Insertion/deletion (InDel) variations in sheep PLAG1 gene locating in growth-related major QTL are associated with adult body weight and morphometric traits

Pleiomorphic adenoma gene 1 (PLAG1), locating in growth-related QTNs, was identified significantly affecting the body size of bovine, pig and mouse, while, the relationship between its genetic variation and ovine body size is still unknown. Here, two insertion/deletion (indel) loci of ovine PLAG1, including P1-del30bp and P5-del45bp, were investigated in 774 sheep from five breeds. The minor allele frequencies (MAF) of above indels were ranged from 0.093 to 0.276. The frequency of genotype DD in P1-del30bp site was significantly higher than others. As for P5-del45bp, the frequency of II genotype was higher than others. Moreover, the polymorphism information content (PIC) values of P1-del30bp and P5-del45bp was from 0.284 to 0.320 and 0.154 to 0.318 in these ovine breeds, respectively, which reflect relative high genetic diversity in sheep PLAG1. By Linkage disequilibrium (LD) test, the two indels were in strong linkage disequilibrium in D’ value, while the result of r2 test was opposite. The correlation analysis results showed that these indels of PLAG1 were significantly associated with 13 body morphometric traits especially body weight (P < 0.05). At P1-del30bp locus, it had higher significant correlation with chest width in LFTS ewe and cannon circumference index in Hu ewe (P < 0.01). At P5-del45bp locus, the cannon circumference in Lanzhou fat-tail sheep ewe, hip height of Tong ram and chest depth of Tan ram were higher significant (P < 0.01). These results demonstrated that the indel variants of sheep PLAG1 had associated with the body weight and morphometric traits of adult sheep, and these loci can be considered as molecular markers for sheep breeding.