How evolution builds genes from scratch

… The ability of organisms to acquire new genes in this way is testament to evolution’s “plasticity to make something seemingly impossible, possible”, says Yong Zhang, a geneticist at the Chinese Academy of Sciences’ Institute of Zoology in Beijing, who has studied the role of de novo genes in the human brain. ...

… But genomes contain much more than just genes: in fact, only a few per cent of the human genome, for example, actually encodes genes. Alongside are substantial stretches of DNA — often labelled ‘junk DNA’ — that seem to lack any function. Some of these stretches share features with protein-coding genes without actually being genes themselves: for instance, they are littered with three-letter codons that could, in theory, tell the cell to translate the code into a protein.
It wasn’t until the twenty-first century that scientists began to see hints that non-coding sections of DNA could lead to new functional codes for proteins. As genetic sequencing advanced to the point that researchers could compare entire genomes of close relatives, they began to find evidence that genes could disappear rather quickly during evolution. That made them wonder whether genes could just as quickly spring into being. ...

... Although de novo genes remain enigmatic, their existence makes one thing clear: evolution can readily make something from nothing. “One of the beauties of working with de novo genes,” says Casola, “is that it shows how dynamic genomes are.” ...

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