Search

A recent work investigating genetic origin, admixture and population history of primitive European cattle highlighted, by using genome-wide single nucleotide polymorphisms, zebu gene flow in the Balkan and Italian Podolic cattle populations. Haemoglobin protein polymorphism analysis in Italian breeds highlighted the presence of zebuine markers in both Italian Podolic and Alpine Grey cattle. Based on the above evidences, we here specifically look for genomic regions of zebuine ancestry in a different dataset of 50K genotypes from Mediterranean breeds including 29 Marismena (Spain); 30 Bazadaise and 30 Gasconne (France); 24 Alpine Grey, 97 Piemontese, 51 Chianina, 5 Marchigiana, 121 Romagnola, 24 Podolica, 24 Modenese, 30 Reggiana, 30 Cinisara and 30 Modicana (Italy); 24 Guelmoise (Algeria); 24 Cika (Slovenia), 43 Illyrian Mountain Buša (Albania). Additional taurine and zebuine breeds from previously published studies are also included in the analyses. Special emphasis in genetic analyses is also given to the identification of genomic regions potentially associated with a phenotypic trait observed in several taurine breeds as well as in some zebuine breeds, characterized by calves having a fawn coat at birth, while turning to various shades of grey in adult animals. The obtained results contribute to a better characterization of history and genetic structure of Mediterranean cattle breeds.

International audience; Genomic regions subjected to selection frequently show signatures such as within-population reduced nucleotide diversity and outlier values of differentiation among differentially selected populations. In this study, we analyzed 50K SNP genotype data of 373 animals belonging to 23 sheep breeds of different geographic origins using the Rsb (extended haplotype homozygosity) and FST statistical approaches, to identify loci associated with the fat-tail phenotype. We also checked if these putative selection signatures overlapped with regions of high-homozygosity (ROH). The analyses identified novel signals and confirmed the presence of selection signature in genomic regions that harbor candidate genes known to affect fat deposition. Several genomic regions that frequently appeared in ROH were also identified within each breed, but only two ROH islands overlapped with the putative selection signatures. The results reported herein provide the most complete genome-wide study of selection signatures for fat-tail in African and Eurasian sheep breeds; they also contribute insights into the genetic basis for the fat tail phenotype in sheep, and confirm the great complexity of the mechanisms that underlie quantitative traits, such as the fat-tail.