breeds suggests that the lineage of the majority of Iranian horse breeds is old and obviously originated from a vast number of mares. We found in all native Iranian horse breeds lineages of the haplogroups D and K, which is concordant with the previous findings of Asian origins of these haplogroups. The presence of haplotypes E and K in our study also is consistent with a geographical west–east direction of increasing frequency of these haplotypes and a genetic fusion in Iranian horse breeds.  相似文献   

11.
We analysed 123 white‐tailed sea eagles (Haliaeetus albicilla) from (primarily central) Europe with respect to variability and differentiation based on 499 bp of the mitochondrial control region and genotypes at seven unlinked nuclear microsatellites. Variability was high (overall expected heterozygosity, haplotype and nucleotide diversity being 0.70, 0.764 and 0.00698, respectively) and both marker systems showed a subdivision into two main genetic clusters (microsatellites) or haplogroups (mtDNA). In line with earlier analyses focusing on populations from northern and eastern Europe, as well as from Asia, we found a high level of admixture in Europe and no signs of a bottleneck – despite a severe decline of white‐tailed sea eagle populations during the 20th century. Europe is thus a global stronghold for this species not only with respect to the number of breeding pairs but also regarding the proportion of species‐wide genetic diversity. Our dense sampling revealed a possibly clinal variation within central Europe from north‐west to south‐east that was reflected by the distribution of mtDNA haplotypes as well as the two microsatellite‐based clusters. This population differentiation in central Europe probably originated from a geographically structured postglacial colonization and was later enhanced by recent demographic fluctuations. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 99 , 727–737.  相似文献   

12.
Manipuri pony is the geographically distant breed of horse from the five recognized horse breeds found in the Indian subcontinent. The phylogenetic relationship of Manipuri pony with the other breeds is unknown. The diversity in the mitochondrial (mt) DNA D-loop region is employed as an important tool to understand the origin and genetic diversification of domestic horses and to examine genetic relationships among breeds around the world. This study was carried out to understand the maternal lineages of Manipuri pony using the 247 bp region of the mtDNA D-loop. The dataset comprised of eleven numbers of self developed sequences of Manipuri pony, 59 and 35 number of retrieved sequences of Indian horse breeds and other worldwide breeds respectively. A total of 35 haplotypes was identified with a high level of genetic diversity in the Indian breeds. A total of seven major mtDNA haplogroups (A–G) was identified in the Indian horse breeds that indicated the abundance of mtDNA diversity and multiple origins of maternal lineages in them. The majority of the studied sequences of Indian breeds (33.3 %) were grouped into haplogroup D and least (3.9 %) in haplogroup E. The Manipuri breed showed the least FST distance (0.03866) with the most diverged Indian breeds and with Thoroughbred horse among the worldwide. This study indicated a close association between Manipuri pony and Thoroughbred.  相似文献   

13.
The population structure of variation in a nuclear actin intron and the control region of mitochondrial DNA is described for humpback whales from eight regions in the North Pacific Ocean: central California, Baja Peninsula, nearshore Mexico (Bahia Banderas), offshore Mexico (Socorro Island), southeastern Alaska, central Alaska (Prince Williams Sound), Hawaii and Japan (Ogasawara Islands). Primary mtDNA haplotypes and intron alleles were identified using selected restriction fragment length polymorphisms of target sequences amplified by the polymerase chain reaction (PCR–RFLP). There was little evidence of heterogeneity in the frequencies of mtDNA haplotypes or actin intron alleles due to the year or sex composition of the sample. However, frequencies of four mtDNA haplotypes showed marked regional differences in their distributions (ΦST = 0.277; P < 0.001; n = 205 individuals) while the two alleles showed significant, but less marked, regional differences (ΦST = 0.033; P < 0.013; n = 400 chromosomes). An hierarchical analysis of variance in frequencies of haplotypes and alleles supported the grouping of six regions into a central and eastern stock with further partitioning of variance among regions within stocks for haplotypes but not for alleles. Based on available genetic and demographic evidence, the southeastern Alaska and central California feeding grounds were selected for additional analyses of nuclear differentiation using allelic variation at four microsatellite loci. All four loci showed significant differences in allele frequencies (overall FST = 0.043; P < 0.001; average n = 139 chromosomes per locus), indicating at least partial reproductive isolation between the two regions as well as the segregation of mtDNA lineages. Although the two feeding grounds were not panmictic for nuclear or mitochondrial loci, estimates of long-term migration rates suggested that male-mediated gene flow was several-fold greater than female gene flow. These results include and extend the range and sample size of previously published work, providing additional evidence for the significance of genetic management units within oceanic populations of humpback whales.  相似文献   

