King 9409464 Genes and hormones strongly influence animal behavior and morphology. As a consequence both are likely to be important in producing differences in behavior and morphology among individuals, among populations, and among species. Unfortunately, information on the interplay between genes and hormones in generally lacking. This study addresses this need by focusing on the effects of genes and hormones on the behavior on the behavior of the garter snake, Thamnophis sirtalis. The research combines methods from quantitative genetics and endocrinology by coupling hormone manipulations with analyses of behavioral, morphological, and hormonal variation within and among families of laboratory-reared garter snakes. Because hormonal influences on behavior and morphology may occur before birth, data on the in utero hormonal environment of developing offspring will be included in these analyses. To determine whether patterns observed in the laboratory parallel those seen in nature, a comparable analysis of wild-caught garter snakes will conducted. Understanding the mechanisms by which variation in behavior and morphology arise is of basic significance in biology. This research will contribute to such an understanding by answering questions such as: (1) Is genetic variation in behavior and morphology mediated through hormonal mechanisms? (2) Do hormones affect multiple traits simultaneously, thus generating correlations among traits? (3) Are the processes giving rise to variation among individuals the same as those giving rise to differences between genders? The results from this research are likely to be broadly applicable to a wide variety of organisms. The genetic principles underlying this research hold for all organisms and the hormonal processes under investigation are similar for all vertebrates. With further study, this research may have applications ranging from assessment of the effects of hormone-mimicking chemicals released into the environment to treatment of geneti c disorders affecting hormonal pathways.
