DNA is a biochemical that contains genetic information. And like all other cellular ingredients, it decays if cellular systems don’t maintain it. Now, scientists are more confident about how fast it falls apart after a cell dies.
A team of researchers recently completed a thorough investigation of 158 ancient leg bones that belonged to giant extinct birds called moa, which once lived on New Zealand’s South Island. Using radiocarbon ages and measures of DNA integrity, the researchers generated a DNA decay rate with unprecedented rigor. But their results do not fit with claims from secular scientists who have found plenty of examples of intact DNA from supposedly million-year-old samples.
The moa bone researchers, publishing in the Proceedings of the Royal Society B, discovered that after only 10,000 years, DNA strands in bone would be so far dilapidated that DNA sequencers could no longer process it.1 They found that their DNA decay data best fit a logarithmic decay model, which follows the molecule’s initial disintegration into large fragments as happening faster than its later disintegration into smaller fragments. At room temperature, they measured the half-life of DNA to 521 years.2 After this time, only half of the amount of DNA present when the animal cells died should remain. And after another 521 years, only half of what remained after the first half-millennium would remain, and so on until none remains.
Inconsistent results have frustrated prior attempts to measure DNA’s decay rate, probably caused by differences in setting, nearby chemistry, amounts of water, and other factors that accelerate the inevitable chemical DNA decay. This project minimized variables by focusing on the moa bones, which experienced consistent temperature and burial conditions, and by analyzing so many of them.