80 research outputs found
Hierarchical structure of the Sicilian goats revealed by Bayesian analyses of microsatellite information
Genetic structure and relationship amongst the main goat populations in Sicily (Girgentana, Derivata di Siria, Maltese and Messinese) were analysed using information from 19 microsatellite markers genotyped on 173 individuals. A posterior Bayesian approach implemented in the program STRUCTURE revealed a hierarchical structure with two clusters at the first level (Girgentana vs. Messinese, Derivata di Siria and Maltese), explaining 4.8% of variation (AMOVA ФST estimate). Seven clusters nested within these first two clusters (further differentiations of Girgentana, Derivata di Siria and Maltese), explaining 8.5% of variation (AMOVA ФSC estimate). The analyses and methods applied in this study indicate their power to detect subtle population structure
Inbreeding, Microsatellite Heterozygosity, and Morphological Traits in Lipizzan Horses
While the negative effects of inbreeding and reduced heterozygosity on fecundity and survival are well established, only a few investigations have been carried out concerning their influence on morphological traits. This topic is of particular interest for a small and closed population such as the Lipizzan horse. Thus, 27 morphological traits were measured in 360 Lipizzan mares and were regressed on the individual inbreeding coefficients, as well as on the individual heterozygosity and mean squared distances (mean d2) between microsatellite alleles within an individual. Both individual heterozygosity and mean d2 were based on 17 microsatellite loci dispersed over 14 chromosomes. The results obtained by multivariate analysis reveal significant effects of stud (P <.0001), age at measurement (P <.0001), and mean d2 (P =.0143). In univariate analyses, significant associations were obtained between length of pastern-hindlimbs and inbreeding coefficient (P <.01), length of cannons-hindlimb and mean d2 (P <.01), and length of neck and mean d2 (P <.001). After adjustment of single-test P values for multiple tests (Hochberg's step-up Bonferroni method), only the association of the length of neck and mean d2 remained significant (P =.0213). Thus, no overall large effects of inbreeding, microsatellite heterozygosity, and mean d2 on morphological traits were observed in the Lipizzan hors
Inbreeding, Microsatellite Heterozygosity, and Morphological Traits in Lipizzan Horses
While the negative effects of inbreeding and reduced heterozygosity on fecundity and survival are well established, only a few investigations have been carried out concerning their influence on morphological traits. This topic is of particular interest for a small and closed population such as the Lipizzan horse. Thus, 27 morphological traits were measured in 360 Lipizzan mares and were regressed on the individual inbreeding coefficients, as well as on the individual heterozygosity and mean squared distances (mean d2) between microsatellite alleles within an individual. Both individual heterozygosity and mean d2 were based on 17 microsatellite loci dispersed over 14 chromosomes. The results obtained by multivariate analysis reveal significant effects of stud (P <.0001), age at measurement (P <.0001), and mean d2 (P =.0143). In univariate analyses, significant associations were obtained between length of pastern-hindlimbs and inbreeding coefficient (P <.01), length of cannons-hindlimb and mean d2 (P <.01), and length of neck and mean d2 (P <.001). After adjustment of single-test P values for multiple tests (Hochberg's step-up Bonferroni method), only the association of the length of neck and mean d2 remained significant (P =.0213). Thus, no overall large effects of inbreeding, microsatellite heterozygosity, and mean d2 on morphological traits were observed in the Lipizzan horse
Multiple paternal origins of domestic cattle revealed by Y-specific interspersed multilocus microsatellites
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Population structure and genetic history of Tibetan Terriers
International audienceAbstractBackgroundTibetan Terrier is a popular medium-sized companion dog breed. According to the history of the breed, the western population of Tibetan Terriers includes two lineages, Lamleh and Luneville. These two lineages derive from a small number of founder animals from the native Tibetan Terrier population, which were brought to Europe in the 1920s. For almost a century, the western population of Tibetan Terriers and the native population in Tibet were reproductively isolated. In this study, we analysed the structure of the western population of Tibetan Terriers, the original native population from Tibet and of different crosses between these two populations. We also examined the genetic relationships of Tibetan Terriers with other dog breeds, especially terriers and some Asian breeds, and the within-breed structure of both Tibetan Terrier populations.ResultsOur analyses were based on high-density single nucleotide polymorphism (SNP) array (Illumina HD Canine 170 K) and microsatellite (18 loci) genotypes of 64 Tibetan Terriers belonging to different populations and lineages. For the comparative analysis, we used 348 publicly available SNP array genotypes of dogs from other breeds. We found that the western population of Tibetan Terriers and the native Tibetan Terriers clustered together with other Asian dog breeds, whereas all other terrier breeds were grouped into a separate group. We were also able to differentiate the western Tibetan Terrier lineages (Lamleh and Luneville) from the native Tibetan Terrier population.ConclusionsOur results reveal the relationships between the western and native populations of Tibetan Terriers and support the hypothesis that Tibetan Terrier belongs to the group of ancient dog breeds of Asian origin, which are close to the ancestors of the modern dog that were involved in the early domestication process. Thus, we were able to reject the initial hypothesis that Tibetan Terriers belong to the group of terrier breeds. The existence of this native population of Tibetan Terriers at its original location represents an exceptional and valuable genetic resource
Assessment of autozygosity in Nellore cows (Bos indicus) through high-density SNP genotypes.
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Inbreeding and purging at the genomic level: the Chillingham cattle reveal extensive, non-random SNP heterozygosity
Local breeds of livestock are of conservation significance as components of global
biodiversity and as reservoirs of genetic variation relevant to the future sustainability of
agriculture. One such rare historic breed, the Chillingham cattle of northern England, has a
350-year history of isolation and inbreeding yet shows no diminution of viability or fertility.
The Chillingham cattle have not been subjected to selective breeding. It has been suggested
previously that the herd has minimal genetic variation. In this study, high-density SNP
genotyping with the 777K SNP chip showed that 9.1% of loci on the chip are polymorphic
in the herd, compared with 62–90% seen in commercial cattle breeds. Instead of being
homogeneously distributed along the genome, these loci are clustered at specific
chromosomal locations. A high proportion of the Chillingham individuals examined were
heterozygous at many of these polymorphic loci, suggesting that some loci are under
balancing selection. Some of these frequently heterozygous loci have been implicated as sites
of recessive lethal mutations in cattle. Linkage disequilibrium equal or close to 100% was
found to span up to 1350 kb, and LD was above r2 = 0.25 up to more than 5000 kb. This
strong LD is consistent with the lack of polymorphic loci in the herd. The heterozygous
regions in the Chillingham cattle may be the locations of genes relevant to fitness or
survival, which may help elucidate the biology of local adaptation in traditional breeds and
facilitate selection for such traits in commercial cattle
Nonequivalent lethal equivalents : Models and inbreeding metrics for unbiased estimation of inbreeding load
We thank Peter Arcese, A. Bradley Duthie, Richard Frankham, Christine Grossen, Catherine Grueber, Marty Kardos, and three anonymous reviewers for helpful comments and discussion on earlier versions of this manuscript. We thank Cate Lessels and Peter Boag from whose 1987 paper in The Auk we copied the idea for the title of this paper. Our work was supported by a Swiss National Science Foundation grant (31003A-116794) to LFK, the Forschungskredit of the University of Zurich (FK-15-104) and a Swiss National Science Foundation grant (P2ZHP3_168447) to PN, and JMR was supported by a European Research Council grant.Peer reviewedPublisher PD
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