Effect of melanocortin-4 receptor (MC4R) gene polymorphisms on growth characteristics and its possible use in selection of karacabey merino lambs

The study was carried out to determine the polymorphism of the Melanocortın-4 Receptor (Mc4R) gene and the effect of Mc4R genotypes on the growth traits of Karacabey Merino lambs. Animal material of study consisted of 300 head of Karacabey Merino lambs raised in the Sheep Breeding Research Instutıte Bandirma, Balikesir, Turkey. Birth weight, live weight at 45, 90, and 180th days of age, average daily gains between birth to 90. days of age, birth to 180. days of age, 90. to 180. days of age, body measurements, and ultrasound measurements at 90. and 180. days of age were recorded for all lambs to determine the variation in Mc4R genotypes. The Mc4R gene was divided into two regions as 825 and 590 bp (Mc4R1 nad Mc4R2 respectively) using specifically designed primers. 9.T>C, 12.G>C, 93.G>A and 381.G>A SNP's were detected in the Mc4R1 region. 681.G>C and 1016.G>A SNP's were identified in the Mc4R2 region. The polymorphism at nucleotide position 9.T>C was identified to be significantly associated with rump width at 90 days of age (p<0.05). 12.G>C was related to live weight at 90 days of age (p<0.05) and average daily gain (0-90) (p<0.05). There was a statistically significant relationship between 93.G>A SNP and rump width at 90 days of age (p<0.05). 381.G>A was significantly associated with backfat thickness at 90 days of age (p<0.01). The variation at position 681.G>C was related to withers height, cannon circumference (p<0.05), and backfat thickness at 90 days of age (p<0.01). The 1016.G>A was determined to be associated with live weight at 180 days of age (p<0.05), average daily gain (0-90, 0-180) (p<0.05), skin thickness at 90 days of age (p<0.05) and muscle depth at 180 days of age (p<0.05). It was concluded that the Mc4R gene could be used as molecular markers for growth traits in sheep.