Samuel Sheppard, an evolutionary microbiologist at Oxford University in the
UK, together with his colleagues reached their conclusions by analysing DNA, or
genetic information, from the bacteria found inside both wild and farm
"What we're seeing here is hybridisation, and it's only been recently
acknowledged as an important part of evolution," said Sheppard.
Life Science reports that C. jejuni and C. coli are thought to have shared a
common ancestor, or parent, in the ancient past. When the microbial descendent
split up and evolutionary pressures stepped in, two new species began to take
shape and fill different niches within the guts of wild pigs, chickens and other
Despite sharing about 85% of their genetic code, the two microbes are
strikingly different, says Sheppard, adding that the bacteria likely began
reversing their growing divergence, or genetic separation, when human
agriculture came along.
Intensive farming is the key
Sheppard feels that the
bacterial merger has accelerated in recent years, as the demand for food has put
pressure on farms to become more crowded. "We're now really packing a bunch of
livestock together, and so the bacterial environment is changed."
"By altering their environment, we're altering the bacteria, their very
being," says Sheppard, noting that chickens often mistake their feathered
friends' poop for food â€” and that creates a consistent, rapid way of mixing of
two intestinal organisms that were once ecologically separated.
Sheppard explained that bacteria try and most often fail to trade genes, but
when two descendants from the same parent meet and then mate, he said, the
chance of successfully trading genes gets a boost. He couldn't say when the two
life forms might finally merge, but thinks evolutionary pressures created by
humans will surely speed things up.
"The big message here is that we're directly messing with species by messing
with their natural environments," Sheppard said.
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