Applying genomics towards the development of breeding programs for resistance to tripanosomosis in small ruminants: an overview of the Resistrypsheep project in Angola

Abstract

In Angola, almost 70% of the population is dependent on agriculture as a source of income, and local breeds are strongly linked to the economy and culture of local populations. Due to the occurrence of several social and environmental disasters in Angola, along with the increasing demand for livestock products, many of the local breeds are at risk of extinction. The characterization and conservation of these breeds is of upmost importance since local farmers rely mostly on local breeds that play an important role as a source of protein for human nutrition and of other products such as leather and wool. Moreover, local breeds appear to be adapted to several environmental stressors Advances in next-generation sequencing of DNA have allowed for easy generation of whole genome-sequencing data that allows the identification of reliable candidates genes or genomic regions under selection without requiring pedigree information. This work aims to characterize the genetic diversity of Angolan local sheeps and identify selection signatures related to trypanosomiasis resistance. Genetic diversity will be assessed using panels of 60K SNP (single nucleotide polymorphism) markers in samples from 30 sheeps. The identification of selection signatures will be based on the sequencing of 10 genomes, utilizing complementary approaches to pinpoint candidate genes associated with resistance to trypanosomiasis. A total of 68 blood samples were collected from sheeps in the provinces of Cunene, Namibe, Malanje and Cabinda to support the study of genetic diversity and the identification of selection signatures. For the identification of signatures of selection, so far six samples were sequenced, yielding read lengths of 78.95, 104.04 and 74.36, 81.31, 112.04 and 59.47 Gb, with a coverage of 30X; and two samples yielding read lengths 26.18 and 41.68 Gb with a coverage of 10X. The preliminary analysis of this data will be presented comparing the analyzed genomes with other sheep breeds available in public repositories.