Mapping Data

Experiment

• Experiment
  TEXT-Congenic
• Chromosome
  1
• Reference
  J:187304 Burgio G, et al., Nasal bone shape is under complex epistatic genetic control in mouse interspecific recombinant congenic strains. PLoS One. 2012;7(5):e37721
• ID
  MGI:5811841

Genes

Gene
Nabq1

Notes

• Experiment
  To study genetic determinism of variations in the shape of the mouse nasal bone a set of 55 interspecific recombinant congenic stains (IRCS) were generated between C57BL/6J (B6) and the Mus spretus derived SEG/Pas (SEG) mice. Macroscopic comparison of SEG and B6 mice revealed marked differences in the shape of the nasal bone; the B6 giving to a rectangular shape and the SEG a trapezoidal outline. Genotyping revealed that each strain in the collection inherited on average 1.3% of its genome from SEG, under the form of a few chromosomal segments with an average size of 13 Mb.
  
  Among the IRCS strains examined, BcG66H/Pas stood out with features intermediate between the two parental strains. To identify which of the three SEG derived chromosomal regions present in BcG66H/Pas were responsible for the nose shape difference, 91 (BcG66H x C57BL/6J)F2 male mice were analyzed. For QTL mapping the nasal bone shapes were submitted to outline analysis, considering 3 main parameters. Single marker ANOVA revealed highly significant association with genotype at:
  
  Nabq1, nasal bone morphology QTL 1, mapped to Chr 1, with a peak at marker D1Mit306 with a LOD score of 1.99.
  
  Nabq2, nasal bone morphology QTL 2, mapped to Chr 18, with a peak at marker D18Mit123 with a LOD score of 3.18 (a significant threshold of 5%=1.89).
  
  For both markers the SEG allele was associated with a decreased phenotypic value and heterozygotes were intermediate between B6/B6 and SEG/SEG homozygotes, suggesting codominant effect. Phenotypic values of F2 mice decreased almost linearly with the total number of SEG alleles carried at D1Mit306 and D18Mit123 suggesting that the two loci act additively.
  
  Next each of the SEG derived chromosomal regions present in BcG66H was introduced by two backcrosses into a congenic strain respectively designated as
  B6.SEG-(D1Mit81-rs6259837),
  B6.SEG-(D13Mit106-D13Mit290) and
  B6.SEG-(D18Mit23-D18Mit123).
  
  Twenty five to 33 mice per congenic strain were analyzed. Variations in bone width in the rostral and caudal regions, resulting in rectangular vs trapezoid nose outlines were consistent with previous observations. The results confirmed the individual effects of Nabq1 on Chr 1 and Nabq2 on Chr 18.
  
  To explore interactions between QTL bicongenic strains were created by crossing pairs of congenic strains. Data revealed that the SEG derived regions present in BcG66H strain influence the shape of the nasal bone either independently or in combination.
  
  Although B6.SEG-(D13Mit106-D13Mit290) mice by themselves did not show any effect on nasal bone shape in comparison to B6, it was able to partially abolish the effect of Nabq1.