Genome-wide analysis of the world’s sheep breeds reveals high levels of historic mixture and strong recent selection

L’analyse des races des moutons du monde à l'échelle du génome révèle un mélange historique de haut niveau et une forte sélection récente

James W. Kijas (1) , Johannes A. Lenstra (2) , Ben Hayes (3) , Simon S. Boitard (4) , Laercio R. Porto Neto (1) , Magali San Cristobal (4) , Bertrand Servin (4) , Russell Mcculloch (5) , Vicki Whan (1) , Kimberly Gietzen (6) , Samuel Paiva (7) , William Barendse (1) , Elena Ciani (8) , Herman Raadsma (9) , John Mcewan (10) , Brian Dalrymple (1) , . International Sheep Genomics Consortium

1 Livestock Industries
2 Faculty of Veterinary Medicine
3 Department of Primary Industries
4 LGC - Laboratoire de Génétique Cellulaire
5 CSIRO - Commonwealth Scientific and Industrial Research Organisation [Canberra]
6 Illumina
7 Genetic Resources and Biotechnology
8 UNIBA - Università degli studi di Bari Aldo Moro = University of Bari Aldo Moro
9 Faculty of Veterinary Science
10 Invermay Agricultural Center

Through their domestication and subsequent selection, sheep have been adapted to thrive in a diverse range of environments. To characterise the genetic consequence of both domestication and selection, we genotyped 49,034 SNP in 2,819 animals from a diverse collection of 74 sheep breeds. We find the majority of sheep populations contain high SNP diversity and have retained an effective population size much higher than most cattle or dog breeds, suggesting domestication occurred from a broad genetic base. Extensive haplotype sharing and generally low divergence time between breeds reveal frequent genetic exchange has occurred during the development of modern breeds. A scan of the genome for selection signals revealed 31 regions containing genes for coat pigmentation, skeletal morphology, body size, growth, and reproduction. We demonstrate the strongest selection signal has occurred in response to breeding for the absence of horns. The high density map of genetic variability provides an in-depth view of the genetic history for this important livestock species.

Mots clés: sheep; genetic diversity; high density genotyping; selection signature

Domaines: Sciences du Vivant [q-bio]

James W. Kijas, Johannes A. Lenstra, Ben Hayes, Simon S. Boitard, Laercio R. Porto Neto, et al.. Genome-wide analysis of the world’s sheep breeds reveals high levels of historic mixture and strong recent selection. PLoS Biology, 2012, 10, online (2), Non paginé. ⟨10.1371/journal.pbio.1001258⟩. ⟨hal-02652546⟩