Genetic Characterization, Polymorphism and Evolution Analysis in Part of the EDNRB Gene in Cattle and Goat

The aim of this study was to analyze the polymorphisms existing in the 5´ flanking region, exonic, and some parts of the intronic regions as well as methylation analysis of the EDNRB gene in cattle and goat. These regions were sequenced in three different breeds of cattle including Sistani, Golpayegani, and Holstein and were compared with that of Marghoz goat. The results identified that this gene encodes 441 amino acid residues in cattle and goat with highly conserved domains between them. A total of 55 transition and 43 transversion mutations were observed in the 5´ and 3´ flanking and exonic regions. Among the six coding mutations in goat EDNRB gene, a missense mutation of C236>T resulted in substitution of Alanine-79 to Valine. The frequency of the T allele in the goat population was 0.77. In addition, an insertion of TG(29) repeat was identified at the -773 upstream of the gene in goat samples. The promoter region of the gene harbors two GC rich conserved motifs and transcription factor binding sites for GATA and SP1 in both species, which may modulate the expression of the gene. The methylation analysis of a 182 bp fragment of the 5´ region of the EDNRB gene, located at the fringe of the CpG island, was found to be completely methylated in both cattle and goat. Evolutionary analysis revealed that the cattle and goat EDNRB proteins were sisters in their own clade and dN / dS ratio demonstrated that the EDNRB gene underwent purifying selection during evolution.