Two co‐inherited novel SNPs in the MC4R gene related to live body weight and hormonal assays in Awassi and Arabi sheep breeds of Iraq

• Published in: Veterinary medicine and science 2021-05, Vol.7 (3), p.897-907
• Main Authors: Al‐Thuwaini, Tahreer M., Al‐Shuhaib, Mohammed Baqur S., Lepretre, Frederic, Dawud, Halla Hassan
• Format: Article
• Language: English
• Subjects: Animals; Association analysis; Bioassays; Body weight; Conformation; Energy balance; Gene loci; Gene polymorphism; Genetic diversity; Genetic markers; genetic polymorphism; Genotyping; haplotype; Haplotypes; Homeostasis; Hormones; in silico; Laboratories; Life Sciences; Linkage disequilibrium; Melanocortin; Melanocortin MC4 receptors; Missense mutation; Nucleotide sequence; Original; Polymerase chain reaction; Polymorphism; production trait; Sheep; Single-nucleotide polymorphism; Testosterone
• ISSN: 2053-1095; 2053-1095
• DOI: 10.1002/vms3.421

Melanocortin‐4 receptor (MC4R) gene plays a key role in the regulation of body weight and energy homeostasis. This study aims to evaluate the association of single nucleotide polymorphisms (SNPs) of the MC4R gene with live body weight and hormonal assays in two breeds of sheep that differ in productive performance, Awassi and Arabi. All known coding sequences of the MC4R gene were covered in this study. DNA samples from 150 animals (Awassi and Arabi breed) were genotyped by PCR‐single‐strand conformation polymorphism (PCR‐SSCP) to assess their pattern of genetic variation. Concerning exon 1, clear heterogeneity was detected with three different SSCP‐banding patterns. The sequencing reactions confirmed these variations by detecting the presence of the two novel SNPs, 107G/C and 138A/C, and three genotypes, GC, AC and AA. The 107G/C SNP was detected in GC genotype, while the 138A/C was detected on both GC and AC genotypes. The other SSCP‐banding pattern (AA genotype) did not show any detectable unique variation. Both SNPs were closely and strongly linked in both breeds (D' and r2 values were 1.00), which signifies that both loci were co‐inherited as one unit. Association analysis indicated that both breeds with GC/AC haplotype showed higher live body weight (37.250 ± 0.790) relative to the GG/AA (30.244 ± 0.968) and CC/CC (47.231 ± 1.230) haplotypes (p  .05) with the measured traits. In conclusion, the two novel SNPs (107G/C and 138 A/C) were highly associated with live body weight in both breeds. Haplotype analysis confirmed that these two novel SNPs were in strong linkage disequilibrium (LD) and could be used as genetic markers for sheep phenotypic trait improvement. MC4R gene effect on the regulation of live body weight and hormonal assays in Awassi and Arabi sheep. The sequencing reactions confirmed the presence of the two novels SNP 107G/C and 138A/C in exon 1 of MC4R gene. The two novel SNP (107G/C and 138 A/C) were highly associated with live body weight. GC/AC haplotype showed higher live body weight relative to the GG/AA and CC/CC haplotypes. Haplotype analysis confirmed that these two novel SNP were in strong linkage disequilibrium and could be used as genetic markers for sheep phenotypic traits improvement.