We do not want to worry you, but your mutations just are not what they were a million years ago. Excuse me.
By comparing the genetic changes in the offspring of various primates, researchers have found that the rate of human mutation has slowed since we separated. X-Men franchise fans might be disappointed, but the results could clarify some questions about our past.
We are intrigued by our own genetic material as long as we have been able to study it, and we have done pretty well not only mapping our genes, but also the speed with which they are changing.
"Over the past six years, several large studies have done this for humans, so we have the number of new mutations that occur in humans each year," says Søren Besenbacher, a population expert at Aarhus University.
"So far, however, there have been no good estimates of mutation rates in our closest related primates."
Researchers from the University of Aarhus and the Copenhagen Zoo collected genetic information from the parents and descendants of chimpanzees, gorillas and orangutans to help them compare their mutation rates with our own.
An analysis of their DNA sequences revealed the number of new mutations that emerged in each generation and enabled the team to compare numbers across different branches of the primate mily tree.
Compared with similar data collected on humans, and taking into account the relative differences in the age of the parents, the mutation rate in each of the ten monkey families studied was on average about 1
The results also indicate that this slowdown began relatively recently in our history, perhaps 400,000 years ago, not long before our ancestors qualified as modern humans.
This change has some fairly significant implications when it comes to using our genes as a tape measure for mapping our evolutionary past.
Like the ticking of a metronome, we can use the "beats per minute" mutating DNA to find out when two related species were the last band members of the same band. [19659002Althoughmodern-dayhumandevelopmenthadthelastpredispositiontoournextcousinthechimpanzeessharedabout10millionyearsagoIndeedastudyofourssplittoabout13millionyearsinthepast
Other genetic measures, however, might suggest a divide close to 4 million years. Just to add to the confusion, the fossil record is inconsistent with both estimates, suggesting a split approaching 8 million years ago.
The new results could help to clarify this discrepancy and tend to divide between 6 and 7 million years. 19659002] "The times of speciation, which we can now calculate on the basis of the new rate, fit much better with the times of the kind we would expect from outdated fossils of human ancestors," says lead researcher Mikkel Heide Schierup from Aarhus University.
This could also cause us to reconsider the divergence between the ancestors of Neanderthals and modern humans, and to make the reassessment of estimates based on a slightly higher mutation rate than is currently required.
What could have caused this slowdown is anyone's guess. The researchers suspect it may have something to do with our late-onset puberty and longer generations. Or changes in the environment and lifestyle.
It is unlikely that the rate at which our genes spread and help us adapt has been affected – our development has accelerated with the rate of breakage.
Knowing more about the relationship between genetic change and adaptation can do more than just help us to understand our own history. It could describe the future for the whole branch of our family tree.
"All species of apes are endangered in the wild," says Christina Hvilsom from the Copenhagen Zoo.
"Accurately Dotting Population Evolution Over time, we can get an idea of how species can cope with future climate change."
This study was published in Nature Ecology & Evolution published.