GENOTYPING OF GROWTH PERFORMANCE GENES IN SOME LOCAL SHEEP BREEDS

Abstract

Sherif Awad Aziz Melak: Genotyping of Growth Performance Genes in Some Local Sheep Breeds, Unpublished PhD of Agriculture Sciences Thesis, Department of Animal Production, Faculty of Agriculture, Ain Shams University, 2019. This study aimed to investigate possibilities of utilizing both quantitative and molecular genetics tools for genetic improvement of growth performance in Egyptian Barki and Rahmani sheep. Estimate genetic parameters of body weights using random regression model as one of quantitative genetic tools was the first objective of this study. The second objective was discovering and genotyping some single nucleotide polymorphism (SNP) as a method of molecular genetics. In addition, to study some non-genetic factors affecting sheep body weights. Records of 3,205 and 13,215 Egyptian Barki and Rahmani lambs were collected from Borg Al-Arab and El-Serw experimental farms belonged to Animal Production Research Institute, respectively. Data were collected from 1984 to 2017 for Barki and from 1972 to 2017 for Rahmani lambs. Data were utilized to estimate (co)variance components and genetic parameters for body weights from birth up to 480 days by the average information REMLF90 (AIREMLF90) software using random regression model with Legendre polynomials (LP). Also, the effects of gender, type of birth, season of birth, year of birth, age of dam at lambing and some of the interactions between those effects on body weights were studied. Nine candidate SNPs were selected according to individual-based on coefficient of genetic variation (Fst values) and the genes that have possible association with growth harboring those SNPs of previous study on Barki lambs. A total of 47 Barki and 40 Rahmani lambs, born in the period from 2013 till 2015 in two generations were utilized to genotype single nucleotide polymorphism. Genomic DNA was extracted from