The association analysis between Cytb polymorphism and growth traits in three Chinese donkey breeds

The aim of this study was to investigate the effects of haplotypes in Cytb (Cytochrome b) gene on growth traits in three Chinese donkey breeds, Yunnan donkey (YN), Dezhou donkey (DZ) and Liangzhou donkey (U). The samples were genotyped for the Cytb gene by single strand conformation polymorphism (SSCP), and association analysis was conducted with growth traits. The results show that in most cases the effects of the gene on growth traits were not significant and that for the three different donkey breeds, the effects of the gene are different. For YN donkeys, there was a significant effect of the gene on the rump width (P<0.05) and the effect of genotype AA was larger than that of BB genotype (1.6 cm and 5.4% of the trait mean in YN donkeys. P<0.05). For DZ donkeys, the effect of gene on body height was significant (P<0.05). The results also verify that the SSCPs are caused by two cytosine to thymine and one guanine to adenine transitions, corresponding to amino acid substitutions of leucine for proline (L <-> P) and isoleucine for valine (I <-> V). (C) 2009 Elsevier B.V. All rights reserved.