Science reports on a discovery researchers are putting up there with GLP-1 anti-obesity drugs. In this case, snakes can survive long, and foodless, periods of hibernation by getting rid of the genes that produce the hunger-regulating hormone named ghrelin:
Chameleons and a group of desert lizards called toadhead agamas that also have huge spaces between meals have also lost the same genes, hinting that cutting off ghrelin is a key way to excel at fasting, possibly by suppressing appetite and holding onto fat stores.
…
So in the new study, Rui Resende Pinto, an evolutionary biologist at the University of Porto, and his colleagues focused on reptiles, many of which can go long periods without food. The researchers scanned the genomes of 112 species. In snakes, chameleons, and toadhead agamas, ghrelin genes were either missing or so warped by mutations they could no longer encode the hormone, the team found. The degree of the genes’ erosion also varied considerably between snake families: Some snakes such as boas and pythons had malformed ghrelin genes, but others, such as vipers, cobras, and their relatives, barely had anything left.
“We were getting fragments, just small pieces of the sequence,” Pinto says. This difference between snake groups, he adds, may mean ghrelin was lost numerous times within snakes alone.
When the researchers looked at MBOAT4, an enzyme that makes ghrelin function, they found that it, too, was lost in snakes, chameleons, and the agamas.
…
Without ghrelin and MBOAT4, the reptiles may be able to hold onto their energy reserves for longer, letting them persist in low power mode for months to a year between meals, Pinto says.
—
You can read more of Pinto’s research here, in Royal Society Open Biology.