Mapping Data

Experiment

• Experiment
  TEXT-QTL
• Chromosome
  4
• Reference
  J:84715 Zhang S, et al., Genetic contributions to body weight in mice: relationship of exploratory behavior to weight. Obes Res. 2003 Jul;11(7):828-38
• ID
  MGI:2681288

Genes

Gene	Assay Type
Bw8q2	visible phenotype
D4Mit68	PCR amplified length variant
Htr6	reported elsewhere
Htr1d	reported elsewhere
Hmgcl	reported elsewhere
Sdc3	reported elsewhere

Notes

• Experiment
  Linkage analysis was performed on 514 (C57BL/6J x A/J)F2 animals and on 223 (C57BL/6J x A/J)F1 x A/J backcross animals to identify QTLs associated with body weight and exploratory behavior. 102 microsatellite markers at an average spacing of 14 cM were used in the genome scan. Parental strain A/J exhibits lower activity levels but is resistant to obesity whereas parental strain C57BL/6J exhibits higher activity levels but is susceptible to obesity. More specifically, C57BL/6J males exhibit increased weight compared to A/J males while A/J females exhibit increased weight compared to C57BL/6J females. All animals were place on a regular 6% fat diet and weighed at 8 and 10 weeks of age.
  
  A QTL named Bw8q1 was identified in the (C57BL/6J x A/J)F2 cross and mapped to distal mouse Chromosome 1 at 100 cM with LOD=4.4 at D1Mit116. This QTL is associated with body weight at 8 and 10 weeks of age and spans 77 cM - 102 cM. Homozygosity for C57BL/6J-derived alleles confer increased activity and decreased body weightcompared to animals homozygous for A/J-derived alleles at Bw8q1. Several previously identified QTLs associated with weight and exploratory behavior overlap with Bw8q1 such as Emo1 and Exq3 (see reference for full description.)
  
  A second QTL named Bw8q2 was identified in the (C57BL/6J x A/J)F1 x A/J backcross and mapped to 66 cM on mouse Chromosome 4 with LOD=3.3 at D4Mit68. Bw8q2 is significantly linked to body weight at 8 weeks of age, and is suggestively linked to body weight at 10 weeks of age. Heterozygous male animals exhibit increased body weight compared to male animals homozygous for A/J-derived alleles at Bw8q2. Potential candidate genes mapping near Bw8q2 include the serotonin receptors Htr6 and Htr1d, Hmgcl, and Sdc3.
  
  Suggestive linkages to weight gain were detected on proximal mouse Chromosome 4 (female-specific) at 12 cM near D4Mit53 (LOD=2.9), and on mouse Chromosome 6 at 24 cM near D6Mit74 (LOD=2.5).