Meeting Abstract

LBS2.4  Thursday, Jan. 3  Of �mice� and mammals: Using classical inbred mice to study the genetic architecture of masticatory performance. VINYARD, C.J.*; PAYSEUR, B.A.; NEOUCOM; University of Wisconsin, Madison cvinyard@neoucom.edu

Comparative mammalian morphologists maintain a long-standing interest in the evolution of mammalian jaw form and function. While numerous studies examine jaw functional morphology, few have investigated the genetic architecture of performance abilities in the mammalian masticatory apparatus because of inadequate samples and/or technology. We use a biomedical mouse model to quantify maximum jaw-opening ability, or gape, across 21 strains of inbred mice to 1) measure heritable variation in gape among strains, 2) correlate gape and jaw form, and 3) search for genomic regions underlying variation in gape. We measured maximum jaw opening as the distance between the upper and lower incisors with the jaw opened as widely as possible in 417 mice (9-12 weeks of age) from 21 strains (typically 10 males and females per strain). ANCOVA indicates significant differences in gape among strains (covariate=age) for both sexes (p<0.001). Partial correlations relative to body mass^0.333 suggest that maximum gape shares slight, yet significant, associations with jaw length in males (p<<0.05) and condyle length (estimating radius of curvature) (p<0.05) in both sexes. Thus, relatively longer jaws and/or condyles likely facilitate increased jaw gapes as predicted by simple mechanical models. Intra-class correlations reveal significant genetic variation in gape among strains. We compare strain phenotypes to publicly available SNPs to nominate genomic regions that may influence maximum jaw opening. Our results illustrate the potential for harnessing the prodigious biomedical research efforts focused on classical inbred mouse strains for modeling the genetic architecture of masticatory performance in mammals. Supported by the Jackson Laboratory and Mouse Phenome Database.