Searches for Human H-Y by Conventional Means, and how it all began

Abstract

It would appear that H-Y has two faces, not only in regard to its fields of action, but also in regard to its deportment. On the one hand H-Y is present, and makes itself persistently felt, throughout the vertebrate phylum, wherever there are heterogametes¹; it is all-pervasive, and sees to it that a second gender arises; it sees to it that the genus, be it platyfish, rattlesnake, hippopotamus, or man does not attain a state of panfeminity. On the other hand, when it comes to immune responses, H-Y is fastidious, highly discriminating, and refuses to take action unless certain well-defined preconditions are met. We have learned from Hurme et al², from Greene et al³, and from Liew et al⁴ that even a relatively simple event, e. g. delayed type hypersensitivity (DTH), or the rejection of murine skin grafts, will not come to pass unless responders carry the b allele of the MHC locus and, in addition the b allele of the I-B sublocus. In an equally simple event, namely, the elaboration of cytotoxic cells, the I-B sublocus matters less, and what is important is the I-A sublocus. It is surprising, then, that H-Y was first observed, not while it performed its pervasive sex-determining role, but when the demanding conditions for immune responsiveness were incidentally met⁵. I shall return briefly to this aspect below.