Mssq6 interacts with Mssq18 on chromosome 14.
Mapping and Phenotype information for this QTL, its variants and associated markers
Genetic loci affecting mandible size and shape were mapped using 190 mice from a (C57BL/6JJcl x KK-A<y>/TaJcl)F2 intercross. Of the F2 population, 97 animals had the A<y>/a genotype and 93 animals had the a/a genotype. Thirteen measurements taken from the right mandible and 3 principal components were assessed in experimental animals 6-7 months of age. Parental strain KK-A<y>/TaJcl displays increased values across most of the 13 mandible measurements compared to parental strain C57BL/6JJcl. The A<y> allele increases mandible size in KK animals compared to the a allele. A panel of 100 polymorphic markers was used for linkage analysis.
Mssq6 (mandible size and shape QTL 6) mapped to the central part of mouse Chromosome 5 near D5Mit267 (24 cM), D5Mit113 (42 cM) and D5Mit239 (58 cM) in the a/a F2 group, A<y>/a F2 group and combined F2 group (highest LOD=7.8). Mssq6 is linked to 3 mandible measurements and principal component 3. KK-derived alleles at Mssq6 confer increased values for three mandible size measurements. However, C57BL/6JJcl-derived alleles at Mssq6 confer increased values for principal component 3. Msx1 at 21 cM is a possible candidate gene for Mssq6. An interacting locus was detected at 10 cM on mouse Chromosome 14 near D14Mit44 and is named Mssq18 (mandible size and shape QTL 18). Homozygous C57BL/6JJcl-derived alleles at Mssq6 in conjunction with homozygous KK- or C57BL/6JJcl-derived alleles at Mssq18 confer decreased mandible size. Heterozygosity at both Mssq6 and Mssq18 significantly increases mandible size. This interaction is statistically significant (LOD=3.7).
The distal portion of chromosome 5 is linked to four mandible measurements and principal component 1 near D5Mit161 (70 cM, highest LOD=7.3). This locus, Mssq7 (mandible size and shape QTL 7), is present in the a/a F2 group and combined F2 group. KK-derived alleles at Mssq7 confer increased mandible size. An interacting locus named Mssq17 (mandible size and shape QTL 17) was identified at 25.5 cM on chromosome 10 near D10Mit184. Heterozygous alleles at Mssq7 in conjunction with homozygous C57BL/6JJcl-derived alleles at Mssq17 confer significantly increased mandible size. This interaction is statistically significant with LOD=4.8. Potential candidate genes for Mssq7 include Idua (57 cM) and Pds5b.