International Mammalian Genome Society

The 14th International Mouse Genome Conference (2000)

Table of Contents * Genes, Physical Mapping and Sequencing * Gene Identification * Bioinformatics * Common Resources * RIKEN Session * Functional Genomics * Complex Traits * Mutagenesis * Developmental Genetics and Differentiation * Verne Chapman Memorial Lecture I and II

G8. Marker-Assisted Introgression Experiment in Mice

Delphin O. Koudandé¹, Johan A.M. van Arendonk¹ and Fuad Iraqi^2
1Wageningen Institute of Animal Sciences, Wageningen University, Wageningen, The Netherlands;
²International Livestock Research Institute, Nairobi, Kenya.

African trypanosomiasis is an endemic disease affecting sixty million cattle in 37 African countries, and annual direct and indirect losses are estimated at more than US$5 billion. Most West African Bos taurus breeds are genetically resistant to trypanosomiasis and chromosomal localization of cattle trypanotolerance quantitative trait loci (QTL) is underway. In an earlier experiment, using F₂ and F₆ crosses of a susceptible (A/J) and resistant (C57BL/6) mouse strains, 3 trypanotolerance QTL were mapped to chromosomes 1, 5 and 17. A marker-assisted introgression experiment involving the two inbred lines has been set up to study the effectiveness of an introgression program. The experiment started in 1997 with reciprocal crossing of the two parental lines producing an F₁ followed by four generations of backcrossing to the susceptible strain, an intercrossing phase and a multiplication phase. During backcross and intercross, animals were selected based on markers flanking the identified QTL (5, 18 and 7 cM on chromosomes 1, 5 and 17 respectively). Ten groups of animals carrying different combinations of marker-genotypes were produced. These groups and the two parental lines were challenged with Trypanosoma congolense and trypanotolerance was measured as the survival time following infection over a period of 22 weeks. Difference in survival time between the two parental lines was 58 days.