I am a science geek at heart.  I don’t have the training I need to understand everything I want to — but I suspect that would still be true if I had PhDs in biology, physics, chemistry, ecology, and several others.  So I confess, the stuff that makes me say squee isn’t some ubercool blog celebrity commenting or a neato new technological gadget.  It’s stuff like a certain article in the latest issue of The Economist.

The first two-thirds of the article, about commonalities between the effects of reverse transcriptase on cancer cells versus those of zygotes in early mitosis, is interesting enough.  It’s the last part that takes my breath away:

Some of Dr Spadafora’s work is relevant to fertility treatments, too—but in a more worrisome way than Dr McKeon’s. Naked sperm (those stripped of the seminal fluid in which they normally issue forth) are more promiscuous than those still dressed in that fluid: they can pick up strands of DNA and RNA from their environment if separated from the other ingredients of semen. And they appear remarkably good at this. Dr Spadafora, for instance, claims he once found a section of frog DNA, which must have hung around in his laboratory from an experiment conducted more than a year previously, inside a mouse sperm.

This promiscuity is widespread, and has been seen in sperm from more than 30 species, from sea urchins to honey bees to humans. In many instances the foreign genes have been incorporated into embryos when the sperm fertilised an egg. In about a quarter of cases the foreign genes have appeared in the next generation. And in Dr Spadafora’s mouse experiments, reverse transcriptase in sperm has very occasionally turned foreign RNA into DNA, which has then found a place in the nuclear genome.

Although unlikely to have any effect if it did happen, the principle is cause for concern. Fertility clinics remove the seminal protection from human sperm in order to rid it of diseases. This work suggests, in theory at least, that IVF laboratories could unwittingly create transgenic humans.

Transgenic humans — that is, humans with genes borrowed from other organisms? The possibilities of what this could mean are beyond me.  It is the very idea that this is possible that takes my breath away.

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