MOLECULAR GENETIC VARIATION (POLYMORPHISMS) USING IN-SILICO METHODS IN DETERMINING EFFECT OF GDF8 GENE IN CATTLE, SHEEP AND GOATS

Abstract

The in-silico research was carried out to explore the effect of molecular genetic variation of the myostatin (GDF8) gene in cattle, sheep, and goats. A total of twenty-three (23) GDF8 gene nucleotide sequences comprising cattle (4), sheep (8) and goats (11) were retrieved from NCBI, aligned, translated, and compared using ClustalW. The variation in sequence length base pairs (bp) of the GDF8-gene within and among species ranged between 381 bp and 7831 bp. The functional analysis of mutations using SIFT showed that ten amino acid substitutions (S7Y, M14T, N26K, L43M, F139Y, F94L, R48G, A167S, S125T, and P285E) in cattle, seven in sheep (F7Y, L16I, K36E, L43M, N48T, K49T, and T120S), and ten in goats (F7Y, F14I, L16I, H23Y, K36E, K39Q, T42A, L43M, N48T, and L53I) were beneficial. However, three in cattle (Y9C, E46D, and R161T), five in sheep (Y9C, E34G, R45G, T114A, and I119V) and six in goats (V26L, W27R, G37R, T40I, R50G, and G57R) were harmful. The significant value (p<0.01) for the relative ratio of non-synonymous substitutions per non-synonymous site (dN) to the number of synonymous mutations per synonymous site (dS) known as omega (ɷ = dN/dS), revealed positive selection for all the studied species (1.55 for cattle, 2.71 for sheep and 1.87 for goats). The Tajima’s D indicates selective sweep in sheep (-2.39). The phylogenetic trees showed a close relationship among members of the Bovidae family. It can be inferred from the study that cattle, sheep, and goat GDF8 genes are polymorphic genes with numerous mutations being more beneficial. Further research should be conducted to explore the potential applications of these results in selecting desirable traits and the genetic improvement of cattle, sheep, and goats.