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1.
The canine major histocompatibility complex contains highly polymorphic genes, many of which are critical in regulating immune response. Since domestic dogs evolved from Gray Wolves (Canis lupus), common DLA class II alleles should exist. Sequencing was used to characterize 175 Gray Wolves for DLA class II alleles, and data from 1856 dogs, covering 85 different breeds of mostly European origin, were available for comparison. Within wolves, 28 new alleles were identified, all occurring in at least 2 individuals. Three DLA-DRB1, 8 DLA-DQA1, and 6 DLA-DQB1 alleles also identified in dogs were present. Twenty-eight haplotypes were identified, of which 2 three-locus haplotypes, and many DLA-DQA1/DQB1 haplotypes, are also found in dogs. The wolves studied had relatively few dog DLA alleles and may therefore represent a remnant population descended from Asian wolves. The single European wolf included carried a haplotype found in both these North American wolves and in many dog breeds. Furthermore, one wolf DQB1 allele has been found in Shih Tzu, a breed of Asian origin. These data suggest that the wolf ancestors of Asian and European dogs may have had different gene pools, currently reflected in the DLA alleles present in dog breeds.  相似文献   

2.
The genetic diversity of the casein locus in cattle was studied on the basis of haplotype analysis. Consideration of recently described genetic variants of the casein genes which to date have not been the subject of diversity studies, allowed the identification of new haplotypes. Genotyping of 30 cattle breeds from four continents revealed a geographically associated distribution of haplotypes, mainly defined by frequencies of alleles at CSN1S1 and CSN3. The genetic diversity within taurine breeds in Europe was found to decrease significantly from the south to the north and from the east to the west. Such geographic patterns of cattle genetic variation at the casein locus may be a result of the domestication process of modern cattle as well as geographically differentiated natural or artificial selection. The comparison of African Bos taurus and Bos indicus breeds allowed the identification of several Bos indicus specific haplotypes (CSN1S1*C-CSN2*A2-CSN3*AI/CSN3*H) that are not found in pure taurine breeds. The occurrence of such haplotypes in southern European breeds also suggests that an introgression of indicine genes into taurine breeds could have contributed to the distribution of the genetic variation observed.  相似文献   

3.
Scrapie eradication efforts cost 18 million dollars annually in the United States and rely heavily upon PRNP genotyping of sheep. Genetic resistance might reduce goat scrapie and limit the risk of goats serving as a scrapie reservoir, so PRNP coding sequences were examined from 446 goats of 10 breeds, 8 of which had not been previously examined at PRNP. The 10 observed alleles were all related to one of two central haplotypes by a single amino acid substitution. At least five of these alleles (M142, R143, S146, H154, and K222) have been associated with increased incubation time or decreased odds of scrapie. To the best of our knowledge, neither S146 nor K222 has been found in any goats with scrapie, though further evaluation will be required to demonstrate true resistance. S146 was more common, present in several breeds at widely varying frequencies, while K222 was observed only in two dairy breeds at low frequency. Overall, this study provides frequency data on PRNP alleles in US goats, shows the pattern of relationships between haplotypes, and demonstrates segregation of multiple scrapieassociated alleles in several breeds not examined before at PRNP.  相似文献   

4.
Genetic variants of bovine milk proteins have been intensively used to characterize breeds and as markers for population/QTL studies throughout the world. However, a large number of cattle breeds including those found in Portugal, remain unstudied. In this work, we have analysed the genetic variation of six milk protein loci in 10 Portuguese cattle breeds by isoelectric focusing. High genetic diversities were generally found across breeds, with the exception of Mirandesa that showed a trend to fixation of the most common alleles in five loci, as well as of the rarer CSN3B allele. The casein haplotype BA2A was often the most frequent, followed by haplotypes BA2B and BA1A. Remarkably, CA2A was found to be the second most frequent haplotype in Southern breeds, supporting a geographical cline between Central-Northern European breeds and Bos indicus populations. Our data suggest that high genetic similarity among neighbouring Portuguese breeds is mainly caused by gene flow, and that the geographical distribution of particular casein haplotypes may indicate an influence of African cattle.  相似文献   

