Scientists use CRISPR technology to study African fish that may be key to fighting longevity diseases | Science and health

Native to Africa, the turquoise killifish lives in a semi-arid region and has developed a useful biological trick to survive the long dry months that drain its muddy lakes every year. Science Alert.

The developing embryos of these fish, which are about the size of a thumb, simply stop developing – soon after they start forming a brain and heart. They remain for several months in a state of temporary rest called “kout” to wait out the end of long dry periods. Only then do they continue their normal development

Using CRISPR, scientists have discovered how the African killifish (Nothobranchius furzeri) was able to accomplish this feat: by selecting for ancient genes buried in its genome, created more than 473 million years ago.

This discovery by a team of researchers from the USA and Germany is surprising, given that fish only developed the ability to enter diapause about 18 million years ago. “Although diapause evolved relatively recently, the genes specialized for diapause are actually ancient,” explains molecular biologist Anne Brunet of Stanford University.

“We found that most of the latency-specific genes in killifish are paralogous [pares de genes] Very ancient, meaning they were duplicated in the common ancestor of all vertebrates.

Paralogs are pairs of genes created when a gene was copied and pasted into the genome, either on the same chromosome or on a separate chromosome. In addition to random mutations, this gene duplication is one of the main ways by which new genes are generated or acquire new functions.

Brunet's team found that in turquoise killifish, one gene in each pair was semi-active during diapause, while its partner was active the rest of the time. “The whole program is like night and day,” Brunet says.

Perhaps in search of ways to adapt to harsh environmental conditions, fish-like genes underwent remodeling. This has changed fat metabolism, with embryos now producing more long-chain fatty acids, which protect their genome from damage.

“Killifish are the only vertebrate species we know of that can undergo diapause at a very late stage of development,” says Param Priya Singh, a bioinformatician at the University of California, San Francisco, who led the study with computational biologist Adam Reeves of the University of California, San Francisco. . California. “They have a developing brain and a heart that stops beating in latency and then starts again.”

Now Singh and his colleagues report discovering the fat-filled survival tactic of the African turquoise killifish It can be applied to humans. “It opens the possibility of developing]strategies, including lipid-based interventions, to promote long-term tissue preservation and combat age-related diseases.”

The study was published in cell.