Genetic Architecture of Mandible Shape in Mice: Effects of Quantitative Trait Loci Analyzed by Geometric Morphometrics

This study introduces a new multivariate approach for analyzing the effects of quantitative trait loci (QTL) on shape and demonstrates this method for the mouse mandible. We quantified size and shape with the methods of geometric morphometrics, based on Procrustes superimposition of five morphologic...

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Bibliographic Details
Published in:Genetics (Austin) 2001-02, Vol.157 (2), p.785-802
Main Authors: Klingenberg, Christian Peter, Leamy, Larry J, Routman, Eric J, Cheverud, James M
Format: Article
Language:English
Subjects:
Animals
Crosses, Genetic
Evolution
Evolution, Molecular
Genetic Variation
Genetics
Mandible - physiology
Mice
Mice, Knockout
Models, Anatomic
Multivariate Analysis
Phenotype
Quantitative Trait, Heritable
Rodents
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Summary:This study introduces a new multivariate approach for analyzing the effects of quantitative trait loci (QTL) on shape and demonstrates this method for the mouse mandible. We quantified size and shape with the methods of geometric morphometrics, based on Procrustes superimposition of five morphological landmarks recorded on each mandible. Interval mapping for F(2) mice originating from an intercross of the LG/J and SM/J inbred strains revealed 12 QTL for size, 25 QTL for shape, and 5 QTL for left-right asymmetry. Multivariate ordination of QTL effects by principal component analysis identified two recurrent features of shape variation, which involved the positions of the coronoid and angular processes relative to each other and to the rest of the mandible. These patterns are reminiscent of the knockout phenotypes of a number of genes involved in mandible development, although only a few of these are possible candidates for QTL in our study. The variation of shape effects among the QTL showed no evidence of clustering into distinct groups, as would be expected from theories of morphological integration. Further, for most QTL, additive and dominance effects on shape were markedly different, implying overdominance for specific features of shape. We conclude that geometric morphometrics offers a promising new approach to address problems at the interface of evolutionary and developmental genetics.
ISSN:0016-6731
1943-2631
1943-2631
DOI:10.1093/genetics/157.2.785