5.
This survey represents the first characterization of mitochondrial DNA diversity within three breeds of Indian sheep (two strains of the Deccani breed, as well as the Bannur and Garole breeds) from different geographic regions and with divergent phenotypic characteristics. A 1061-bp fragment of the mitochondrial genome spanning the control region, a portion of the 12S rRNA gene and the complete phenyl tRNA gene, was sequenced from 73 animals and compared with the corresponding published sequence from European and Asian breeds and the European Mouflon (Ovis musimon). Analysis of all 156 sequences revealed 73 haplotypes, 52 of which belonged to the Indian breeds. The three Indian breeds had no haplotypes in common, but one Indian haplotype was shared with European and other Asian breeds. The highest nucleotide and haplotype diversity was observed in the Bannur breed (0.00355 and 0.981 respectively), while the minimum was in the Sangamneri strain of the Deccani breed (0.00167 and 0.882 respectively). All 52 Indian haplotypes belonged to mitochondrial lineage A. Therefore, these Indian sheep are distinct from other Asian and European breeds studied so far. The relationships among the haplotypes showed strong breed structure and almost no introgression among these Indian breeds, consistent with Indian sheep husbandry, which discourages genetic exchange between breeds. These results have implications for the conservation of India's ovine biodiversity and suggest a common origin for the breeds investigated.  相似文献   

6.
Early pig farmers in Europe imported Asian pigs to cross with their local breeds in order to improve traits of commercial interest. Current genomics techniques enabled genome-wide identification of these Asian introgressed haplotypes in modern European pig breeds. We propose that the Asian variants are still present because they affect phenotypes that were important for ancient traditional, as well as recent, commercial pig breeding. Genome-wide introgression levels were only weakly correlated with gene content and recombination frequency. However, regions with an excess or absence of Asian haplotypes (AS) contained genes that were previously identified as phenotypically important such as FASN, ME1, and KIT. Therefore, the Asian alleles are thought to have an effect on phenotypes that were historically under selection. We aimed to estimate the effect of AS in introgressed regions in Large White pigs on the traits of backfat (BF) and litter size. The majority of regions we tested that retained Asian deoxyribonucleic acid (DNA) showed significantly increased BF from the Asian alleles. Our results suggest that the introgression in Large White pigs has been strongly determined by the selective pressure acting upon the introgressed AS. We therefore conclude that human-driven hybridization and selection contributed to the genomic architecture of these commercial pigs.  相似文献   

7.
Recent studies presenting genetic analysis of dog breeds do not focus specifically on genetic relationships among pointing dog breeds, although hunting was among the first traits of interest when dogs were domesticated. This report compares histories with genetic relationships among five modern breeds of pointing dogs (English Setter, English Pointer, Epagneul Breton, Deutsch Drahthaar and German Shorthaired Pointer) collected in Spain using mitochondrial, autosomal and Y-chromosome information. We identified 236 alleles in autosomal microsatellites, four Y-chromosome haplotypes and 18 mitochondrial haplotypes. Average F ST values were 11.2, 14.4 and 13.1 for autosomal, Y-chromosome microsatellite markers and mtDNA sequence respectively, reflecting relatively high genetic differentiation among breeds. The high gene diversity observed in the pointing breeds (61.7–68.2) suggests contributions from genetically different individuals, but that these individuals originated from the same ancestors. The modern English Setter, thought to have arisen from the Old Spanish Pointer, was the first breed to cluster independently when using autosomal markers and seems to share a common maternal origin with the English Pointer and German Shorthaired Pointer, either via common domestic breed females in the British Isles or through the Old Spanish Pointer females taken to the British Isles in the 14th and 16th centuries. Analysis of mitochondrial DNA sequence indicates the isolation of the Epagneul Breton, which has been formally documented, and shows Deutsch Drahthaar as the result of crossing the German Shorthaired Pointer with other breeds. Our molecular data are consistent with historical documents.  相似文献   

