Evolution:strange DNA shapes increase mutation rate (Evolution)

by David Turell , Thursday, February 11, 2021, 19:23 (1379 days ago) @ David Turell

A new finding:

https://www.sciencedaily.com/releases/2021/02/210209121031.htm

"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. New research shows that the elevated mutation rate in these sequences plays a major role in determining regional variation in mutation rates across the genome.

***

"'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."

"Non-B DNA can fold into a number of different conformations depending on the underlying DNA sequence. Examples include G-quadruplexes, Z-DNA, H-DNA, slipped strands, and various other conformations. Recent research has revealed that non-B DNA plays critical roles in cellular processes, including the replication of the genome and the transcription of DNA into RNA, and that mutations in non-B sequences are associated with genetic diseases.

***

"For most types of non-B DNA, the team found increased mutation rates. The differences were enough that non-B DNA mutation rates impacted regional variation in their immediate surroundings. These differences also helped explain a large portion of the variation that can be seen along the genome at the scale of millions of nucleotides.

"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,

***

"The results also have evolutionary implications.

"'We know that natural selection can impact variation in the genome, so for this study we only looked at regions of the genome that we think are not under the influence of selection," said Yi-Fei Huang, assistant professor of biology at Penn State and one of the leaders of the research team. "This allows us to establish a baseline mutation rate for each type of non-B DNA that in the future we could potentially use to help identify signatures of natural selection in these sequences." (my bold)

***

"'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.'"

Comment: So again we see mutations that have no relation to required adaptation/survival as Darwinists insist must drive evolution. My bold notes their statement that they think there are areas of DNA where selection cannot work. That whole thought surprises me as I don't understand how they know some parts of DNA cannot be changed. Natural selection can only react passively on what DNA presents. A puzzle. The other puzzling statement is in the last paragraph where they do not seem to recognize the concept of convergence, which is known to cause simultaneous similar DNA changes in different individuals.