Scientists say they have identified the clearest genetic link to obesity yet. The gene is called the FTO gene. Researchers found people with two copies of this “fat gene” had a 70% higher risk of obesity than those with none. The finding promises to explain why some people easily put on weight while others with similar lifestyles stay slim.
Half of white Europeans carry one copy of the variant and one in six people has the most vulnerable genetic make-up and weighs an average 3kg more than those with the lowest risk. They also have 15 per cent more body fat.
If the biological function of the FTO gene can now be understood, it could become possible to design drugs that manipulate it to help people to control their weight. “Even though we have yet to fully understand the role played by the FTO gene in obesity, our findings are a source of great excitement,” Mark McCarthy, of the University of Oxford, who led the research, said.

Obesity FTO fat gene

It is not alone

FTO will not be the only gene that influences obesity, and inheriting a particular variant will not necessarily make anyone fat. “This is not a gene for obesity, it is a gene that contributes to risk,” Professor McCarthy said.
The research involved too many people to control for exercise and diet, so it is not yet known whether FTO affects how much people eat or how active they are. But it may explain how people with apparently similar lifestyles differ in propensity to put on weight.

Link with Diabetes

The discovery began when the researchers scanned the genetic code of nearly 5,000 British volunteers looking for genes that were associated with type II diabetes.
Obesity is associated with an increased risk of type two diabetes, and the investigators first identified the FTO gene when looking for differences between the genomes of people with type two diabetes and people without diabetes.
People with type two diabetes were more likely to have a particular variant of the FTO gene, which was also shown to be linked to increased body weight.
The variant making people fatter differed from the other version of the FTO gene by a single mutation in the DNA sequence.
The team then looked at other studies involving 40,000 people searching for this FTO mutation, and confirmed that it was associated with body weight.

Genetic evolution

The existence of genetic variations that cause weight gain is not surprising. Calorie malnutrition was probably the biggest cause of death for most of human history. So genetic variations that cause weight gain during good times would have conferred survival advantages. But why don’t all people have the same strongest tendency to weight gain? Maybe not all of us have suffered famine or food shortage, who knows.

Obesity and the Future

It’s true, the discovery of this gene hasn’t shed a lot of light over the obesity problem, but we’ve got to admit that it’s a beginning… At least now we have an excuse when we have to explain why we are gaining weight: “It’s not me, my genes are responsible”…

Sources: BBC news, Timesonline

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