Specific Gene Expression in the Human and Non-Human Primate Epididymis

Abstract

In the few mammalian species tested, the epididymis appears to be essential for the acquisition of male in vivo fertilizing ability, and as far as can be deduced from anatomical and physiological studies, the general organization and functions of the human and non-human primate epididymis seem to be sufficiently similar to other mammals (for review, see Bedford, 1994). Therefore, it may be asked why we cannot simply predict the pattern of primate epididymal gene expression by extrapolation from studies in animal models (see chapter by Cornwall et al., this volume). Major hurdles, however, are the poor evolutionary conservation of many epididymal gene products (see below) and the lack of a suitable animal model due to the rather limited number of mammalian species investigated to date. Moreover, our understanding on a molecular level of epididymal functions is extremely limited for mammals in general, and the mechanisms by which specific epididymal products implement the acquisition of sperm fertilizing ability are largely unknown. Consequently, whether the primate epididymis provides specific gene products essential in male fertility cannot be decided a priori from other mammals, but requires detailed studies of epididymal gene expression in these species.