Genome complexity: mutation rates in various species (Introduction)

by David Turell , Wednesday, April 05, 2023, 21:08 (387 days ago) @ David Turell

A massive study across species and human:

https://www.quantamagazine.org/animal-mutation-rates-reveal-traits-that-speed-evolution...

"Bergeron and her team first gathered blood and tissue samples from family trios — a mother, a father and one of their offspring — from species in zoos, farms, research institutes and museums all over the world. They then compared the DNA of the parents and the offspring in each trio to pinpoint genetic differences between the generations.

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"In the end, the researchers had 151 usable trios, representing species as physically, metabolically and behaviorally diverse as massive killer whales, tiny Siamese fighting fish, Texas banded geckos and humans.

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"The study authors found that the higher the average effective population size for a species, the lower its mutation rate. That provided good evidence for the “drift-barrier hypothesis,” which Lynch devised a little over a decade ago. “Selection is relentlessly trying to reduce the mutation rate because most mutations are deleterious,” Lynch explained. But in species with smaller effective population sizes, natural selection gets weaker because genetic drift — the effect of pure chance on the spread of a mutation — gets stronger. That allows the mutation rate to rise.

"The findings also support another idea in the scientific literature, the male-driven evolution hypothesis, which proposes that males may contribute more mutations to the evolution of some species than females do. Bergeron and her colleagues found that germline mutation rates tended to be higher for males than for females — at least in mammals and birds, though not in reptiles and fish.

"The authors noted a possible reason for those differences: Because males in all species copy their DNA constantly to make sperm, they face endless opportunities for mutations to occur. Female fish and reptiles make eggs throughout their lifetimes too, so they run a similar risk of genetic error. But female mammals and birds are essentially born with all the egg cells they will ever produce, so their germlines are more protected.

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"Factors like maturation time and numbers of offspring also played a role for some vertebrates, but contrary to expectations, the researchers didn’t find any effect related to body size. There’s a long-standing hypothesis that creatures with bigger body sizes should have more mutations because they have more cells and thus more opportunities for the DNA-copying machinery to make mistakes.

“.It was surprising to see that generation time seemed a lot more important than body size,” said Kelley Harris, an assistant professor of genome sciences at the University of Washington. “In the previous literature, those hypotheses are more on equal footing.'”

Comment: again the support for the thesis that mutations in genomes are dangerous. This is natural evolution as seen by Darwinists. Nit the way God does it, I assume.