8.
Pim-1, a putative oncogene involved in T-cell lymphomagenesis, was mapped between the pseudo-alpha globin gene Hba-4ps and the alpha-crystallin gene Crya-1 on mouse chromosome 17 and therefore within the t complex. Pim-1 restriction fragment variants were identified among t haplotypes. Analysis of restriction fragment sizes obtained with 12 endonucleases demonstrated that the Pim-1 genes in some t haplotypes were indistinguishable from the sizes for the Pim-1b allele in BALB/c inbred mice. There are now three genes, Pim-1, Crya-1 and H-2 I-E, that vary among independently derived t haplotypes and that have indistinguishable alleles in t haplotypes and inbred strains. These genes are closely linked within the distal inversion of the t complex. Because it is unlikely that these variants arose independently in t haplotypes and their wild-type homologues, we propose that an exchange of chromosomal segments, probably through double crossingover, was responsible for indistinguishable Pim-1 genes shared by certain t haplotypes and their wild-type homologues. There was, however, no apparent association between variant alleles of these three genes among t haplotypes as would be expected if a single exchange introduced these alleles into t haplotypes. If these variant alleles can be shown to be identical to the wild-type allele, then lack of association suggests that multiple exchanges have occurred during the evolution of the t complex.  相似文献   

9.
The sheep (Ovis aries L.) has been an important farm animal species since its domestication. A wide array of indigenous sheep breeds with abundant phenotypic diversity exists for domestication and selection. Therefore, assessing the genetic diversity of a local sheep resource using a multi-molecular system is helpful for maintaining and conserving those breeds. This study aimed to investigate the genetic diversity of three native Chinese sheep breeds (Tibetan sheep, Sishui Fur sheep, and Small-tailed Han sheep) using 15 microsatellite markers and the second exon of the DRA gene. In regards to the microsatellites, on average, 19 alleles per loci were observed among all individuals. Across loci, the HO within the population was 0.652 ± 0.022 in Tibetan sheep, 0.603 ± 0.023 in Small-tailed Han sheep and 0.635 ± 0.022 in SFS, and for most populations, the H E and H O were inconsistent. In addition, affluent private alleles within the breed indicated that the breeds have different domestication histories or sites. In regards to the 2 exon of the DRA gene, three haplotypes were constructed by seven single-nucleotide polymorphisms (SNPs), which were identified in the second DRA exon and inferred the potential for phenotypic variety in these Chinese native sheep. In summary, the current study reveals the importance of implementing effective conservation strategies for these three native Chinese sheep.  相似文献   

10.
Domestic sheep in Kazakhstan may provide an interesting source of genetic variability due to their proximity to the center of domestication and the Silk Route. Additionally, those breeds have never been compared to New World sheep populations. This report compares genetic diversity among five Kazakhstan (KZ) and 13 United States (US) sheep breeds (N = 442) using 25 microsatellite markers from the FAO panel. The KZ breeds had observed and expected measures of heterozygosity greater than 0.60 and an average number of alleles per locus of 7.8. In contrast, US sheep breeds had observed heterozygosity ranged from 0.37 to 0.62 and had an average number of alleles of 5.7. A Bayesian analysis indicated there were two primary populations (K = 2). Surprisingly, the US breeds were near evenly split between the two clusters, while all of the KZ breeds were placed in one of the two clusters. Pooling breeds within country of sample origin showed KZ and US populations to have similar levels of expected heterozygosity and the average number of alleles per locus. The results of breeds pooled within country suggest that there was no difference between countries for these diversity measures using this set of neutral markers. This finding suggests that populations’ geographically isolated from centers of domestication can be more diverse than previously thought, and as a result, conservation strategies can be adjusted accordingly. Furthermore, these results suggest there may be limited need for countries to alter the protocols for trade and exchange of animal genetic resources that are in place today, since no one population has a unique set of private alleles.  相似文献   

