Genetic analysis of skull shape variation and morphological integration in the mouse using interspecific recombinant congenic strains between C57BL/6 and mice of the mus spretus species.
To assess the genetic basis of the skull shape variation and morphological integration in mice, we have used a tool based on the cross between the distantly related mouse species Mus spretus (SEG/Pas strain) and the laboratory strain C57BL/6 called interspecific recombinant congenic strains (IRCSs). The genome of each IRCS consists on average of 1.3% of SEG/Pas derived sequences, located on multiple chromosomes as small-sized, DNA segments. Quantitative trait loci (QTL) on the skull shape, separated into dorsal and ventral sides, were analyzed in 17 IRCSs by a Procrustes superimposition method using 3D landmarks. The shapes of 16 strains differed significantly from C57BL/6. Discrepancy in the QTLs effects was found between the dorsal side and the anterior region of the ventral side due to a differential effect of the SEG/Pas alleles on the skull shape. A comprehensive analysis of all allelic combinations of the BCG-66H strain showed strong epistatic interactions between SEG/Pas segment acting on both skull sides. Epistatic pleiotropy and covariation between sides were dependent in SEG/Pas alleles direction and contributed to the strong morphological integration between sides. Introduction of Mus spretus alleles in a C57BL/6 background induced strong morphological changes mostly in SEG/Pas alleles direction and provided evidence for high level of morphological integration.
Burgio
Gaëtan
G
Unité postulante de Génétique fonctionnelle de la Souris, CNRS URA 2578, Institut Pasteur, 75724 Paris cedex 15, France. grburgio@utas.edu.au
Baylac
Michel
M
Heyer
Evelyne
E
Montagutelli
Xavier
X
D000818:Animals; D002508:Cephalometry; D006824:Hybridization, Genetic; D051379:Mice; D008810:Mice, Inbred C57BL; D040641:Quantitative Trait Loci; D011995:Recombination, Genetic; D012886:Skull / Q000033:anatomy & histology*