Male Imparts More to Embryo than Just DNA
A team of biologists have confirmed that male sperm RNAs are delivered to the oocyte along with the DNA. Specifically, paternal messenger RNAs are delivered to the egg. These might influence development and put the male’s imprint on the developing zygote. Writing in Nature,1 the researchers speculate what the finding means:
Why should spermatozoa messenger RNAs be transferred to the oocyte? Messenger RNAs encoding proteins that bind nucleic acids, such as protamine-2, are likely to be deleterious and are probably degraded following entry, and a similar fate may await other RNAs that gain access. But some may have a role in the developing zygote: for example, clusterin (also known as sulphated glycoprotein-2, or SGP-2) is delivered to the oocyte and has been implicated in cell-cell and cell-substratum interactions, enhancement of fertility rate, lipid transportation, membrane recycling, stabilization of stress proteins, and promotion or inhibition of apoptosis. These may therefore be required in the early zygote but unnecessary in the oocyte. Alternatively (or in addition), these and other unidentified molecules, such as small interfering RNAs (siRNAs), may participate in processes such as pronuclear formation, the orchestration of events leading to oocyte activation, the transition from maternal to embryonic gene control, and the establishment of imprints in early embryos.
But haven’t cloning and parthenogenesis experiments shown the male contribution to the zygote is dispensable?
However, the success of such experiments and of somatic-cell nuclear transfer is limited, as is the production of human embryonic stem cells after somatic-cell nuclear transfer. This may be because sperm RNAs contribute to early development. Transcripts that are specific to male germ cells play a role in the differentiation of embryonic stem cells and their function may not be easily replaced.
They conclude that these accessory RNAs delivered in sperm may be necessary for fertility, and may influence the developing embryo with a signature only the male can provide.
1Ostermeier et al., “Reproductive biology: Delivering spermatozoan RNA to the oocyte,” Nature 429, 154 (13 May 2004); doi:10.1038/429154a.
Men have been taking a beating lately (see 03/31/2004 headline), so this should provide some rebuttal. In this day of experimental families and marriages and test-tube reproduction, we need to realize that there is no substitute in a family for a man and a woman. This extends all the way up from the gametes to the sexual identity and role modeling of the whole person.
The origin of sexuality is the “queen of evolutionary problems.” To a Darwinist, it doesn’t make any sense. It is costly and complex. For a good treatment on the seriousness of this problem to Darwinians, see chapter 4 of the new book by Harrub and Thompson, The Truth About Human Origins (Apologetics Press, 2004). Viewed instead as a gift of God for love, pleasure, education, diversity of roles and talents and gifts, and as a picture of his intimacy with his creatures, it can be seen as not just an accident of a purposeless past, but an awe-inspiring and beautiful thing.