Of course, they can't protect against every onslaught, which is why we still have to depend on antibiotics to rid us of some disease-causing infections. But antibiotics don't just kill off the "bad" microbes, they wipe out the "good" ones, too. That's why antibiotic use can cause diarrhea and upset stomach: The drugs interfere with the balance of our bacterial flora, making us sick, Huffnagle explains.
But the bacterial body has made another contribution to our humanity—genes. Soon after the Human Genome Project published its preliminary results in 2001, a group of scientists announced that a handful of human genes—the consensus today is around 40—appear to be bacterial in origin.
The question that remains, however, is how exactly they got there. Some scientists argue that the genes must have been transferred to humans from bacteria fairly recently in evolutionary history, because the genes aren't found in our closest animal ancestors. Others argue that they may be ancient relics from evolutionary events that took place early in our species's history and, for reasons unknown, the genes were lost in these ancestors. It's impossible to know for sure at this point.
"There remain to my knowledge no clear cases of human genes recently acquired from bacteria," says Cédric Feschotte, a biologist at the University of Texas at Arlington. "It doesn't mean there are none, but they are not well documented."
One thing is for sure: our lives and even our identities are more closely linked to the microbial world than we may think. Bacteria do a lot to keep us healthy, and scientists are just beginning to uncover their valuable secrets. As U.I.'s Bohach says: "We do not completely understand the full impact of our bacterial flora on our health and physiology."
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7 Comments
Add CommentCould too germ free environments in infancy lead to obesity in later life?
Reply | Report Abuse | Link to thisI didn't get that from the article. Thought only that the body was less efficient at extracting nutrients without the foreign bacteria so the body needed to consume more.
Reply | Report Abuse | Link to thisThere's more information about the link between gut microbes and fat storage in these two papers:
Reply | Report Abuse | Link to thisF. Backhed, R.E. Ley, J.L. Sonnenburg, D.A. Peterson and J.I. Gordon, Host-bacterial mutualism in the human intestine, Science 307 (2005), pp. 19151920
F. Backhed, H. Ding, T. Wang, L.V. Hooper, G.Y. Koh, A. Nagy, C.F. Semenkovich and J.I. Gordon, The gut microbiota as an environmental factor that regulates fat storage, Proc Natl Acad Sci USA 101 (2004), pp. 1571815723.
So... it seems that humans definately adapt and evolve to changing environmental and biological stresses. But, if our cells and bodies are modified for the benefit of the bacteria we play host to, especially when one considers the effects on human genes; It seems the real questions are where do they end and we begin? What is making the decisions and who are we? And, is it at all possible to clearly understand the course of human evolution?
Reply | Report Abuse | Link to thisPerhaps there is a glimpse of an explanation here why some people can eat more than others and nevertheless remain slim. This is so obvious that only experts deny it. The other lesson would be that in addition to exercise, physiological and mental, preventive and curative medicine will benefit from strategies for checking for faults and repairing them in the human eco-system.
Reply | Report Abuse | Link to thisI applaud your thinking mind! It sounds as if you are searching out the answer to one of life's ultimate questions: Where do we come from? But your questioning searches deeper than that... What have you come up with so far?
Reply | Report Abuse | Link to thisA baby is born, most often one of two ways, vaginally to a mother who has an unhealthy flora due to use of anti-biotics over the course of her life (birth control pills also contribute to gut dysbiosis) or via c-section, during which mothers are given I.V. anti-biotics (many vaginal births get I.V. anti-biotics too.) Now, you've got an infant under one of these conditions plus a mother who probably wont nurse (at least long). Imbalanced gut flora and formula fed until you add solids. In America, solids = french fries, wheat products, corn products, and soy products. The American diet is a dysbiosis inducing feed lot. It gets even better for the kids. They're going to get sick so you know they're going to be exposed to anti-biotics early and often, enabling the bad flora's growth and worsening the dysbiosis symptoms.
Reply | Report Abuse | Link to thisObesity is only one thing to worry about.
The only source I've found for a reasonable approach to this problem has been the GAPS Diet. Don't let the 'P' fool you, the diet is for anyone with any gut dysbiosis (so everyone) and the author is writing a new book that will address the physiological diseases. http://gapsdiet.com/Home_Page.html
Once, healthy, humans should be able to live well and healthy with traditional food preparation techniques a al Weston A. Price Foundation. http://www.westonaprice.org/
I'm not associated with either of these 'groups', but I'm pretty impressed with what I'm learning about both.