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Gut Flora Can Keep Species Apart

I’ve been fascinated by the scientific community’s growing understanding of the key role our gut flora plays in our health and wellbeing.

Interestingly, it seems that for some species, the gut flora may function as the type of reproductive barrier which drives speciation (the process by which new species arise from evolution). From this Nature News article (which is ironically about a Science paper)

Robert Brucker and Seth Bordenstein, biologists at Vanderbilt University in Nashville, Tennessee, have found that the gut bacteria of two recently diverged wasp species act as a living barrier that stops their evolutionary paths from reuniting. The wasps have subtly different collections of gut microbes, and when they cross-breed, the hybrids develop a distorted microbiome that causes their untimely deaths.

Why did this blow my mind? Three reasons:

  1. While I had been aware that our gut bacteria could have impacts on our health, other than traumatic cases like systematic inflammatory response syndrome, I had not been aware that they could directly cause death or serious reproductive impairment.
  2. That gut flora may be partly to blame for the unique health/reproductive problems that hybrids (i.e., like a mule [horse + donkey] or a liger [lion + tiger]) experience! Or, as the article puts it:

    “This is an important and potentially groundbreaking study,” says Jack Werren, an evolutionary geneticist at the University of Rochester in New York. “It reveals that problems in hybrids can be due not just to their genetic make-up, but to interactions between their genes and associated microbes.” The next step, he says, is to “determine which genes are involved in regulating which bacteria, and how this is disrupted in hybrids”.

  3. This also means that gut flora (and hence diet and all the other factors which affect our flora) may be a major driver of evolution & speciation!

Mind blown.

Published in Blog

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