Two types of gut bacteria merge into one
Campylobacter jejuni and Campylobacter coli are exchanging genes by merging into a single species, scientists say.
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
animals.
“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 animals.
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 — 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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