The "slim" gene variant has been found in Europe, and up to 60% of people carry this gene

• Researchers from Spain's National Cancer Research Center (CNIO) and IMDEA Food Institute found that those with specific genes related to cellular nutrition tend to accumulate less fat
  .
  

• But "it's a trend
  .
  It's not that people with this gene variant can overeat without getting fat," said
  senior co-author Alejo Efeyan (CNIO), who co-authored the paper with Ana Ramirez de Molina (IMDEA Foods).
  

• The work, published in Genome Biology, says the authors of the paper represent a breakthrough in understanding the genetic makeup of obesity, which could help with future treatments
  for the disease.
  
   

To what extent do genes influence our weight?

According to studies that have analyzed the complete genomes of tens of thousands of people in recent years, the impact on the general population is about 20%.

In other words, explains Nerea Deleyto-Seldas, a researcher at the Spanish National Cancer Research Center (CNIO), "lifestyle, such as eating habits and exercise, has a big influence, but genetic factors also play a role
.
"

Some of these genetic factors are already known
.
Nearly 100 genetic variants have been identified that modestly increase the likelihood of having a high body mass index (BMI), a common indicator
of being overweight or obese.
CNIO and IMDEA food researchers have just discovered a new bacterium
.

Variants of a gene are slightly different versions of that gene that don't normally cause visible changes
in the body.
But this time, they did
.
This variation, which affects the amount of fat stored in the body, is particularly prevalent
in Europe, the authors of the new study say.
It is estimated that almost 60% of the European population suffers from the disease
.

Ana Ramirez de Molina, head of the CNIO Metabolism and Cell Signaling Group and director of the IMDEA Food Institute, said: "This discovery is another step
forward in understanding the genetic components of obesity.
Understanding the role of cellular nutrient sensing pathways in obesity may have implications
for the development and application of personalized strategies for the prevention and treatment of obesity.
”

Genetic and physical measurements of 790 volunteers

Overweight and obesity are defined as abnormal or excessive accumulation
of fats that affect health.
To look for genetic variants that influence this phenomenon, as well as associated metabolic changes, a team from IMDEA Foods collected genetic material and data from 790 healthy volunteers, such as weight, BMI, total and visceral fat, muscle mass, waist and hip circumference, and more
.

The team analyzed possible links between these parameters and 48 specific genetic variants, which were selected based on
their possible functional relevance.
They found "a significant correlation between a variant in the FNIP2 gene and a number of obesity-related parameters," the study explains
.

Demonstration of animal models

The team then studied the effect of the variant on mice, which had previously been genetically modified to express the gene
.
"We found that mice carrying this gene variant had 10 to 15 percent less fat
than mice that did not carry this gene variant," Efeyan explains.

In humans, the effects of this variation cannot be separated from many other genetic and environmental variables that affect physical fitness, so it is impossible to accurately estimate the intensity of
its effects.
But given that genetics influence obesity by no more than 20%, the contribution of the variants identified now must be small
.

So the researchers used terms like this — tendency or trend, Efeyan explains, "not that people with this genetic variant can overeat without getting fat
.
"

The transgenic animals used for this study showed no other changes or differences
.
"This result is striking because many of these studies tend to be limited to reporting associations; In this paper, we show that changes in one letter throughout the mouse genome are sufficient to replicate what we observed in human variation," Efeyan continued
.

Relates to what cells eat

The significance of the detected variant is that it is related to a biochemical signaling pathway that tells the cell what nutrients are available
.
Why a small genetic change affects the tendency to be slim now needs to be studied
.

Nerea Deleyto adds that the goal for the future is "to better understand the molecular basis of the role of this genetic variation, i.
e.
what biochemical changes
occur in cells.
" "We need to improve genetic tools so that the functional consequences of this variation become important in the organism, for example during fat formation
," she stressed.

The findings also raise questions for other areas of science, such as what evolutionary pressures drove this selection of variation, and when it occurred
.

Folliculin-interacting protein FNIP2 impacts on overweight and obesity through a polymorphism in a conserved 3′ untranslated region