Extreme-QTL mapping of monepantel resistance in Haemonchus contortus.

Background: Haemonchus contortus, a gastrointestinal nematode parasite of sheep, is mainly controlled by anthelmintics; the occurrence of anthelmintic resistance leads to treatment failures and increases economic burden. Because molecular mechanisms involved in drug resistance can be elucidated by genomic studies, an extreme quantitative trait locus (X-QTL) mapping approach was used to identify co-segregation of the resistance phenotype with genetic markers to detect the genome-wide variants associated with monepantel resistance in H. contortus.

PCR-based genotyping of SNP markers in sheep.

Single nucleotide polymorphisms (SNPs) are the main type of variation in genome, enabling them to be associated with traits of economic importance in livestock. Genome-wide association studies (GWAS) have led to the discovery of SNPs associated with desirable traits in sheep. However, in these studies, SNPs are genotyped by high-throughput methods in genome scale, which are expensive and require sophisticated equipment and analysis methods.