Living microbes, possibly 100M years old, pulled from beneath the sea (2020)

Re:Living microbes, possibly 100M years old, pulled from ben... by patall on Tuesday January 19, 2021 @08:54AM (#25833396)

No, DNA does not have a half-life of 521 years. To give the correct citation: ''' By analysing mitochondrial DNA (mtDNA) from 158 radiocarbon-dated bones of the extinct New Zealand moa, we confirm empirically a long-hypothesized exponential decay relationship. The average DNA half-life within this geographically constrained fossil assemblage was estimated to be 521 years for a 242 bp mtDNA sequence, corresponding to a per nucleotide fragmentation rate (k) of 5.50 × 10–6 per year. With an effective burial temperature of 13.1°C, the rate is almost 400 times slower than predicted from published kinetic data of in vitro DNA depurination at pH 5. ''' from https://royalsocietypublishing.org/doi/10.1098/rspb.2012.174...

Or in laymens words: the half-life of a DNA molecule per nucleotide depends on the environment and is in the order of magnitude around 1 million years. Else, we would not have any ancient genomes by now.

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Re:Living microbes, possibly 100M years old, pulled from ben... by Ovah on Tuesday January 19, 2021 @10:37AM (#25834449)

Thank you. Yeah you hit the nail on its head: it's the environmental conditions that matter. Still it's impressive that a single whole genome has remained largely intact for 100M years or else the cell would not be able to replicate. However for the sequencing of ancient genomes no single genome has to be intact as fragments of many cells can be computationally pieced together into a complete template genome.

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