New Research Elucidates Directed Mutation Mechanisms

No More RM+NS

It has been known for years that organisms and populations adapt to environmental challenges by mutating DNA nucleotides that are particularly exposed during transcription. In other words, when faced with an environmental challenge a cell identifies certain genes which can help meet the challenge. But the gene might require some modification. And so when the DNA double helix is unwound (in order to make a copy of the gene) the exposed single stranded DNA is subject to mutation. Therefore mutations don’t occur randomly in the genome, but rather in the genes where they can help to address the challenge. But there is more. The gene’s single stranded DNA has certain coils and loops which expose only some of the gene’s nucleotides to mutation. So not only are certain genes targeted for mutation, but certain nucleotides within those genes are targeted in what is referred to as directed mutations. As one paper explained:

The resulting mutants provide appropriate variants for selection by the stress involved, thus accelerating evolution with minimal random damage to the genome.

Note the word appropriate, for it is key. It means that the genetic variants that are created are not random with respect to the threat. Instead, they have a far greater probability of enhancing the organism’s ability to deal with the environmental challenge.

Now follow-on research indicates that these mutagenic mechanisms are essentially the same in all living cells. Therefore these mutagenic mechanisms, which target mutations in response to environmental challenges, must have arisen very early in evolutionary history. As the paper explains:

Unique metabolic reactions to a particular environmental stress apparently target specific genes for increased rates of transcription and mutation, resulting in higher mutation rates for those genes most likely to solve the problem.

These findings contradict evolution’s prediction that mutations are random with respect to need and sometimes just happen to occur in the right place at the right time. Instead, evolution created mechanisms which directly respond to future threats. These mechanisms would, themselves, bring about evolution. In other words, evolution creates evolution. That’s incredible.