Polymorphism analysis on the second intron of the GH gene in chinese donkeys

To reveal the genetical diversity of different donkey breeds at molecular level and provid some bases for the breed resource evaluation and utilization of donkeys in China, polymorphism of the second intron of the GH gene was analysised by PCR-SSCP in the seven donkey breeds (LX, GZ, XJ, GL, FIB, DZ, IN), The results showed three haplotypes with the percentage of 1.7% in 174 samples were obtained, the haplotype diversity was high as 0.678 and 0.542 for the Linxian and Huaibei donkey and low as 0.077 for Xingiiang donkey with that of 0.409 and 0.462 for Guangling donkey and Guanzhong donkey, respectively with that of 0.355 and 0.304 for Dezhou donkeys and finnan donkeys, respectively. The amplified fragments of A and B haplotypes were cloned and sequenced. The result showed the fragments of B haplotypes had one substitution mutation at 735 site (G -> C), the fragments of A haplotypes had one substitution mutation at 869 site (G -> T). The results confirmed that there were polymorphisms in the second intron (214 bp) of donkey GH gene for the first time.