The human fertilin alpha gene is non-functional: implications for its proposed role in fertilization.
In the guinea-pig, the alpha subunit of the fertilin complex, a heterodimeric surface membrane glycoprotein found on the head region of spermatozoa, has previously been proposed to mediate membrane fusion with the oolemma plasma membrane during fertilization. Here we describe experiments which indicate that the only fertilin alpha-like gene in humans is an expressed, but nonfunctional, pseudogene, possibly derived by genetic recombination between the two fertilin alpha genes found in some primates. This finding clearly raises questions about the importance and/or role of fertilin alpha in mammalian fertilization.