14.
Domestic horses represent a genetic paradox: although they have the greatest number of maternal lineages (mtDNA) of all domestic species, their paternal lineages are extremely homogeneous on the Y-chromosome. In order to address their huge mtDNA variation and the origin and history of maternal lineages in domestic horses, we analyzed 1961 partial d-loop sequences from 207 ancient remains and 1754 modern horses. The sample set ranged from Alaska and North East Siberia to the Iberian Peninsula and from the Late Pleistocene to modern times. We found a panmictic Late Pleistocene horse population ranging from Alaska to the Pyrenees. Later, during the Early Holocene and the Copper Age, more or less separated sub-populations are indicated for the Eurasian steppe region and Iberia. Our data suggest multiple domestications and introgressions of females especially during the Iron Age. Although all Eurasian regions contributed to the genetic pedigree of modern breeds, most haplotypes had their roots in Eastern Europe and Siberia. We found 87 ancient haplotypes (Pleistocene to Mediaeval Times); 56 of these haplotypes were also observed in domestic horses, although thus far only 39 haplotypes have been confirmed to survive in modern breeds. Thus, at least seventeen haplotypes of early domestic horses have become extinct during the last 5,500 years. It is concluded that the large diversity of mtDNA lineages is not a product of animal breeding but, in fact, represents ancestral variability.  相似文献   

15.
We assessed the molecular genetic diversity and population structure of Amaranthus species accessions using 11 simple sequence repeat markers. A total of 122 alleles were detected, and the number of alleles per marker (NA) ranged from 6 to 21 with an average of 11.1 alleles. The frequency of major alleles per locus ranged from 0.148 to 0.695, with an average value of 0.496 per marker. The overall polymorphic information content values were 0.436–0.898, with an average value of 0.657. The observed heterozygosity (HO) and expected heterozygosity (HE) ranged from 0.056 to 0.876 and from 0.480 to 0.907, with average values of 0.287 and 0.698, respectively. The average HO (0.240) was lower than the HE and gene flow (Nm), and showed substantial genetic variability among all populations of amaranth accessions. The sample groupings did not strictly follow the geographic affiliations of the accessions. A similar pattern was obtained using model-based structure analysis without grouping by species type. Knowledge of the genetic diversity and population structure of amaranth can be used to select representative genotypes and manage Amaranthus germplasm breeding programs.  相似文献   

16.
为了解云南莲瓣兰(Cymbidium tortisepalum)的遗传多样性,利用SSR技术对32个莲瓣兰主栽品种进行遗传变异分析,并构建莲瓣兰栽培品种的指纹图谱。结果表明,筛选出的12对多态性高、稳定性好的引物共检测到95个等位基因,每对引物检测到4~18个等位基因,有效等位基因数(N E)为61.489,平均有效等位基因数(NA)为5.124,Shannon信息指数(I)和多态性信息含量(PIC)分别为0.806~2.624和0.789~0.953。12对引物中,以引物SSR03的等位基因数、NE、观测杂合度、I和PIC最高。32个品种在12对引物上都具有不同的特异性条带,可以彼此区别。从12对引物中筛选出3对核心引物SSR02、SSR03和SSR12构建了莲瓣兰主栽品种SSR分子指纹图谱,这3对核心引物组合即可鉴定32个莲瓣兰栽培品种。这为莲瓣兰的品种鉴定、遗传多样性分析和分子育种研究提供理论基础和技术支持。  相似文献   

17.
The Horn of Africa forms one of the two main historical entry points of domestics into the continent and Ethiopia is particularly important in this regard. Through the analysis of mitochondrial DNA (mtDNA) d‐loop region in 309 individuals from 13 populations, we reveal the maternal genetic variation and demographic dynamics of Ethiopian indigenous goats. A total of 174 variable sites that generated 231 haplotypes were observed. They defined two haplogroups that were present in all the 13 study populations. Reference haplotypes from the six globally defined goat mtDNA haplogroups show the two haplogroups present in Ethiopia to be A and G, the former being the most predominant. Although both haplogroups are characterized by an increase in effective population sizes (Ne) predating domestication, they also have experienced a decline in Ne at different time periods, suggesting different demographic histories. We observed seven haplotypes, six were directly linked to the central haplotypes of the two haplogroups and one was central to haplogroup G. The seven haplotypes were common between Ethiopia, Kenya, Egypt, and Saudi Arabia populations, suggesting common maternal history and the introduction of goats into East Africa via Egypt and the Arabian Peninsula, respectively. While providing new mtDNA data from a historically important region, our results suggest extensive intermixing of goats mediated by human socio‐cultural and economic interactions. These have led to the coexistence of the two haplogroups in different geographic regions in Ethiopia resulting in a large caprine genetic diversity that can be exploited for genetic improvement.  相似文献   

