Selection signatures in worldwide Sheep populations

Abstract

The diversity of populations in domestic species offer great opportunities to study genome response to selection. The recently published Sheep Hapmap dataset is a great example of characterization of the world wide genetic diversity in the Sheep. In this study, we re-analyzed the Sheep Hapmap dataset to identify selection signatures in worldwide Sheep populations. Compared to previous analyses, we make use of statistical methods that (i) take account of the hierarchical structure of sheep populations, (ii) make use of Linkage Disequilibrium information and (iii) focus specifically on either recent or older selection signatures. We show that this allows to pinpoint several new selection signatures in the sheep genome and to distinguish those related to modern breeding objectives and to earlier post-domestication constraints. The newly identified regions, together with the one previously identified, reveal the extensive genome response to selection on morphology, color and adaptation to new environments.