Researchers report that DNA sequences that can fold into shapes other than the classic double helix tend to have “higher mutation rates” than other regions in the human genome
“Most of the time we think about DNA as the classic double helix; this basic form is referred to as ‘B-DNA,'” said Wilfried Guiblet, co-first author of the paper, a graduate student at Penn State at the time of research and now a postdoctoral scholar at the National Cancer Institute. “But, as much as 13% of the human genome can fold into different conformations called ‘non-B DNA.’ We wanted to explore what role, if any, this non-B DNA played in variation that we see in mutation rates among different regions of the genome.” …
“When we look at all the known factors that influence regional variation in mutation rates across the genome, non-B DNA is the largest contributor,” said Francesca Chiaromonte, Huck Chair in Statistics for the Life Sciences at Penn State and one of the leaders of the research team. “We’ve been studying regional variation in mutation rates for a long time from a lot of different angles. The fact that non-B DNA is such a major contributor to this variation is an important discovery.”Penn State, “ Unusual DNA folding increases the rates of mutations” at ScienceDaily
Then we learn something else that’s interesting:
“Mutations are usually thought to be so rare, that when we see the same mutation in different individuals, the assumption is that those individuals shared an ancestor who passed the mutation to them both,” said Makova, a Penn State Cancer Institute researcher. “But it’s possible that the mutation rate is so high in some of these non-B DNA regions that the same mutation could occur independently in several different individuals. If this is true, it would change how we think about evolution.”Penn State, “ Unusual DNA folding increases the rates of mutations” at ScienceDaily
The paper is open access.
By all means change how you think about evolution. It’s a complex world out there.