Association of in the Gene with Litter Size are Inconsistent among Chinese Indigenous Pigs and Western Commercial Pigs.

Eastern and Southern Chinese pigs have been imported to Western countries to improve economic traits including fertility in Western pig breeds by intensive selecting Chinese advantage genes. It was reported that the selected Asian-derived non-synonymous mutations including (G > T) in the aryl hydrocarbon receptor () gene could increase litter size in multiple European commercial lines. The objective of this study is to identify whether in the gene is polymorphic and has an influence on the litter size in 10 pig populations including five Chinese indigenous breeds, one cultivated breed, one lean-type breed, two North American lean-type breeds, and one European lean-type breed. We found that had polymorphism in all 10 populations, whereas was associated with litter size only in French Yorkshire (FRA-Y) and Chinese cultivated Suhuai (SH) pigs containing approximately 75% British Yorkshire pigs ancestry. Our results indicated that in the gene was a potential marker to improve litter size in European commercial lines and the pigs containing ancestries of European commercial lines, whereas this locus maybe not a causal mutation affecting the litter size but only in linkage disequilibrium with the causal mutation for litter size.