On Wed, 5 Jan 2000, Damien Broderick wrote:
> >Is there not any way to establish the true age of human body,
> >like the rings on a tree?
>
> Yeah, but it's so messy. And who wants to get their leg sawn off?
>
Between sawing off legs and playing with intersex sheep, I don't
see how you aussies have time to go to the beer "tastings"...
At any rate, sawing off legs will probably not do the trick.
Bone mass tends to be highly correlated with stress put on
it, so it better reflects how much weight lifting you do.
Collagen cross linking has been used as an effective measure
of "biological" age. Steve Austad for example used it in his
studies of "aging rates" in opposums. However "chronological"
age requires something in the body that grows continuously
(perhaps only nose and ear cartilage). But these don't
grow on an "annual" basis. They are controlled more by
nutritional and genetic effects. So in my mind that leaves
perhaps only radioactive isotopes in non-recycled tissues.
That probably means only teeth. So you would need a *hyper*
sensitive mass-spectrometer to deal with long lived isotopes
like K40 (which I believe is present in the hydroxyapatite in
teeth) or a lot of material to deal with short lived isotopes
like C14 (if it is even remains in any quantities in teeth).
So, the answer to the best of my knowledge is that there is
currently no reliable way of dating the age of a human.
Robert
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