Identification of embryonic sex by detection of H-Y antigen

Abstract

The commercial embryo transfer industry will find immediate use for a reliable, economical and practical procedure for identification of embryonic sex prior to transfer. Unfortunately, no procedure is currently available that meets these criteria. An approach under study is detection of a male-specific factor (hereafter referred to as H-Y antigen) on early embryos. Expression of H-Y antigen by cleavage-stage mouse embryos was first reported over a decade ago, but only over the past several years has detection of H-Y antigen been considered potentially useful to the embryo transfer industry. H-Y antigen is expressed as early as the eight-cell stage and is readily detectable on morulae; detection becomes more difficult at the blastocyst stage. It has been shown to be expressed by preimplantation embryos of all mammalian species studied, including the mouse, rat, pig, sheep, goat, cow and horse. For at least four of these species assays for H-Y antigen are approximately 85% accurate in identification of embryonic sex. Indirect immunofluorescence assays for embryonic H-Y antigen are compatible with survival and continued development of the embryo, but such assays involve highly subjective evaluation and classification of fluorescent embryos. Current procedures for identification of embryonic sex by detection of H-Y antigen remain largely experimental at this time.