Identification and characterization of single nucleotide polymorphisms in DMRT3 gene in Indian horse (Equus caballus) and donkey (Equus asinus) populations.

The research article explores the identification and analysis of single nucleotide polymorphisms (SNPs) in the DMRT3 gene in Indian horses and donkeys, which are related to equine abilities such as racing, riding, and gaitedness. The findings reveal the impact of this gene on genetic diversity among different breeds of horses and donkeys.

Methodology

• The researchers studied the DMRT3 gene by sequencing and characterizing it from 72 samples of Indian horses and 33 samples of Indian donkeys. It allowed them to identify and analyze novel polymorphisms or SNPs in this gene.
• They discovered an SNP (A>C) at the 878 position in the horses studied. For Indian donkey breeds, they found identical SNPs (A>C) at two different nucleotide positions, 878 and 942, in the DMRT3 gene, located on chromosome 23.

Mutations and Impact

• The research found that both horses and donkeys have a non-synonymous mutation (A>C) at nucleotide 878 (codon 61) that changes a Stop codon (TAG>TCG) to a coding codon Serine. This kind of mutation results in a different amino acid being incorporated into the protein, which can alter its function.
• In contrast, donkeys possess a synonymous mutation at nucleotide 942 (codon 82) that changes Serine (TCA>TCC) into Serine. Synonymous mutations do not alter protein sequences but can affect gene expression and function by other mechanisms.

Distribution and Genetic Diversity

• A phylogenetic tree was created to show the equal distribution of the DMRT3 gene among different equine breeds.
• Findings indicated high levels of genetic diversity in majority of donkey breeds. In contrast, horse breeds and Halari donkey displayed the least genetic diversity.

Application and Relevance

• The mutation in DMRT3 gene is reported to have a significant impact on gaitedness – the ability of a horse to move with a specific footfall pattern. The study found that the frequency of this mutation is high in gaited breeds and in horses bred for harness racing. This suggests the DMRT3 gene may play an essential part in defining the performance and racing capabilities of these horses.