In the following video, Fool contributor Maxx Chatsko discusses the recent investment by Johnson & Johnson (JNJ 0.87%) into a tiny start-up called Second Genome. Although terms of the deal were not disclosed, it is not believed to have been very significant. In monetary terms, anyway. Second Genome is actively pursuing links between the bacteria living in your gut -- the microbiome -- and autoimmune diseases such as ulcerative colitis. There is growing evidence suggesting the microbiome plays a big role in our overall health, so Big Pharma would be well served to follow Johnson & Johnson's lead.