Polymorphisms of MRF4 and H-FABP genes association with growth traits in Qinchuan cattle and related hybrids.

PCR–RFLP was applied to analyse polymorphisms within the MRF4 and heart fatty acid-binding protein (H-FABP) gene for correlation studies with growth traits in three-month-old Qinchuan (QQ), Qinchuan × Limousin (LQ) and Qinchuan × Red Angus (AQ) cattle. The results showed that 874 bp PCR products of MRF4 digested with XbaI and 2,075 bp PCR products of H-FABP digested with HaeIII were polymorphic in the three populations. Moreover, the frequencies of allele A at MRF4 locus and allele B at H-FABP locus in the QQ, AQ, and LQ populations were 0.8358/0.8888/0.8273 and 0.8358/0.7500/0.8195 respectively. Allele A at MRF4 locus and allele B at H-FABP locus were dominant in the three populations. No statistically significant differences in growth traits were observed among the genotypes of the all three populations at H-FABP locus. However, the association of MRF4 polymorphism with growth traits was then determined in all three populations. The body weight, withers height, heart girth and height at hip cross of individuals with genotype AA were higher than those with genotype AB or BB (P < 0.05). Therefore, we suggest that the MRF4 gene may function in the control or expression of growth traits, particularly body weight, withers height, heart girth and height at hip cross.