Genomic analysis of gastrointestinal parasite resistance in Akkaraman sheep

Authors: ARZIK, YUNUS - Erciyes University; KIZILASLAN, MEHMET - Erciyes University; WHITE, STEPHEN - Former ARS Employee; Piel, Lindsay; CINAR, MEHMET - Erciyes University

Submitted to: Genes
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/19/2022
Publication Date: 11/22/2022
Citation: Arzik, Y., Kizilaslan, M., White, S.N., Piel, L.M., Cinar, M.U. 2022. Genomic analysis of gastrointestinal parasite resistance in Akkaraman sheep. Genes. 13(12). Article 2177. https://doi.org/10.3390/genes13122177.
DOI: https://doi.org/10.3390/genes13122177

Interpretive Summary: Economic productivity of small ruminants is negatively impacted following animal infection with gastrointestinal parasites. Infection can cause outcomes such as weight loss, anemia, and, if disease is severe, animal death. Problematically, gastrointestinal parasites are persisting within the environment for longer periods of time, presumably due to climate change, and many of these parasites are gaining resistance to antiparasitic drugs. Nonetheless, there is the possibility that some small ruminants have inherited mechanisms to maintain a higher resistance against gastrointestinal parasites. Therefore, the referenced study completed heritability estimates and a genome wide association study to assess whether certain Akkaraman sheep, a common domestic breed present in Turkey's agricultural community, maintained higher resistance to infection with gastrointestinal parasites and if resistance could be associated with specific genes or genetic regions. It was determined that Akkaraman sheep inherit resistance traits at a low to moderate level. Further, there were 12 genes that could be associated with an altered burden of intestinal parasites. These associated genes are responsible for cellular events such as cell signaling, cell death, and immune functions. Future investigation into these genes may define animals which are able to thrive even in the presence of gastrointestinal parasites, making these animals especially valuable in the ever increasing climate of parasite resistance to present interventions/drugs.

Technical Abstract: Abstract: Genome-wide association studies (GWAS) have been used as an effective tool to understand the genetics of complex health traits such as gastrointestinal parasite (GIP) resistance with the advancement of genotyping technologies. The aim of this study was understanding genetics of gastrointestinal parasite (nematodes, Moniezia spp., Eimeria spp.) resistance in Akkaraman sheep by performing genomic heritability estimations and conducting GWAS to uncover genomic regions responsible for GIP resistance. The samples from 475 animals were genotyped using the Axiom 50K Ovine Genotyping Array. Genomic heritability estimates ranged from 0.00 to 0.34 for parasite resistance traits. Indicating that measured phenotypes have a low to moderate heritability estimates. A total of 2 genome- and 10 chromosome-wide significant SNPs for parasite resistance traits were detected as a result of GWAS. Accordingly, NELL1, TENM3, ST6GALNAC3, ATRNL1, HIPK1, SYT1, ALK, ZNF596, TMCO5A, PTH2R, LARGE1 and SCG2 genes were suggested as candidates for parasite resistance traits. The majority of these candidate genes were involved in several basic biological processes that are essential and important for immune system functions and cellular growth; specifically inflammatory responses, cellular transport, cell apoptosis, cell differentiation, histone de-acetylation and endocytosis. These results have implications on animal breeding program studies due to the effect that the genetic background has on parasite resistance, which underlies many productive, health and wellness related traits.