Sunday, February 24, 2008

The Evil Virus that Lives Inside Me
To paraphrase Khalil Gibran (aka "The Prophet"): Our genomes are not really our genomes- they come through us, but not from us.

Our genomes are not even all 'human' - about 8% is 'virus scar' - otherwise known as HERV's "Human Endogenous Retroviruses". This DNA got there (for example) when an HIV-like virus infected the ovaries of a little squirrel-like creature a few hundred million years ago. That squirrel evolved into me, you and everyone we know.

Once this viral DNA gets in, it doesn't just stay put- it stamps itself all over the genome, making thousands of copies of itself and buggering up lots of other stuff. Like a badly graffitied library book - sometimes the meaning of the text is lost or changed.

Most of this viral DNA is just fossilized "junk"- but some (previously) viral genes have been coopted by our cells to make placentas- they allow the fusion of primitive placental cells known as "trophoblasts". Unfortunately, some also seem to be pretty good at helping good cells turn into invasive cancers.

Over the aeons, the viral DNA has become dilapidated- degraded by mutation. The genes that normally allow a HERV virus to escape from a cell are now defunct. These antique viruses are therfore trapped inside us- unable to escape and become infectious particles.

That is until 2007 when some guys decided to re-create an infectious version of HERV-K : a virus whose last outbreak was over a million years ago.

An extinct human pathogen- dormant but surviving in a crippled state through geological timescales is resurrected. We have no immunity. Bang! it's the end of the world (yet again).

What happened to "ethics committees"? Hasn't anyone read Greg Bear's novel "Darwin's Radio"?

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