11.
The CGG repeat within the X-chromosome-linked FMR1 gene, which in hyperexpansion (> 200 copies) results in fragile X syndrome, is highly polymorphic. The mechanism of expansion is not well understood, but CGG repeats called intermediate-length or gray zone alleles (approximately equal 35-60 repeats) are thought to make up the FMR1 alleles showing initial steps in this expansion process. It has been hypothesized that the background haplotype of these alleles plays a role in their susceptibility to expansion. In this study we investigate whether or not the frequencies of alleles and haplotypes at four marker loci in the FMR1 gene region (microsatellites DXS548 and FRAXAC1 and SNPs ATL1 and FMRb) in 84 intermediate-length male chromosomes differ from those in 94 common-size male alleles. The ATL1*G and FMRB*A alleles were more frequent among intermediate-length alleles than among common alleles. In addition, the DXS548-FRAXAC1 T50-T42 and T40-T42 haplotypes were strongly associated with intermediate-length alleles between 41 and 60 CGG repeats (p < 0.001). Two extended haplotypes, DXS548-FRAXAC1-ATL1-FMRb T50-T42-G-A and T40-T42-G-A, are strongly associated (p < 0.001) with intermediate-length alleles between 41 and 60 CGG repeats, and these haplotypes have also been reported as fragile X associated haplotypes in European populations. These data suggest that these haplotypes are among the most susceptible to further expansion among the intermediate-length alleles. T50-T42-G-A was also much more prevalent in males with 35-40 CGG repeats than in males with common-size alleles. ATL1 did not increase discrimination among intermediate-length alleles beyond that detected by DXS548-FRAXAC1 haplotypes, but the FMRb locus did, particularly for the DXS548-FRAXAC1-ATL1 T50-T42-G and T40-T42-G haplotypes. Comparison with fragile X associated haplotypes, from the literature, suggests that repeat hyperexpansion occurs most frequently on chromosomes carrying FMRB*A. Within the intermediate-length allele category, however, there were some significant differences in haplotype frequencies between smaller and larger alleles, and this finding has implications for future studies.  相似文献   

12.
Polymorphism of PBRs of the major histocompatibility complex (MHC) genes is well recognized, but the polymorphism also extends to proximal promoter regions. Examining DQB1 variability in dogs and wolves, we identified 7 promoter variants and 13 exon 2 alleles among 89 dogs, including a previously unknown DQB1 exon 2 allele, and 8 promoter variants and 9 exon 2 alleles among 85 wolves. As expected from previous studies and from a close chromosomal location, strong linkage disequilibrium was demonstrated in both wolves and dogs by having significantly fewer promoter/exon 2 combinations than expected from simulations of randomized data sets. Interestingly, we noticed weaker haplotypic associations in dogs than in wolves. Dogs had twice as many promoter/exon 2 combinations as wolves and an almost 2-fold difference in the number of exon 2 alleles per promoter variant. This difference was not caused by an admixture of breeds in our group of dogs because the high ratio of observed to expected number of haplotypes persisted within a single dog breed, the German Shepherd. Ewens-Watterson tests indicated that both the promoter and exon 2 are under the balancing selection, and both regions appear to be more recently derived in the dog than in the wolf. Hence, although reasons for the differences are unknown, they may relate to altered selection pressure on patterns of expression. Deviations from normal MHC expression patterns have been associated with autoimmune diseases, which occur frequently in several dog breeds. Further knowledge about these deviations may help us understand the source of such diseases.  相似文献   

13.
We have previously reported that several of theRLA haplotypes of our rabbits have anRLA-D allele in common, i. e., they fail to cross stimulate in the MLC test. To investigate the possibility that these haplotypes originated in unrelated animals, a panel of homozygous rabbits was selected to partially characterize noninbred rabbits from five commercial sources for their alleles at theRLA-D locus. In the 47 rabbits tested, 4 homozygous animals and 12 heterozygous animals were detected with the four alleles chosen for typing. At least two independent pairs of rabbits shared identicalRLA-D genotypes. Our results indicate that theRLA-D locus is not extremely polymorphic and that rabbits cannot be assumed to be completely mismatched for theRLA complex simply because they are from different breeds or from independent suppliers.  相似文献   

14.

Background

Diversity patterns of livestock species are informative to the history of agriculture and indicate uniqueness of breeds as relevant for conservation. So far, most studies on cattle have focused on mitochondrial and autosomal DNA variation. Previous studies of Y-chromosomal variation, with limited breed panels, identified two Bos taurus (taurine) haplogroups (Y1 and Y2; both composed of several haplotypes) and one Bos indicus (indicine/zebu) haplogroup (Y3), as well as a strong phylogeographic structuring of paternal lineages.

