The pain of gout has been with us for millennia at least, but scientists have gone back much further in time – more than 20 million years – to bring back a gene that could help treat the condition and others like it.

When there's too much uric acid in the blood, it forms crystals in the joints and the kidneys – which then leads to gout and other problems, including kidney disease and liver damage. This overload is known as hyperuricemia .

A gene called uricase could help, by producing an enzyme that helps reduce levels of uric acid. Unfortunately, our human ancestors lost that gene millions of years ago. So, biologists Lais Balico and Eric Gaucher from Georgia State University in the US wondered whether it could be restored.

"Without uricase, humans are left vulnerable," says

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