London, Nov 7 (IANS): Our genetic makeup influences whether we are fat or thin by shaping which types of microbes thrive in our body, shows a study.

Researchers at King's College London and Cornell University have identified a specific, little known bacterial family that is highly heritable and more common in individuals with low body weight.

"Our findings show that specific groups of microbes living in our gut could be protective against obesity - and that their abundance is influenced by our genes," said Tim Spector, professor at King's College London.

The results may help for personalised probiotic therapies to reduce the risk of obesity-related diseases based on an individual's genetic make-up, showed the study.

For the study, researchers sequenced the genes of microbes found in over 1,000 fecal samples from 416 pairs of twins.

The type of bacteria whose abundance was most heavily influenced by host genetics was a recently identified family called 'Christensenellaceae'.

Members of this health-promoting bacterial family were more abundant in individuals with a low body weight than in obese individuals, said the study.

This microbe also protected against weight gain when transplanted into mice.

Mice that were treated with this microbe gained less weight than untreated mice, suggesting that increasing the amounts of this microbe may help to prevent or reduce obesity, found the study.

These results will also help us find new predictors of disease and aid prevention, concluded Ruth Ley, associate professor at Cornell University, US.