Many years ago, I heard the scientist and writer Stephen Jay Gould speak eloquently and convincingly about bacterial dominance. Despite what many people think about humans’ place in the scheme of things, he said, we live in a world of microbes. “The most outstanding feature of life’s history is that through 3.5 billion years this has remained, really, a bacterial planet,” he said in a 1997 interview with Mother Jones. “Most creatures are what they’ve always been: They’re bacteria and they rule the world. And we need to be nice to them.” (If it has been awhile since you’ve indulged in Gould’s wonderful prose, I highly recommend his 1996 essay “Planet of the bacteria,” available at bit.ly/SN_Gould.)
Gould would not be surprised to learn, I think, of all the rich details coming out about just how bacteria and other small-scale creatures (the archaea, fungi and viruses) exert dominance on other living things, including us. Thanks to technical advances in genetic sequencing that have made it relatively affordable and easy to take microbial censuses, scientists have been able to explore the microscopic denizens of the soil, oceans, Earth’s crust and, increasingly, the human body. Last issue, Tina Hesman Saey offered a wrap-up of some of 2013’s most exciting findings about the human microbiome (SN: 12/28/13, p. 18), the collection of all the microbial creatures that live in and on the body. In this issue, Science News considers the next frontiers of microbiome research.
New insights into how microbes influence the lives and evolution of animal species are front and center in Susan Milius’ story. Saey considers scientists’ emerging appreciation of how viruses that call humans home affect health and disease. Diet’s influence on the microbiome is examined. Former intern Jessica Shugart provides a detailed look at a consequence of humans’ intimate relationship with microbes: Many sugars in human breast milk nourish bacteria, not babies. It turns out that these sugars also tweak the baby’s immune system to help beneficial microbes colonize the gut, fend off possibly dangerous bacteria and even trigger changes in gene activity that help protect cells from pathogens. With growing evidence of such benefits, scientists are looking for ways to mass-produce these oligosaccharides.
Gould was right: The microbial world dominates our existence in ways we are just beginning to appreciate. And it will be to our benefit if we can use our growing understanding to foster a healthy relationship with the microscopic inhabitants whose turf we share.