Genetic link between fertility and appetite

US researchers have discovered a gene that only allows women to reproduce when food is plentiful. Called TORC1, the gene is thought to have helped survival by stopping women from becoming pregnant when food was in short supply, reports Nature Medicine. When researchers studied mice that did not contain the gene, they found that they were infertile and very overweight. They now think that a lack of TORC1 may play a similar role in women with both weight and fertility problems, and Professor Marc Montminy, who led the study at Salk Institute in California, believes that the discovery of the gene could help in the development of drugs.

"This gene is crucial to the 'daisy-chain' of signals that run between body fat and the brain," he said.

"It likely plays a pivotal role in how much we, as humans, eat, and whether we have offspring."

When food supply is sufficient, the fat cells in a body produce leptin, a hormone, which turns on TORC1, decreases appetite, and allows production.

However, when food is scarce, no leptin is produced and TORC1 is switched off, preventing pregnancy when a woman may be short of energy.

This, the researchers believe, was an important evolutionary advantage during times of famine.