Mapping Data

Experiment

• Experiment
  TEXT-Meta Analysis
• Chromosome
  12
• Reference
  J:69668 Turri MG, et al., QTL analysis identifies multiple behavioral dimensions in ethological tests of anxiety in laboratory mice. Curr Biol. 2001 May 15;11(10):725-34
• ID
  MGI:2148626

Genes

Gene	Assay Type
Axtrb2	visible phenotype
Axtofd10	visible phenotype

Notes

• Reference
  DeFries strains:
  QTL were mapped in two large F2 intercrosses from four lines derived from a replicated selection experiment for open-field activity, an animal model for susceptibility to anxiety. The foundation for the selection experiment consisted of an F3 generation derived from a cross between inbred lines, BALBc/J and C57BL/6J. Ten F3 litters that contained at least two males and females were chosen at random. The most active male and female within each litter were selected to become the progenitors of one selected line, termed H1. The least active male and female from each of the same ten litters were selected to serve as progenitors of a low activity line, L1. The same selection procedure was applied to members of a second randomly chosen group of 10 F3 litters as parents for replicate selected lines H2 and L2. The resulting progeny represented the first selected generation. Within the two high lines the most active male and female were selected from each litter, whereas the least active male and female were selected from each litter in the two low lines.Thirty generations of selection were completed and in generation 30 open field activity scores of the high lines were 30 times greater than those of the low lines.
  Following the suspension of selection the lines were randomly mated within line for 18 generations and then inbred using brother-sister mating.
  
• Experiment
  A large set of ethological measures of anxiety-related behaviors were analyzed to explore the relationship between the behavioral phenotype and genotype of anxiety. Phenotypic and genotypic data from a total of 1636 mice from two intercosses of (H1 x L1)F2 and (H2 x L2) F2 DeFries strains decribed in a separate paper (J:70479) were obtained.
  
  Five behavorial tests were conducted in the open field arena, the elevated plus maze, the square maze, the light dark box and the mirror chamber. The test results from the two crosses were highly consistent and to maximize power and mapping resoultion the data was combined from both crosses in the current companion study. Likely QTL positions were determined using MAPMAKER-QTL and QTL-CARTOGRAPHER.
  
  The results of this study mapped 3 major QTL influencing anxiety-related behaviors on Chromosomes 1, 4 an 15. Other anxiety-related behavioral QTLs with multiple effects mapped to Chromosomes 7, 12, 14, 18 and X.
  
  Axtrb2, anxiety-related behavior 2 mapped to Chromosome 12.
  
  The combined LOD scores from both crosses, for each significant test measurement contributing to Axtrb2 follow:
  anxiety-related behavior 2, open field, total activity, LOD=3.6;
  anxiety-related behavior 2, light dark box, dark box activity, LOD=5.5; and
  anxiety-related behavior 2, light dark box, transitions, LOD=4.3.
  
  At each locus the direction of effect of the allele was examined from the less active strains, L1 and L2. Significant traits measured at Axtrb2 were decreased by the influence of the L1 or L2 allele. [Table 2].
  
  Table 3 gives the mapping results for loci influencing defecation in each test apparatus. Differentiation of defecation scores by components of the test apparatus were not possible. However results were consistent for each apparatus.
  
  QTL Axtofd10, anxiety-open field defecation 10, open field, day 2, mapped to Chromosome 12 with a combined LOD=3.21 at 34 cM. The L1 or L2 allele at this locus increased defecation.