Estimation of genomic inbreeding coefficient, detection of ROH Islands and Related Genes in different Egyptian sheep breeds adapted to different environment

In this study in order to estimate inbreeding coefficient and identify the ROH Islands associated with the genes under selection, the 50k BeadChip genotyped data of 206 sheep from 3 different Egyptian breeds were used. After quality control, 48361 SNPs in 204 sheep were remained for the future analysis. Inbreeding coefficient was calculated using four methods including, genomic relationship matrix (FGRM), excess of homozygosity (FHOM), correlation between uniting gametes (FUNI) using the GCTA 1.0 software and run of homozygosity (FROH) using the PLINK 1.9 software. One percent of SNP with the highest frequency in ROH were considered as ROH Islands. The lowest rate of inbreeding according to (FGRM, FHOM, and FUNI) was related to Wahati and the highest was related to Saidi breed. The highest amount of FROH (0.043) was observed in Saidi and the lowest amount (0.018) was observed in Barki breed. Average length of ROH ranged from 45.02 to 205.87 Mb, while the average number of ROH ranged from 8.14 to 14.07. The highest number ROH was observed on chromosome 2, while the lowest was on chromosome 26. Average inbreeding coefficient from FROH in Barki, Saidi and Wahati were estimated 0.018, 0.043 and 0.027 respectively. A total of 62 ROH Islands with length: 24.60 Kb to 13 Mb were identified, which covering less than 1% of the sheep genome. The ROH Islands was not distributed across the genome uniform and varied among breeds, but some common were identified. Bioinformatics analysis demonstrated that some of these genomic regions overlapped with reported genes that directly or indirectly influenced traits for adaptation and immune system (SEMA3D, CSF2, ITPR1), development of the skeletal muscle (UGGT1, ITGA2), and reproduction (ABHD16B). The results of this study revealed that, the selection processes in different sheep breeds for economic traits during several years, has led to the formation of many ROH islands in sheep genome, therefore scanning these regions at the genome level can be an alternative strategy to identify genes and associated loci with economic traits.