Biologists surprised that mutations might not be so random

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www.msn.com/en-us/news/technology/biologists-surprised-to-discover-that-some-random-mutations-may-not-be-so-random/ar-AATvoY1?ocid=msedgntp


A peculiar study into malaria resistance in humans, and where and how it occurs in the population, has unexpectedly spurred a re-evaluation of the neo-Darwinist understanding of evolution.

Neo-Darwinism refers to any branch of science which combines Charles Darwin's theory of evolution by natural selection with Gregor Mendel's discipline of genetics. The overwhelming majority of biologists and geneticists are neo-Darwinists, and one primary tenet of neo-Darwinism is the idea that the genetic mutations which cause living creatures to evolve occur randomly. For humans, this means that mutations from the entirely beneficial (opposable thumbs) and the undesirable (say, those which cause obstructive sleep apnea) can be attributed to chance rather than some kind of purposeful direction. The ones that get passed on permanently do so through natural selection — that is, because they just so happen to help their hosts, who then survive longer and have more opportunities to perpetuate the mutation via reproduction.

At least, that was the prevailing assumption. A new study led by researchers from Israel and Ghana and published in the journal Genome Research reveals that, in fact, at least one helpful genetic mutation was not random at all. They specifically studied the HbS mutation, which protects people against malaria, and found that it arose more frequently within a population where malaria is endemic (Africa) than within a population where it is not (Europe). This might cause some of neo-Darwinism's tenets to be revised.

"The results showed that the malaria resistant HbS mutation arises more frequently in the population and gene where it is of adaptive significance," Dr. Adi Livnat from the University of Haifi, the study's lead researcher and corresponding author, told Salon by email. "This shows empirically for the first time a directional response of mutation to a specific long-term environmental pressure.