5 research outputs found
A report to FAO on âThe design, execution and analysis of livestock breed surveys â a case study in Zimbabwe.
Confirmation and dissection of QTL controlling resistance to malaria in mice
We developed an Fââ AIL population from an Fâ cross of A/J (susceptible) and C57BL/6J (resistant) mouse strains. One thousand Fââ mice were challenged with P.c. 'chabaudi' 54X, and 340 mice selected from the phenotypic extremes for susceptibility and resistance were genotyped for microsatellite markers on Chromosomes (Chrs) 5, 8, and 17. QTL originally detected in backcross and Fâ populations were confirmed on the three chromosomes within narrower genomic regions, by maximum likelihood and regression analyses. Each of the previously mapped QTL on Chrs 5 and 17 resolved into two linked QTLs. The distal and proximal QTLs on Chrs 5 and 17, respectively, map to the previously reported QTL
High resolution mapping of chromosomal regions controlling resistance to gastrointestinal nematode infections in an advanced intercross line of mice
Fine mapping of quantitative trait loci (QTL) associated with resistance to the gastrointestinal parasite Heligmosomoides polygyrus was achieved on Fâ/Fâ offspring (1076 mice) from resistant (SWR) and susceptible (CBA) mouse strains by selective genotyping (top and bottom 20% selected on total worm count in week 6). Fecal egg counts were recorded at weeks 2, 4, and 6, and the average was also analyzed. Blood packed cell volume in weeks 3 and 6 and five immunological traits (mucosal mast cell protease 1, granuloma score, IgG1 against adult worm, IgG1, and IgE to L4 antigen) were also recorded. On Chromosome 1 single-trait analyses identified a QTL with effects on eight traits located at about 24 cM on the Fâ mouse genome database (MGD) linkage map, with a 95% confidence interval (CI) of 20-32 cM established from a multitrait analysis. On Chromosome 17 a QTL with effects on nine traits was located at about 18 cM on the MGD map (CI 17.9-18.4 cM). Strong candidate genes for the QTL position on Chromosome 1 include genes known to be involved in regulating immune responses and on Chromosome 17 genes within the MHC, notably the Class II molecules and tumor necrosis factor