Identifying and exploiting the molecular basis of resistance to gastrointestinal parasites (PhD)


The overall goal of this project was to identify candidate genes associated with resistance that could be used as selection markers for future breeding programmes. Using an experimentally-infected Blackface lamb model, genes with characterised immune response functions in mice were investigated in sheep. This confirmed that these genes have robust associations with disease outcome in worm-infected lambs.
Current genetic techniques (such as SNP chips) use predominantly predicted mutations from cattle to interrogate the ovine genome for disease-associated genes. The genes, and mutations with them, discovered in this project, are real ovine mutations and represent novel markers that could be used  in updated genetic techniques for the genetic selection of worm-resistant sheep in the future.
Beef & Lamb
Project code:
01 October 2012 - 30 September 2016
AHDB Beef & Lamb, BBSRC, Sheep Improved Genetics Ltd
AHDB sector cost:
Total project value:
Project leader:
Roslin Institute, University of Edinburgh


About this project

The Challenge

Teladorsagia circumcincta or Brown Stomach worm is the most common species of nematode parasite that infects sheep in the UK. The worm causes an estimated £84 million per annum in production loss to UK farmers, through loss of appetite and growth impairment in young stock. Animals are treated regularly with anthelmintic (wormer) throughout spring and summer to reduce the worm burden. However, the overuse of these drugs has led to the evolution of drug-resistant parasites which are extremely difficult to kill. This has led to research into other ways to manage the infection, with the aim to limit the development of drug resistance whist maintaining flock health.

Sheep naturally acquire immunity to the worms with repeated exposure to small numbers of the parasite. This immunity is also heritable, so stock can be bred to naturally develop resistance to the parasite.

The Project

The aims of this project are to:

  1. understand how sheep respond to worm infection
  2. understand and identify genes associated with the response, and
  3. to identify variation within those genes which may contribute to resistance

This will be achieved through the analysis of resistant and susceptible sheep genotypes, which will highlight the differential expression of genes in resistant and susceptible animals. It is hoped that this work will uncover genes that can be used for selective breeding of stock in the future. 


Hazel Wilkie