Mapping Data

Experiment

• Experiment
  TEXT-QTL
• Chromosome
  X
• Reference
  J:120855 Szumska D, et al., A novel locus on the X chromosome regulates post-maturity bone density changes in mice. Bone. 2007 Mar;40(3):758-66
• ID
  MGI:3710662

Genes

Gene	Assay Type
Sbmd5	visible phenotype
DXMit197	PCR amplified length variant
DXMit31	PCR amplified length variant

Notes

• Experiment
  Genetic loci associated with post-maturity spinal bone mineral density (BMD) were mapped in two independent between(AKR/J x SAMP6)F2 intercrosses.
  
  Two reciprocal crosses were set up between mouse strains AKR/J and SAMP6, pairing males of each strain individually with females of the other strain. The F1 hybrid progeny from each cross direction were randomly interbred, and their resulting progeny composed the independent F2 intercosses.
  
  The first cross consisted of 253 F2 animals and the second cross consisted of 110 F2 animals. Microsatellite markers at an average spacing of 7 cM were used for the genome scan. Parental strain AKR/J displays continued increase in spinal BMD up to 8 months of age whereas parental strain SAMP6 plateaus at 4 months of age.F2 animals were scanned for spinal and global BMD at 4, 6, and 8 months of age.
  
  Significant linkage to post-maturity spinal BMD (Sbmd5) was detected at 140 Mb - 155 Mb on mouse Chromosome X between DXMit197 and DXMit31. This locus explained 34% of the variance and reached LOD=5 in the larger F2 cross and LOD=5.8 in the smaller F2 cross. AKR/J-derived alleles at Sbmd5 confer increased post-maturity spinal BMD with and additive mode of inheritance. Sbmd5 is also shows suggestive linkage to global BMD. Interestingly, a locus on human Chromosome Xassociated with lumbar BMD in post-menopausal women maps near the 96% confidence interval of Sbmd5.
  
  SNP mapping of AKR/J and SAMP6 strains revealed several stretches of non-polymorphic DNA on mouse Chromosomes X outside the Sbmd5 region, and also onmouse Chromosome 7. Authors surmise these synonymous genetic regions did not arise by chance.
  
  Linkage to post-maturity spinal BMD was also detected on mouse Chromosome 7 with LOD=11.8 but only in the smaller F2 cross. This locus requires further verification.