Screen of small fragment mutations within the sheep thyroid stimulating hormone receptor gene associated with litter size

Abstract

The thyroid stimulating hormone receptor (<i>TSHR</i>), a glycoprotein hormone receptor, plays an important role in metabolic regulation and photoperiod control in the time of reproduction in birds and mammals. Previous genome-wide association studies revealed that the <i>TSHR</i> gene was related to reproduction and its function was identified in female reproduction, but rare studies reported the polymorphism of <i>TSHR</i> gene. However, the molecular mutations of the <i>TSHR</i> gene in sheep have not been reported so far. Herein, we explored potential polymorphisms of the sheep <i>TSHR</i> gene, and a 29 bp nucleotide sequence variant (rs1089565492) was identified in the AUW sheep. There were three genotypes of the 29 bp variant locus detected which named 'II' 'DD' and 'ID' been identified. Association analysis results showed the 29 bp variant was significantly associated with the litter size of the AUW sheep (<i>p</i> < 0.05). This finding suggests that the 29 bp nucleotide sequence variant within <i>TSHR</i> gene could be a candidate marker of reproduction traits for sheep breeding improving through the marker-assisted selection (MAS).