Storage of fat linked to genetic variant

Scientists in Scotland have discovered a number of genes that are highly expressed in fat tissue and lead to storage of excess fat in mice. The findings, reported in PLoS ONE, could explain why some people carry more weight than others despite sharing similar diets.

By selectively breeding mice for over 60 generations to be either naturally overweight or lean, the researchers were able to compare which genes were active in their fat tissues. The comparison flagged up a number of genes — two of which are known to be involved in obesity. However, the majority of the candidate genes that appear to be active in the fat tissues of the overweight mice had not been linked to obesity until now. These genes are predicted to prevent the breakdown of fat.

The same genes were found to be active in the overweight offspring of mice where one parent was overweight and the other lean. This adds credence to the idea that genes passed down from our parents can increase the likelihood of being overweight.

The researchers also tested what would happen if both lean and overweight mice were placed on identical high-fat diets. Their results showed that the mice that started off lean had a tendency to break down fat more easily.

These findings suggest that individuals who are thin may have a degree of genetic protection from storing excess fat. Dr Nik Morton, lead author of the study, which was carried out at the University of Edinburgh's Centre for Cardiovascular Science, was keen to stress that genes are not the only determinant of obesity: 'While this supports the idea that genetic factors are linked to obesity, exercise and diet are still important for healthy lifestyles and can prevent most people from becoming obese'.

Dr Morton does however hope that his research could lead to the development of anti-obesity drugs: 'If we can identify the genes and proteins that are controlling how fat we get, we may be able to target them with medicines to try and target the obese or the consequences of obesity'.