Sequence Variation and Polymorphism Analysis of the Myostatin (MSTN) Gene in Indigenous Donkeys

Myostatin (MSTN), known as growth differentiation factor 8 (GDF-8) is a member of the transforming growth factor superfamily. MSTN inhibits skeletal muscle development and growth. Myostatin related variations are extremely important for the regulation of skeletal muscle mass and apoptosis. However, polymorphism of MSTN gene is scanty in donkeys.

We sampled thirty-six donkeys, consisting of Halari, Spiti, Ladakhi and Indian-French (Poitou) genotypes and extracted genomic DNA from blood. PCR amplification and Sanger sequencing of the MSTN gene. Sequence analysis and SNP detection were done with UGENE software, followed by haplotype analysis. The phylogenetic relationships among the different breeds were determined using Maximum Likelihood method in MEGA X software.

First time, we analyzed the single nucleotide polymorphisms (SNPs) of the MSTN gene in four Indian donkey breeds. In this study, two novel SNPs (T>C) at nucleotide positions 2396 (codon12) and 2398 (codon13) and one SNP (G>A) at position 2422 (codon 21) were identified in the second exon of the MSTN gene. From these two SNPs (T>C), one is a non-synonymous mutation the second is a synonymous mutation and the third (G>A) is a non-synonymous mutation. Two haplotypes (H1–H2) were analyzed, haplotype (H2) was the most dominant in all breeds. Ladakhi donkey represented the highest haplotype diversity. Maximum Likelihood Tree: The Ladakhi donkey breed is more genetically related to the horse and donkey reference; Similar to the donkey reference sequence, Halari donkey is also closely related. The sequences of the MSTN gene were submitted to the NCBI GenBank with Accession numbers OQ436746-and OQ447192-OQ447217. Finally, the MSTN gene and its SNPs require further studies, at protein and molecular level, in association with morphological traits which influence the economic traits of Indian donkey breeds.