18.
The extent of genetic diversity loss and former connectivity between fragmented populations are often unknown factors when studying endangered species. While genetic techniques are commonly applied in extant populations to assess temporal and spatial demographic changes, it is no substitute for directly measuring past diversity using ancient DNA (aDNA). We analysed both mitochondrial DNA (mtDNA) and nuclear microsatellite loci from 64 historical fossil and skin samples of the critically endangered Western Australian woylie (Bettongia penicillata ogilbyi), and compared them with 231 (= 152 for mtDNA) modern samples. In modern woylie populations 15 mitochondrial control region (CR) haplotypes were identified. Interestingly, mtDNA CR data from only 29 historical samples demonstrated 15 previously unknown haplotypes and detected an extinct divergent clade. Through modelling, we estimated the loss of CR mtDNA diversity to be between 46% and 91% and estimated this to have occurred in the past 2000–4000 years in association with a dramatic population decline. In addition, we obtained near‐complete 11‐loci microsatellite profiles from 21 historical samples. In agreement with the mtDNA data, a number of ‘new’ microsatellite alleles was only detected in the historical populations despite extensive modern sampling, indicating a nuclear genetic diversity loss >20%. Calculations of genetic diversity (heterozygosity and allelic rarefaction) showed that these were significantly higher in the past and that there was a high degree of gene flow across the woylie's historical range. These findings have an immediate impact on how the extant populations are managed and we recommend the implementation of an assisted migration programme to prevent further loss of genetic diversity. Our study demonstrates the value of integrating aDNA data into current‐day conservation strategies.  相似文献   

19.
Ctenomys (tuco‐tuco) is the most numerous genus of South American subterranean rodents and one of the most genetically diverse clades of mammals known. In particular, the genus constitutes a very interesting model for evolutionary studies of genetic divergence and conservation. Ctenomys magellanicus is the southernmost species of the group and the only one living in Isla Grande de Tierra del Fuego (Argentina). This species presents two chromosomal forms (Cm34 and Cm36) fragmented into demes distributed from the north region (steppe) to the south region (ecotone) of the island, respectively; no hybrids or overlapping areas were detected. To study the historical demography and the spatial genetic structure of the C. magellanicus population we used mitochondrial DNA (mtDNA) (D‐loop and cytochrome b) and microsatellite loci. Nine mtDNA haplotypes were identified, three of them belonging to the north and the other six to the south. Shared haplotypes between regions were not detected. mtDNA and microsatellite genotypes showed a marked pattern of population structure with low values of genetic flow between regions. The south is made up of small populations or isolated demes making up an endogamic metapopulation with unique alleles and haplotypes. Also, the results suggest a northward expansion process starting from an ancestral haplotype from the south. That population might have lived at a refuge through the adverse Pleistocene environmental conditions that took place at Tierra del Fuego. Results of this study are relevant to the conservation of C. magellanicus, suggesting that each region (north and south) might be considered as an Evolutionarily Significant Unit. © 2013 The Linnean Society of London  相似文献   

20.
选择12对微卫星标记检测了于2011年采集自元江(红河上游中国江段)5个样点192尾鲤的群体遗传多样性.共检测到201个等位基因,每个位点等位基因2-27个.各群体各位点平均等位基因(NA)12.25-14.67个,平均有效等位基因(NE)8.28-9.73个,平均观察杂合度(Ho)o.7765-0.8037,平均期望杂合度(HE)0.7761-0.8080,平均多态信息含量(PIC)0.7534-0.7843.元江鲤种群192个个体各位点NA、NE、Ho、HE、PIC分别为16.50、11.26、0.7927、0.8049、0.7966,种群遗传多样性水平高.元江鲤群体之间遗传分化小,可作为一个种群管理单元进行管理.增殖放流要防止遗传多样性丧失.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号