Author(s): Ajao Kehinde, Idris Muyideen and Gbolagade Monsurat

Abstract: Patterns of homozygosity can be influenced by several factors, such as demography, re combination, and selection. Using the goat SNP50 Bead Chip, we genotyped 3171 goats belonging to 117 populations with a worldwide distribution. Our objectives were to characterize the number and length of runs of homozygosity (ROH) and to detect ROH hotspots in order to gain new insights into the consequences of neutral and selection processes on the genome-wide homozygosity patterns of goats. The proportion of the goat genome covered by ROH is, in general, less than 15% with an inverse relationship between ROH length and frequency i.e. short ROH (0.20) FROH values. For populations from Asia, the average number of ROH is smaller and their coverage is lower in goats from the Near East than in goats from Central Asia, which is consistent with the role of the Fertile Crescent as the primary center of goat domestication. We also observed that local breeds with small population sizes tend to have a larger fraction of the genome covered by ROH compared to breeds with tens or hundreds of thousands of individuals. Five regions on three goat chromosomes i.e. 11, 12 and 18, contain ROH hotspots that overlap with signatures of selection. Patterns of homozygosity (average number of ROH of 77 and genome coverage of 248 Mb; FROH<0.15) are similar in goats from different geographic areas. The increased homozygosity in local breeds is the consequence of their small population size and geographic isolation as well as funder effects and recent inbreeding. The existence of three ROH hotspot that co-localize with signatures of selection has also played an important role in increasing the homozygosity of specific regions in the goat breeds analysed in this work display low levels of homozygosity, which is favorable for their genetic management and viability.

Pages: 44-51 | Views: 351 | Downloads: 162

Download Full Article: Click Here