Spermatozoal RNA: Why is it there and what does it do?

The mammalian male gamete is transcriptionally silent as a consequence of the highly condensed architecture of its chromatin and there is also little or no cytoplasm capable of supporting translation; however, we now understand that these cells carry a full complement of mRNAs and that under certain conditions, spermatozoa can translate their mRNAs de novo. Moreover, there is now good evidence that spermatozoal RNA can potentially affect phenotypic traits in offspring. This epigenetic phenomenon may involve the transmission of extra-chromosomal episomal elements. These data indicate that the spermatozoon is well matched to its role of delivering the paternal genome, but that additional male-benefits may also be accrued by the delivery of spermatozoal RNA.