Extensive diversity of the ADRB3 gene in Chinese sheep identified by PCR-SSCP

The beta(3)-adrenergic receptor (ADRB3) is the main mediator of the lipolytic and thermogenic effects of high catecholamine concentrations. Polymorphism in the ovine ADRB3 gene has been reported to be associated with birth weight, growth rate, carcass composition, and cold survival. Eight alleles have been identified in New Zealand sheep, but to date, breeds from other countries have not been studied in detail. In this study, we employed PCR-SSCP to detect ADRB3 polymorphism in the Hu, Tan, small-tailed Han, and Tibet breeds of Chinese sheep. Thirteen SSCP patterns were observed, including the eight previously reported and five new patterns. The newly identified SSCP patterns represent five novel sequences, increasing the reported number of alleles of ADRB3 from 8 to 13. In these Chinese sheep, the most common allele was the previously reported allele C (49.0%); the A allele was the next most common (22.0%). These results suggest that Chinese sheep have more diversity in ADRB3 than New Zealand sheep and therefore have possibly been selected either naturally or via breeding for different traits.