Genes May Determine Body Weight by Shaping Gut Bacteria

The pair, along with their colleagues in the UK, US and Israel, analysed the gut bacteria of 977 twins based in the UK by looking at the bacterial content of their faeces. Each of the volunteers donated a sample, which the team put through a process that pulls out fragments of DNA that can be used to identify the different types of bacteria present. The team then compared how similar gut bacteria were in identical twins (which have the same set of genes) and non-identical twins (who are assumed to share a very similar environment, but do not have exactly the same genes). When the group compared the levels of similarity in gut bacteria generally, they found no difference between identical and non-identical twins, suggesting that genes don't influence the microbiome. But when they looked at the heritability of different groups of bacteria separately, they found that some bacteria were more similar in identical than in non-identical twins. In other words, some components of the microbiome are heritable. Intriguingly, the groups of bacteria that are heritable are ones that have previously been linked to disease, the team found. "It could be one of the mechanisms for genetic inheritance of disease – a route we haven't thought of before," says Spector. http://www.newscientist.com/article/dn26519-composition-of-your-gut-bacteria-may-be-inherited.html#.VFvBScknbPs