Please use this identifier to cite or link to this item: https://hdl.handle.net/1959.11/22103
Title: Identification of Novel Loci Associated with Gastrointestinal Parasite Resistance in a Red Maasai x Dorper Backcross Population
Contributor(s): Benavides, Magda Vieira (author); Sonstegard, Tad S (author); Kemp, Stephen (author); Mugambi, John M (author); Gibson, John  (author); Baker, Robert Leyden (author); Hanotte, Olivier (author); Marshall, Karen (author); Van Tassell, Curtis (author)
Publication Date: 2015
Open Access: Yes
DOI: 10.1371/journal.pone.0122797Open Access Link
Handle Link: https://hdl.handle.net/1959.11/22103
Abstract: Gastrointestinal (GI) parasitic infection is the main health constraint for small ruminant production, causing loss of weight and/or death. Red Maasai sheep have adapted to a tropical environment where extreme parasite exposure is a constant, especially with highly pathogenic Haemonchus contortus. This breed has been reported to be resistant to gastrointestinal parasite infection, hence it is considered an invaluable resource to study associations between host genetics and resistance. The aim of this study was to identify polymorphisms strongly associated with host resistance in a double backcross population derived from Red Maasai and Dorper sheep using a SNP-based GWAS analysis. The animals that were genotyped represented the most resistant and susceptible individuals based on the tails of phenotypic distribution (10% each) for average faecal egg counts (AVFEC). AVFEC, packed cell volume (AVPCV), and live weight (AVLWT) were adjusted for fixed effects and co-variables, and an association analysis was run using EMMAX. Revised significance levels were calculated using 100,000 permutation tests. The top five significant SNP markers with - log10 p-values >3.794 were observed on five different chromosomes for AVFEC, and BLUPPf90/PostGSf90 results confirmed EMMAX significant regions for this trait. One of these regions included a cluster of significant SNP on chromosome (Chr) 6 not in linkage disequilibrium to each other. This genomic location contains annotated genes involved in cytokine signalling, haemostasis and mucus biosynthesis. Only one association detected on Chr 7 was significant for both AVPCV and AVLWT. The results generated here reveal candidate immune variants for genes involved in differential response to infection and provide additional SNP marker information that has potential to aid selection of resistance to gastrointestinal parasites in sheep of a similar genetic background to the double backcross population.
Publication Type: Journal Article
Source of Publication: PLoS One, 10(4), p. 1-20
Publisher: Public Library of Science (PLoS)
Place of Publication: United States of America
ISSN: 1932-6203
Field of Research (FOR): 060307 Host-Parasite Interactions
060406 Genetic Immunology
070203 Animal Management
Socio-Economic Outcome Codes: 970106 Expanding Knowledge in the Biological Sciences
970107 Expanding Knowledge in the Agricultural and Veterinary Sciences
Peer Reviewed: Yes
HERDC Category Description: C1 Refereed Article in a Scholarly Journal
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