Caracterización de los patrones de homocigosidad de once razas ovinas españolas

The demographic changes that have occurred in domestic animal populations, whether due to natural causes or to management practices, can lead to an increase in homozygosity and inbreeding. The aim of the present work was to evaluate the homozygosity levels of eleven Spanish sheep breeds as well as to study their genetic relationships with other European and African sheep populations. For this, the genotypic information of 551 sheep from Spain (Castellana, Canaria de Pelo, Churra, Latxa, Gallega, Ojalada, Ripollesa, Rasa Aragonesa, Roja Mallorquina, Segureña and Xisqueta), Europe (Altamurana, Comisana and Swiss White Alpine) and North Africa (Barki and Algerian breeds) genotyped with the Ovine SNP50 Bead Chip of Illumina has been used. In this way, it has been shown that ten of the Spanish breeds under analysis are closely related to non-Spanish European breeds, while the Canarian Hair breed shows a close relationship with African breeds. On the other hand, low levels of homozygosity were found in the 11 Spanish breeds i.e. the number and length of the ROH (A total of 8,179 ROH were identified in sheep, from which 93.65 per cent measured less than 15 Mb), as well as the values of the FROH (An average 0.043 among all breeds) were, in general, very low. In the different ovine breeds under analysis, ROH hotspots were found in the chromosomes Oar3 (87-89 Mb, 151-158 Mb and 188-202 Mb), Oar6 (38-40 Mb, 77 Mb and 92-97 Mb) and Oar8 (12 Mb, 29 Mb and 32-35 Mb), but a low positional coincidence was observed with ROH hotspots detected in other studies as well as with ROH hotspots detected in goats. Despite this, a ROH hotspot was consistently detected in sheep and goats and it contained genes associated with body growth (NCAPGLCORL). In conclusion, the low levels of homozygosity and inbreeding detected in the 11 Spanish ovine breeds under study offer a positive perspective on their genetic conservation, since we do not foresee that inbreeding depression could reduce their viability and reproductive potential