Recipes For Life: How Genes Evolve | New Scientist

Home » How Evolution Builds Genes From Scratch » Recipes For Life: How Genes Evolve | New Scientist

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Illustration of a DNA molecule forming chromosomes. But how do the genes encoded in the DNA evolve?

(Image: Cosmocyte / Phanie / Rex Features)

ONCE, we could only marvel at the wonder of life. Like movie audiences not so long ago, we had little idea of what went on behind the scenes.

How times have changed. As the genomes of more and more species are sequenced, geneticists are piecing together an extraordinarily detailed “Making of…” documentary. Nowadays, we can not only trace how the bodies of animals have evolved, we can even identify the genetic mutations behind these changes.

Most intriguing of all, we can now see how genes – which are the recipes for making proteins, the building blocks of life – arise in the first place. And the story is not unfolding quite as expected.

“We can now see how genes arise in the first place. And the story is not unfolding quite as expected”

The most obvious way for a new gene to evolve is through the gradual accumulation of small, beneficial mutations. Less obvious is how an existing gene that already does something important can evolve into a different gene. The scope for such a gene to change tack without capsizing the organism that carries it is very limited. However, as biologists realised a century ago, this constraint no longer applies when mutations produce an entire extra copy of a gene.

Trillions of copies

According to the textbooks, the process by which new genes form starts with gene duplication. In the vast majority of cases one of the copies will acquire harmful mutations and will be lost. Just…

Tag » How Evolution Builds Genes From Scratch