GWAS and inbreeding depression on body size traits in Qira black sheep (Ovis aries)

Qira black sheep is a famous indigenous sheep
breed in China. The objectives of this study are to identify candidate genes
related to body size, and to estimate the level of inbreeding depression on
body size based on ROH in Qira black sheep. Here, 188 adult Qira black
sheep were
genotyped with a high density (630 K) SNP chip and GWAS for body weight (BW) and body
size traits (including withers height, body slanting length, tail length (TL),
chest girth (CG), chest width (CW), and chest depth (CD)) were performed using an additive
linear model. In consequence, 12 genome- and chromosome-wide significant SNPs
and, accordingly, six candidate genes involved in muscle
differentiation, metabolism
and cell processes were identified. Of them, ZNF704 (zinc
finger protein 704) was identified for BW, AK2 (adenylate kinase 2) and
PARK2 (parkin RBR E3 ubiquitin protein ligase) for TL, MOCOS
(molybdenum cofactor sulfurase) and ELP2 (elongator
acetyltransferase complex subunit 2) for CW, and MFAP1
(microfibril associated protein 1) for CG. Additionally, inbreeding depressions
on body size were observed in the current herd. These results will provide insightful
understandings into the genetic mechanisms of adult body size, and into the conservation and utilization of Qira black sheep.