There’s a zoo in my belly
If a cyclone tore through a book shop, how would you react if you were told it was your job to glue all of the books back together again? With ripped-up pages scattered all over the place, where would you start? A team of French microbiologists faced a similar dilemma when studying the diversity of bacteria in the human gut.
The long tube that is your digestive system is home to an immense zoo of microscopic organisms. Researchers from the National Institute of Agricultural Research in France wanted to know if we all shared similar zoos, or if the ‘animals’ in each of us varied.
Telling the difference between animals in a real life zoo is easy. Lions don’t look much like chimpanzees, and penguins are easy to pick out from the seals. Bacteria, on the other hand, can often be hard to categorise. So the microbiologists ripped them up and looked at a soup of their genes.
Taking samples of the microflora from the guts of 124 adult volunteers, the researchers extracted the microbes’ DNA until they had an enormous library of over half a million genes. In your imaginary book store, you had torn pages from a number of identical books. By matching overlapping sections of writing, you might be able to slowly work out which pages belonged to which books. The researchers did the same thing with sections of DNA, working out how many different microbes there were in each sample.
Surprisingly, they found double the variety of organisms they had expected – over one hundred and sixty different species. The bigger shock, however, was that we seem to share a significant number of microbial species, regardless of where we come from or what our lifestyles are like.
This work could be incredibly helpful in better understanding types of inflammatory bowel disease, like Crohn’s disease. Our gut’s microflora plays an essential role in digestion, vitamin production and protecting us from nasty invaders. Without their help, it’s unlikely we’d be able to survive at all.