Methodology and Principal Findings

Haplogroup data were collected for 2087 animals from 138 breeds. For 111 breeds, these were resolved further by genotyping microsatellites INRA189 (10 alleles) and BM861 (2 alleles). European cattle carry exclusively taurine haplotypes, with the zebu Y-chromosomes having appreciable frequencies in Southwest Asian populations. Y1 is predominant in northern and north-western Europe, but is also observed in several Iberian breeds, as well as in Southwest Asia. A single Y1 haplotype is predominant in north-central Europe and a single Y2 haplotype in central Europe. In contrast, we found both Y1 and Y2 haplotypes in Britain, the Nordic region and Russia, with the highest Y-chromosomal diversity seen in the Iberian Peninsula.

Conclusions

We propose that the homogeneous Y1 and Y2 regions reflect founder effects associated with the development and expansion of two groups of dairy cattle, the pied or red breeds from the North Sea and Baltic coasts and the spotted, yellow or brown breeds from Switzerland, respectively. The present Y1-Y2 contrast in central Europe coincides with historic, linguistic, religious and cultural boundaries.  相似文献   

15.
16.
Two divergent routes of evolution gave rise to the DRw13 haplotypes   总被引:1,自引:0,他引:1  
The HLA class II genes and haplotypes have evolved over a long period of evolutionary time by mechanisms such as gene conversion, reciprocal recombination and point mutation. The extent of the diversity generated is most clearly evident in an analysis of the HLA class II alleles present within DRw13 haplotypes. This study uses cDNA sequencing to examine the first domains of DRB1, DRB3, DQA1, and DQB1 alleles from several American black individuals expressing seven different DRw13 haplotypes, five with undefined HLA-D specificities (i.e., not Dw18 or Dw19). Two new DRw13 alleles described in this study are the first examples of convergent evolution of DR alleles in which gene conversion has apparently combined segments of DRB1 alleles encoding DRw11 and DRw8 to generate two new DRB1 alleles, DRB1*1303 and DRB1*1304, that encode molecules bearing serologic determinants of a third allele, DRw13. These new DRw13 alleles are found embedded in haplotypes of DRw11 origin distinct from haplotypes encoding previously identified DRw13 alleles, DRB1*1301 and DRB1*1302. These data suggest that two evolutionary pathways may have given rise to two subgroups of alleles encoding molecules that share DRw13 serologic determinants yet which possess different structural and, likely, functional motifs. Reciprocal gene recombination events resulting in different DR, DRw52 and DQ allele combinations also appear to have played a crucial role in augmenting the level of diversity found in DRw13 haplotypes. Recombination has resulted in the association of one of the new DRw13 alleles with a DQw2 allele normally found associated with DR7 and the association of the DRw52c-associated DRw13 allele (DRB1*1302) with three different DQw1 alleles. The seven DRw13 haplotypes that have resulted from the effect of recombination on haplotypes formed by the two pathways of DRw13 allelic diversification have resulted in different repertoires of class II molecules and, most likely, different immune response profiles in individuals with these haplotypes.  相似文献   

17.
Y chromosome haplotype analysis in purebred dogs   总被引:3,自引:0,他引:3  
In order to evaluate the genetic structure of purebred dogs, six Y chromosome microsatellite markers were used to analyze DNA samples from 824 unrelated dogs from 50 recognized breeds. A relatively small number of haplotypes (67) were identified in this large sample set due to extensive sharing of haplotypes between breeds and low haplotype diversity within breeds. Fifteen breeds were characterized by a single Y chromosome haplotype. Breed-specific haplotypes were identified for 26 of the 50 breeds, and haplotype sharing between some breeds indicated a common history. A molecular variance analysis (AMOVA) demonstrated significant genetic variation across breeds (63.7%) and with geographic origin of the breeds (11.5%). A network analysis of the haplotypes revealed further relationships between the breeds as well as deep rooting of many of the breed-specific haplotypes, particularly among breeds of African origin.Michael J. Bannasch and Jeanne R. Ryun contributed equally to this work.  相似文献   

18.

Background

Mangalica breeds are indigenous to Hungary and their breeding history dates back to about 200–250 years ago. They are fat-type pigs and have a rare curly hair phenotype. The aim of our study was to establish the relationships between these unique breeds and other European breeds.

