Association study reveals Th17, Treg and Th2 loci related to resistance to Haemonchus contortus in Florida Native sheep

Project Type: Graduate Student
Funds awarded in 2017: $16,500.00
Projected End Date: 08/31/2019
Grant Recipient: University of Florida
Region: Southern
State: Florida
Major Professor:
Raluca Mateescu
University of Florida
The aim of this study was to identify for the first time single nucleotide polymorphisms (SNPs) associated with H. contortus resistance in Florida Native sheep, using a targeted sequencing approach. One hundred and fifty three lambs were evaluated in this study. At the start of the trial, phenotypic records for fecal egg count (FEC), FAMACHA score, body condition score (BCS), and weight were recorded and deworming of sheep with levamisole (18 mg per kg of body weight) was performed. Ten days post-deworming (baseline) and 28 days post baseline, a full hematogram of each sheep was obtained and FEC, FAMACHA score, BCS and weight were assessed. Average daily gain was calculated at the end of the trial. Out of 153 animals, 100 sheep were selected for genotyping using a targeted sequencing approach. Targeted sequencing panel included 100 candidate genes for immune response against H. contortus. SNPs were discarded if call rate < 95% and minor allele frequency ≤0.05. A mixed model was used to analyze the response variables and included the identity by state matrix to control for population structure. A contemporary group (age, group and sex) was included as fixed effect. Bonferroni correction was used to control for multiple testing. Eighteen SNPs on chromosomes 1, 2, 3, 4, 6, 7, 11, 15, 18, 20, 24 and 26 were significant for different traits. Our results suggest that loci related to Th17, Treg and Th2 responses play an important role in the expression of resistant phenotypes. Several genes including ITGA4, MUC15, TLR3, PCDH7, CFI, CXCL10, TNF, CCL26, STAT3, GPX2, IL2RB and STAT6 were identified as potential markers for resistance to natural H. contortus exposure. This is the first study that evaluates potential genetic markers for H. contortus resistance in Florida Native sheep.
Zaira M. Estrada Reyes, University of Florida
Owen Rae, University of Florida
Carol Postley, Fairmeadows farm
Myriam B. Jimenez Medrano, University of Florida
Joel Leal Gutierrez, University of Florida
Raluca Mateesucu, University of Florida
Target audiences:
Farmers/Ranchers; Researchers
Ordering info:
Zaira M. Estrada Reyes
University of Florida
Gainesville, FL 32611
Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.