9507872 Spearow Recent studies have discovered major genetic differences in the control of reproduction, especially in ovarian responsiveness to hormones. Dr. Spearow has found that the hormone-induced ovulation rate (HIOR) of one strain of mice is six times higher than in a second genetic strain of mice. Furthermore, the enzyme aromatase, responsible for generating the hormone, is 16 to 21 times higher in the second strain of mice. This enzyme converts androgens into estrogens. He has found that genetic differences in these reproductive traits segregate in crosses as though they are controlled by the action of a small number of loci with major effects. The proposed studies will utilize mouse genetic models to confirm and characterize the physiological mechanisms by which genes on mouse chromosome 2 control major differences in ovarian response to gonadotropins. These studies will also characterize and clone the genes which control major genetic differences in ovarian function. Identifying genetic markers for divergent hormone responsive genotypes, and determining the physiological mechanisms through which these genes control differences in ovarian function could aid in improving and controlling reproduction in a wide range of mammalian species. ***
