ARS | Publication request: TOWARDS IDENTIFICATION OF THE GENETIC CONTROL OF RESISTANCE TO GASTROINTESTINAL HELMINTH INFECTIONS IN SHEEP AND MICE.

Submitted to: Meeting Abstract
Publication Type: Abstract
Publication Acceptance Date: August 10, 2005
Publication Date: September 20, 2005
Citation: Iraqi, F.A., Mugambi, J.M., Sonstegard, T.S., Garcia, F.J., Van Tassell, C.P., Hanotte, O., Nagda, S., Wakelin, D., Gibson, J.P., Behnke, J.M., Baker, L.R. 2005. Towards identification of the genetic control of resistance to gastrointestinal helminth infections in sheep and mice. Fourth All African Conference on Animal Agriculture. Tanzania, Abstract 45.

Technical Abstract: Mapping of Quantitative Trait Loci (QTL) for indicators of GI nematodes infection in East African Red Maasai sheep is the first step towards positional cloning of the genes underlying resistance to parasitism. Double backcross population in six families were generated from crosses of Red Maasai and Dorper (susceptible) sheep. Faecal egg count and blood packed red cell volume were monitored through two cycles of natural challenge on pasture, followed by one artificial challenge with Haemonchus contortus under controlled indoor conditions. A total worm count was determined at the end of each cohort experiment. Genome-wide search for QTL associated with resistance to the infections is ongoing. In parallel to the sheep study, we have also been studying the genetic control of helminth resistance in mice. A total of 14 QTL on 12 different chromosomes affecting both parasitological and immunological traits were mapped in a F2 (SWR x CBA) population, and subsequently fine mapped to a smaller genomic interval using advanced intercross lines (AIL) approach.