7 November 2005 - 16:52Right-To-Left, if you please!
Have you seen this movie about DNA in amber that could recreate Dinosaurs, so they could break loose and feast on skeptics? You may have heard of it. No way to measure the age of DNA?
Indeed there is. It’s called Amino Acid Racemization (AAR) and it’s not as bad as it sounds.
As stated previously, there is a good chance that proteins can still be found in amber bugs.
Amino acids are in a certain orientation while part of a living organism (right-handed, they call it) and will flip over when the organism is dead (to the left-hand orientation).
Except nobody really calls it ‘flipping.’ The proper term is ‘racemization’, although I think ‘flipping’ is cooler, so let’s stick with it.
This flipping takes time and it’s the ratio from flipped to unflipped that can give an indication of the age.
Generally AAR-ing can measure around 500 million years into the past and stay fairly accurate, but it does get a bit tricky with amber.
More recent studies show that chances to find amino acids (and ergo DNA) that survived unharmed inside amber are Slim to None.
And Slim just left town.
Proc R Soc Lond B Biol Sci 1997 Apr 22;264(1381):467-74
Department of Palaeontology,
Apparently ancient DNA has been reported from amber-preserved insects many millions of years old. Rigorous attempts to reproduce these DNA sequences from amber- and copal-preserved bees and flies have failed to detect any authentic ancient insect DNA. Lack of reproducibility suggests that DNA does not survive over millions of years even in amber, the most promising of fossil environments.
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