Genetic mapping of quantitative trait loci for resistance to Haemonchus contortus in sheep

Marshall, K., Maddox, J. F., Lee, S. H., Zhang, Y., Kahn, L., Graser, H. -U., Gondro, C., Walkden-Brown, S. W. and van der Werf, J. H. J. (2009) Genetic mapping of quantitative trait loci for resistance to Haemonchus contortus in sheep. Animal Genetics, 40 3: 262-272. doi:10.1111/j.1365-2052.2008.01836.x

Author Marshall, K.
Maddox, J. F.
Lee, S. H.
Zhang, Y.
Kahn, L.
Graser, H. -U.
Gondro, C.
Walkden-Brown, S. W.
van der Werf, J. H. J.
Title Genetic mapping of quantitative trait loci for resistance to Haemonchus contortus in sheep
Journal name Animal Genetics   Check publisher's open access policy
ISSN 0268-9146
Publication date 2009-06
Sub-type Article (original research)
DOI 10.1111/j.1365-2052.2008.01836.x
Volume 40
Issue 3
Start page 262
End page 272
Total pages 11
Place of publication Oxford, United Kingdom
Publisher Wiley-Blackwell
Language eng
Formatted abstract
This paper presents results from a mapping experiment to detect quantitative trait loci (QTL) for resistance to Haemonchus contortus infestation in merino sheep. The primary trait analysed was faecal worm egg count in response to artificial challenge at 6 months of age. In the first stage of the experiment, whole genome linkage analysis was used for broad-scale mapping. The animal resource used was a designed flock comprising 571 individuals from four half-sib families. The average marker spacing was about 20 cM. For the primary trait, 11 QTL (as chromosomal/family combinations) were significant at the 5% chromosome-wide level, with allelic substitution effects of between 0.19 and 0.38 phenotypic standard deviation units. In general, these QTL did not have a significant effect on faecal worm egg count recorded at 13 months of age. In the second stage of the experiment, three promising regions (located on chromosomes 1, 3 and 4) were fine-mapped. This involved typing more closely spaced markers on individuals from the designed flock as well as an additional 495 individuals selected from a related population with a deeper pedigree. Analysis was performed using a linkage disequilibrium-linkage approach, under additive, dominant and multiple QTL models. Of these, the multiple QTL model resulted in the most refined QTL positions, with resolutions of <10 cM achieved for two regions. Because of the moderate size of effect of the QTL, and the apparent age and/or immune status specificity of the QTL, it is suggested that a panel of QTL will be required for significant genetic gains to be achieved within industry via marker-assisted selection.
Keyword Disease resistance
Genome scan
Haemonchus contortus
Linkage analysis
Linkage disequilibrium-linkage analysis
Quantitative trait loci
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Non-UQ

Document type: Journal Article
Sub-type: Article (original research)
Collection: Queensland Brain Institute Publications
Version Filter Type
Citation counts: TR Web of Science Citation Count  Cited 34 times in Thomson Reuters Web of Science Article | Citations
Scopus Citation Count Cited 37 times in Scopus Article | Citations
Google Scholar Search Google Scholar
Created: Wed, 29 Aug 2012, 14:24:08 EST by System User on behalf of Queensland Brain Institute