Abstract:

【Objective】 The objective of this study was to analyze the genetic differences of donkey growth hormone（GH）gene from its DNA, cDNA and deduced amino acid sequence in different species.【Method】The PCR primers were designed online according to result of gene homology comparison. Donkey GH gene DNA and cDNA sequence were cloned from liver tissue and blood by RT-PCR and PCR, and compared with GH gene sequences of different species by bioinformatics method. 【Result】 The donkey GH gene sequence was 1 928 bp, including the 706 bp cDNA sequence with the complete CDS. By comparison of DNA and cDNA sequences, it was found that the GH gene sequence included 5 exons and 4 introns, encoding 216 aa, including the signal protein of 26 aa and matured protein of 190 aa. Based on the analysis of the similarity of GH genes in different species on the level of cDNA, DNA and the deduced amino acid, there was the most homology to the horse. The GH gene of donkey was conservative in the process of evolution and its promotor was not specific TATA box, but CATA box. 【Conclusion】 DNA and cDNA sequences were obtained from liver tissue and blood, and the mutation of C→G DNA sequence in 1 267 may affect the growth and development of donkeys and horses. All researches made an essential foundation for GH regulation of gene expression, evolution, polymorphism analysis in the future.

Key words: donkey, growth hormone gene, cloning, sequence analysis