Experiment
Composite interval mapping (CIM) was used for localization of QTL involved in modulating response to infection with Borrelia burgdorferi. Parental strains C3H/HeN and C3H/HeJ are susceptible to B.burgdorferi-induced arthritis whereas parental strains C57BL/6N and BALB/cAnN are resistant. Four different backcrosses and the reanalysis of a previous intercross were performed.
In the (C57BL/6N X C3H/HeN)F1 X C57BL/6N backcross a novel QTL, Bbaa13 was identified on
on Chr 4. Bbaa13 was linked to ankle swelling at 6.5 cM with marker D4Mit264, LRT=18.6 accounting for 10.7% of variance. [Table 2.]
In the reanalysis of the (C57BL/6N X C3H/HeN)F2 intercross another novel, Chr 4 QTL, Bbaa23, was identified. Bbaa23 is linked to the number of B.burgdorferi in heart tissue post-infection. It mapped to 49.6 cM with marker D4Mit219, LRT=21.6 accounting for 11.2% of variation. [Table 2.]
The reanalysis of the (C57BL/6N X C3H/HeN)F2 intercross also confirmed the previoulsy identified Bbaa1 QTL on Chr 4. Using CIM Bbaa1, linked to ankle swelling, mapped to 28.6 cM with marker D4Mit139, LRT=19.6. [Table 3.]
C3H/HeN-derived alleles are associated with increased arthritis susceptibility and severity at all QTL mapped in this experiment.
Analysis Tools