Exploring single nucleotide polymorphisms in GH, IGF-I, MC4R and DGAT1 genes as predictors for growth performance in dromedary camel using multiple linear regression analysis

Abstract

Understanding the genetic factors influencing the growth traits of animal is very important for an accurate selection and genetic improvement of these quantitative traits. Therefore, the aim of this study was to identify polymorphisms in growth hormone (GH), insulin-like growth factor-I (IGF-I), melanocortin-4 receptor (MC4R) and diacylglycerol O-acyltransferase 1 (DGAT1) genes and their association with body weight and daily gain in dromedary camels. Blood samples were collected from seventy camels using vacutainer tube containing EDTA as an anticoagulant for DNA extraction. PCR-DNA sequencing approach was performed to investigate polymorphisms in fragments for 5’ UTR of GH (286-bp) and part of coding sequence (CDS) of IGF-I (462-bp), MC4R (512-bp), and DGAT1 (390-bp) genes. Results revealed that there were single nucleotide polymorphisms (SNPs) in the investigated genes between the enrolled camels except for IGF-I gene that elicited a monomorphic pattern. The identified SNPs allocated camels into different groups according to which animal harbored the explored SNPs. Using multiple linear regression analysis (MLR), identified SNPs had a significant effect on body weight and weight gain at different age stages. Determination coefficients (R2) value indicated that variability in the phenotypic measurements of growth performance might be correlated with the identified SNPs in growth related genes. The area under the ROC curves was higher in the case of DGAT (0.793-1.0), followed by GH (0.736-0.866) and then MCR (0.410-0.545). DGAT anticipates body weight and weight gain traits better than GH and MCR. As a pilot study, single nucleotide polymorphisms in the investigated genes could be used as proxy predictors and genetic markers that permit a marker assisted selection for growth traits in dromedary camels.