Tissue expression,association analysis between three novel SNPs of the RXRαgene and growth traits in Chinese indigenous cattle

Retinoid X receptor(RXR) α is a member of the nuclear hormone receptor superfamily that mediates the biological effects on several hormones,vitamins,and regulates lipid,glucose and energy metabolism.In this study,the tissue expression profiles of the bovine RXRαgene and association analysis of single nucleotide polymorphisms(SNPs) with growth traits were carried out in 413 Chinese native cattle.The expression profile was analysed in ten Jiaxian cattle tissues by real-time PCR,and the results showed that RXRαgene was abundantly expressed in adipose tissue and spleen,moderately expressed in heart,liver,lung,kidney,muscle and testis.Meanwhile,three SNPs(T27919A,T28139C and G28142A) and five haplotypes were identified.Haplotype with TTG was dominant with frequency of 69.1%.Chi-square test showed all populations were in Hardy-Weinberg equilibrium(P>0.05) at the three sites except Jiaxian cattle at G28142A site and Qinchuan cattle at T27919A site.Statistical analysis of combined sites showed that the individuals with TTGA genotype had significantly higher heart girth than those with TAGG genotype(P<0.05) and the animals with AAGA genotype had higher body weight than those with TAGG genotype(P<0.05) in T27919A-G28142A site.Heart girth,abdominal circumference and body weight of individuals with TCAG genotype were exceedingly higher than those with TTGG(P<0.01),TTGA and TCGG(P<0.05) in T28139C-G28142A site.For T27919A-T28139C site,the individuals of TCTA and TCTT genotype had significantly higher heart girth and lower height at hip cross than those with TTTA(P<0.05),and the body weight of TCAA and TCTT genotype individuals was higher than those with TTTA(P<0.05).In conclusion,these results provided evidence that the polymorphisms of RXRαgene were associated with growth traits and might apply to Chinese indigenous yellow cattle breeding program as a possible candidate for marker-assisted selection(MAS).