I’m not talking about the trousers (jeans) you wore in school but can’t fit into anymore. No, skinny g-e-n-e-s genes are factors found in people who are naturally svelte. And researchers have just identified one that appears to tell the body’s adipose tissue to burn more fat.
We all know these people who can eat whatever they want, but never gain any weight. Geneticist, Josef Penninger at the University of British Columbia in Canada wondered if individuals who are effortlessly slim may hold the key to understanding obesity. Scientists interested in learning how we control our weight have traditionally focused on the things that make you fat, like diet or metabolism. But they’ve never really studied why people actually stay trim. Penninger and his team decided to turn the tables and…study the genetics of thinness.
Penninger started out by searching a database – maintained by a genome centre in Estonia – for its most slender registrants. And they weeded out people who were listed as having anorexia or other conditions that alter body fat. Then they looked for genetic markers that track with these Skinny Minnies.
One gene, in particular, caught their eye. ALK – or the gene for anaplastic lymphoma kinase – is a stretch of DNA whose mutant form has been associated with human cancers. But its normal normal function had never been established.
So the scientists made mutant fruit flies, and mutant mice in an attempt to show that the gene associated with thinness in humans makes also flies and mice skinny. And that’s exactly what they found. However, the mutant gene doesn’t cause the animals to eat less.
The researchers found that ALK acts in the brain and allows the body to burn more calories for the same food we eat. The brain literally tells fat cells to burn more of the fat they have stored away.
People, mice, and we (apparently) also flies (yes, honestly), stay skinny. That suggests that this mechanism is evolutionarily conserved from insects to humans. The scientists believe this could open up an entirely new scientific field around thinness.
There are already drugs that inhibit the cancer-causing form of ALK. Which means that ALK is, what scientists call, a druggable target.
So maybe one day we can indeed develop a pill which keeps us thin!
References
Michael Orthofer et al, Identification of ALK in Thinness. Cell, online 21-05-20