GHRL gene-based genotyping of ovine and caprine breeds reveals highly polymorphic intronic sequences in Awassi sheep with several RNA motifs

BACKGROUND: The current study was conducted to identify the genetic polymorphism of ghrelin (GHRL) gene of sheep and goats, as well as to determine whether these polymorphisms were associated with the evolutionary genetic differences in the involved species. This study was performed on 233 sheep and 91 goats. Two genetic loci of 113 bp and 262 bp partially spanning over exon 2/intron 2 and intron 4/exon 5 of GHRL gene respectively were amplified and genotyped using polymerase chain reaction–single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing methods. RESULTS: The SSCP banding pattern of 262-bp locus indicated the presence of four diplotypes (BC, BB, AC, and AB) in Awassi sheep, three diplotypes (BC, BB, and AB) in Karadi sheep, and only two diplotypes (BC and BB) in all goats’ samples. The current study detected several novel SNPs in the ovine–caprine populations as well as two SNPs that are observed only in sheep, including intron4:119 C>A and intron4:123 T>G. The phylogenetic analysis revealed that the observed diplotypes resided within ovine sequences and were closely related to caprine counterparts. Computational analyses indicated the presence of various intronic RNA motifs. However, all these motifs were gathered in Awassi breed. CONCLUSION: It is stated that the intron 4 is highly diverse amongst goats and sheep as well as within sheep with a particular emphasis on Awassi. This genetic peculiarity may in turn suggest a high polymorphic pattern of this breed in comparison with other related counterparts.