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Asked by make1dab to Zoe V on 14 Mar 2024.
Question: what is the oldest type of DNA
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Zoe Vance answered on 14 Mar 2024:
The oldest DNA that’s ever been sequenced is about 2 million years old, from sediment in Greenland. This is a really crazy age to find DNA that we can still learn things from!
We usually consider the half life of DNA (the time it takes for half of the chemical bonds in the DNA to break down) to be about 500 years, so you can imagine that after 2 million years there would be hardly anything left! But the number changes depending on conditions, so we have some very old DNA sequences from samples that were deeply frozen, or bodies preserved in bogs etc. In the case of the Greenland sediment the authors think the DNA was better preserved than expected because it stuck itself on to minerals in the soil.
Comments
emily commented on :
thats so cool i would love to learn more.
Zoe V commented on :
There’s an interview with one of the authors at the start here: https://www.nature.com/articles/d41586-022-04376-y They talk a bit about what they learned from the DNA they were able to get out of the sediment, it’s pretty cool!