The research proposed here will investigate the quantitativegenetic basis of brain and body size variation in randombredlaboratory mice. The magnitudes and correlations of two kinds ofgenetic differences will be examined: those caused by anindividual's own genes, and those caused by its mother's genes,through the prenatal and postnatal environments that she providesfor her offspring. These will be assessed by examining therelationship between observed and theoretical similarities amongrelatives. Knowledge of these components could help resolvedifferences between current models of evolution of brain and bodysize, and maternal genetic variance may play a key role in life.history evolution. Also, measurements of these and other traitsfor many mammals will be used to determine evolutionary patternsat different taxonomic levels, and relate these to differences inprenatal, postnatal and other components of growth that might beinfluenced by direct and maternal genetic effects. Geneticevolutionary mechanisms that can produce these patterns will bemodeled. The results will provide new information about the relativeimportance of maternal genetic differences to growth of offspringbrain and body sizes. Also, the research addresses thefundamental biological relationship between genetic differences(maternal and offspring), individual growth, and evolutionarychange. Other areas that depend upon knowledge of genetic andenvironmental influences on growth, such as animal improvement,might also benefit from the basic research proposed here.
