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) x C57BL/6N backcross authors state that previoulsy identified QTL Bbaa2 and Bbaa6, on Chrs 5 and 12 respectively, were reproduced.
[10.28.2015 Curator Note: Because Bbaa2 and Bbaa6 were originally mapped in J:52017 in 1999 using an (C3H/HeNCr x C57BL/6NCr)F2 intercross which differs from the backcross population used here, we consider the current study aseparate mapping experiment and have named the Chr 5 QTL Bbaa24 and the Chr 12 QTL Bbaa27.]
On Chr 12 Bbaa27 is linked to tendon sheath mapping from 45-46 cM between markers D12Mit194 and D12Mit121 with an LRT=34.1 accounting for 18.9% of the variance. The same QTL is also linked to total IgG from 46-52 cM mapping between D12Mit121 and D12Mit139 with an LRT=28.8 accounting for 11.3% of the variance. [Table 2.]
C3H/HeN-derived alleles are associated withincreased arthritis susceptibility and severity at all QTL mapped in this experiment.
In the (C57BL/6N X C3H/HeN)F1 X C3H/HeN backcross a novel QTL, Bbaa10, also mapped to Chr 12. Bbaa10 was linked to both tendon sheath, from 16-28 cM between markers D12Mit46 and D12Mit69 LRT=20.1 accounting for 9.6% of variance, and total IgG mapping to 28 cM with marker D12Mit69, LRT=11.9 accounting for 5.2% of trait variance. [Table 2.]
The reanalysis of the (C57BL/6N X C3H/HeN)F2 intercross also confirmed the previously identified Bbaa6 QTL on Chr 12. Using CIM Bbaa6 linked to both total IgG (LRT=29.5) and total IgM (LRT=27.6), at 52.0 cM with marker D12Mit139,[Table 3.]
C3H/HeN-derived alleles are associated with increased arthritis susceptibility and severity at all QTL mapped in this experiment.
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