Most of the observable traits of plants and animals are affected by many genetic factors. The theory for the inheritance of such traits is known as quantitative genetics. For the past 60 years, animal and plant breeders have used quantitative genetics to improve domestic animals and crop species. In the past 20 years, quantitative genetics has swept into evolutionary biology and is revolutionizing our understanding of evolutionary processes and the genealogy of living species (phylogenetics). In applying quantitative genetic theory on an evolutionary time scale, one needs to assume that the system of inheritance remains unchanged. To make a strong test for constancy of inheritance, one needs good estimates of the inheritance systems for multiple populations which, in turn, have known evolutionary relationships. These requirements are difficult to meet and so strong tests for constancy of inheritance have not yet been conducted. The current project is a proposal for such a strong test using natural populations of garter snakes and water snakes. The strength of the proposal rests on the facts that: (1) large numbers of families can be sampled in each population to give good estimates of inheritance, (2) multiple populations and species can be sampled and (3) the phylogenetic relationships of the populations and species have already been established using modern molecular techniques. The rationale of the proposal is that by using natural populations of snakes that are ideally suited for comparative studies of inheritance, one can test a key assumption in evolutionary studies and perhaps uncover a principle of genetic constancy that applies to all species of plants and animals.
