Concerning the primary defect leading to the pleiotropic effects caused by anophthalmic white (Wh) in the Syrian hamster Mesocricetus auratus.

Ten physiological parameters, controlled by the pituitary-hypothalamic axis, were measured upon males of three genotypes: whwh (cream), Whwh (black eyed white) and WhWh (Anophthalmic white). Univariate analyses of variance comparing data from these hamsters indicated that the gene significantly affects six of these physiological parameters. A principal component and correlation analysis using the multivariate data indicated that of these 10 parameters, six were linearly independent and five were significantly altered by the action of the gene Wh. The results of these analyses and those previously reported suggest that the gene Wh alters the development of the embryonic diencephalon which, in turn, alters the development of the eye and pituitary leading to significant affects on the physiological parameters measured. A new method is described which should, in general, permit the determination of the primary action of a gene in the case of highly pleiotropic mutants.