Phylogenetic Relationships and Functional Enrichment Analysis of the Nuclear-Encoded Twinkle Helicase (TWNK) Gene In Sheep (Ovis aries) and Related Artiodactyla Species

Abstract

 The nuclear-encoded Twinkle Helicase (TWNK) gene is unique in the sense that it has its own inheritance pattern which is maternal. The study was undertaken to help understand the phylogenetic relationship between sheep (Ovis aries) and the next 14 closely related species based on the nuclear-encoded TWNK gene. The Ovis aries TWNK helicase gene sequence (accession XM_004020117.5) was retrieved from NCBI and analyzed using BLAST to identify homologous sequences across related Artiodactyla species. The homologous sequences were transferred via the alignment command of MEGA into the software for nucleotide and protein alignments. Phylogenetic analyses were carried out using both the NCBI BLAST tool and MEGA. Functional enrichment analysis of the reference gene was done using STRING. Phylogenetic analysis using MEGA-X revealed that Ovis canadensis (99.50% identity), Caprocormis sumatraensis (98.15% identity), and Capra hircus (98.38% identity) showed the highest sequence similarity to Ovis aries, while Monodon monoceros (Narwhal, 86.24% identity) served as an outlier. The neighbour-joining phylogenetic tree demonstrated clear evolutionary relationships among the ruminant species, with distinct clades representing Caprinae and Bovinae subfamilies. Functional enrichment analysis using STRING identified ten genes that are closely associated with the TWNK helicase gene, including MRPS12, ERAL1, and POLRMT, all involved in mitochondrial transcription, ribosome biogenesis, and RNA metabolism. This integrative approach combining sequence alignment, phylogenetic reconstruction, and functional pathway analysis provided insights into the evolutionary conservation and molecular function of the nuclear-encoded TWNK helicase gene across ruminant species, with potential applications in breed authentication and conservation genetics.