Results

Based on a core sequence of 382 bp present in 2713 mitochondrial D-loop sequences from pigs belonging to 38 local breeds from nine countries, five cosmopolitan breeds and wild boars from 14 countries, we identified 164 haplotypes. More than half of the 2713 sequences belonged to either four haplotypes characteristic of continental European breeds or two haplotypes characteristic of British/cosmopolitan breeds; each haplotype is present in more than 100 individuals. Most Mangalica individuals belonged either to one of these common continental European haplotypes or to two Mangalica-specific haplotypes that were absent in all other breeds. In addition, we identified the ancestral mitochondrial D-loop signature present in these 2713 sequences and found that ~ 80% carried the European ancient signatures, ANC-Aside and ANC-Cside or their closely related signatures, while most of the remaining sequences carried a modern Asian signature, ANC-Easia. Mangalica individuals carried the ANC-Aside signature, but not the ANC-Cside or ANC-Easia signatures.

Conclusions

In all the Mangalica individuals, a unique ancient European signature was found in the mitochondrial DNA D-loop region, but they belonged almost exclusively to either certain very abundant European or two Mangalica-specific D-loop haplotypes. This indicates that the present-day Mangalica population in Hungary evolved either by introgression of other European breeds and wild boars or via total isolation after the divergence of European ancient porcine bloodlines.  相似文献   

19.
DNA samples from 307 males of 13 Portuguese native cattle breeds, 57 males of the 3 major exotic breeds in Portugal (Charolais, Friesian, and Limousin), and 5 Brahman (Bos indicus) were tested for 5 single nucleotide polymorphisms, 1 "indel," and 7 microsatellites specific to the Y chromosome. The 13 Y-haplotypes defined included 3 previously described patrilines (Y1, Y2, and Y3) and 10 new haplotypes within Bos taurus. Native cattle contained most of the diversity with 7 haplotypes (H2Y1, H3Y1, H5Y1, H7Y2, H8Y2, H10Y2, and H12Y2) found only in these breeds. H6Y2 and H11Y2 occurred in high frequency across breeds including the exotics. Introgression of Friesian cattle into Ramo Grande was inferred through their sharing of haplotype H4Y1. Among the native breeds, Mertolenga had the highest haplotype diversity (0.68 +/- 0.07), Brava de Lide was the least differentiated. The analyses of molecular variance showed significant (P < 0.0001) differences between breeds with more than 64% of the total genetic variation found among breeds within groups and 33-35% within breeds. The detection of INRA189-104 allele in 8 native breeds suggested influence of African cattle in breeds of the Iberian Peninsula. The presence in Portuguese breeds of Y1 patrilines, also found in aurochs, could represent more ancient local haplotypes.  相似文献   

20.
The Eastern European Grey cattle are regarded as the direct descendants of the aurochs (Bos taurus primigenius). Nowadays in Romania, less than 100 Grey animals are being reared and included in the national gene reserve. We examined the genetic diversity among Romanian Grey, Brown, Spotted and Black and White cattle breeds, with a particular focus on Romanian Grey through the use of (i) 11 bovine specific microsatellite markers on 83 animals and (ii) 638 bp length of mitochondrial DNA (mtDNA) D-loop region sequence data from a total of 81 animals. Both microsatellite and mtDNA analysis revealed a high level of genetic variation in the studied breeds. In Romanian Grey a total of 100 alleles were found, the mean number of observed alleles per locus was 9.091; the average observed heterozygosity was 0.940; the Wright’s fixation index (FIS) was negative (-0.189) and indicates that there is no inbreeding and no selection pressure. MtDNA analysis revealed 52 haplotypes with 67 variable sites among the Romanian cattle breeds without any insertion or deletion. Haplotype diversity was 0.980 ± 0.007 and ranged from 0.883 ± 0.056 (Brown) to 0.990 ± 0.028 (Spotted and Black and White). The highest genetic variability of the mtDNA was recorded in the Grey breed, where 18 haplotypes were identified. The most frequent mtDNA D-loop region belonged to T3 haplogroup (80.247%), which was found across all studied breeds, while T2 haplotypes (16.049%) was only found in Grey, Spotted and Black and White genotypes. The T1 haplotypes (3.704%) were found in the Grey and Spotted. The current results contribute to the general knowledge on genetic diversity found in Eastern European cattle breeds and could prove a valuable tool for the conservation efforts of animal genetic resources (FAnGR).  相似文献   

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