Genome-wide association study of body weight and conformation traits in neonatal sheep

Sheep, an important source of meat, dairy and fur, play an essential part in agricultural economy around the world. Body weight (BW) and body conformation traits are the key of sheep industry, however, the underlying distinction of genetic mechanisms were poorly attuned. In this study, genome-wide association studies (GWAS) were implemented to identify possible promising genes response for BW and body conformation traits in neonatal sheep using high throughput chip (630 K). After quality control, 277 individuals and 518 203 variants were analyzed by GEMMA software in a mixed linear model. A total of 48 genome-wide suggestive SNPs were obtained, 4, 4, 11 and 29 of which were separately associated with BW, withers height (WH), body length (BL) and chest girth (CG). In total, 39 genes associated with BW and body conformation traits were identified by aligning to the sheep genome Ovis aries_v4.0, and most of them were involved in cell cycle and body development. Specifically, we found some promising candidate genes, such as FOS like 2 or AP-1 transcription factor subunit (FOSL2) for BW, potassium voltage-gated channel subfamily D member 2 (KCND2) for WH, transmembrane protein 117 (TMEM117), transforming growth factor beta induced (TGFBI) and leukocyte cell derived chemotaxin 2 (LECT2) for BL, trafficking kinesin protein 1 (TRAK1) and LOC101102529 for CG. These results provide cues for similar studies aiming at uncovering the genetic mechanism underlying body development and marker-assisted selection program focusing on BW and body conformation traits in sheep.