Allelic polymorphism identified and analysis on the fifth exon of Chinese indigenous donkey GH gene by PCR-SSCP

Growth of animal is largely regulated by Growth Hormone (GH). In this study the objective was to investigate variations in the fifth exon of GH gene and their polymorphism in 5 Chinese indigenous donkeys by PCR-SSCP and DNA Sequencing Methods. The results showed that there was a transversion at nucleotide position 1802 of GH gene in the 5th exon named as GH-exon5-G1802C which led to a conservative Lysine to Asparagine substitution at amino acid position 205. In detail, two different alleles, A and B were identified and three genotypes were observed, AA, AB and BB with the frequency distribution of allele B from 0.5962-0.7344 in analyzed populations. The genetic diversity analysis revealed that all PIC values were between 0.3140 and 0.3656, implying that this locus within GH gene possessed moderate genetic diversity in 5 Chinese indigenous donkeys. The chi(2)-test showed that GZ donkey was significant deviation, DZ donkey was no significant deviation from Hardy-Weinberg equilibrium, GL, TN and XJ donkey was not in agreement Hardy-Weinberg equilibrium. The results confirmed that there were polymorphisms in the exon 5 of GH gene.