Health & Medicine
Human DNA Reveals Traces of Heated Battle Between Primate and Pathogen
Catherine Griffin
First Posted: Dec 12, 2014 09:22 AM EST
Some human DNA may reveal an evolutionary war against infectious bacteria over iron that circulates in the host's bloodstream. Scientists have examined DNA from 21 primate species to discover the vital importance of a defense strategy called nutritional immunity.
"We've known about nutritional immunity for 40 years," said Matthew Barber, one of the researchers, in a news release. "What this study shows us is that over the last 40 million years of primate evolution, this battle for iron between bacteria and primates has been a determining factor in our survival as a species."
After an infection occurs--such as when you experience sneezing and a runny nose-the immune system attempts to rid the body of foreign invaders. Yet scientists know less about the defense against invasive microbes, called nutritional immunity, that take place under our skin. This defense mechanism starves infectious bacteria by hiding circulating iron. More specifically, the protein that transports iron in the blood, transferrin, tucks the trace metal out of reach.
Yet this tactic isn't enough to keep some invaders at bay. Bacterial invaders-specifically, those that cause meningitis, gonorrhea and sepsis-are able to use a transferrin binding protein (TbpA) that latches onto transferrin to steal its iron.
"Interactions between host and pathogen are transient and temporary," said Nels Elde, one of the researchers, in a news release. "It took casting a wide net across all of primate genetic diversity to capture the significance."
Although the researchers charted the details of this struggle over evolutionary history, they found some interesting details when it comes to more recent events. They found that about 25 percent of people in the world's population has a small alteration in the transferrin gene, which prevents recognition by several infectious bacteria.
"Up until this study no one had come up with a functional explanation for why this variation occurs at an appreciable frequency in human populations," said Elde. "We now know that it is a consequence of the pathogens we and our ancestors faced over millions of years."
The findings are published in the journal Science.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
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First Posted: Dec 12, 2014 09:22 AM EST
Some human DNA may reveal an evolutionary war against infectious bacteria over iron that circulates in the host's bloodstream. Scientists have examined DNA from 21 primate species to discover the vital importance of a defense strategy called nutritional immunity.
"We've known about nutritional immunity for 40 years," said Matthew Barber, one of the researchers, in a news release. "What this study shows us is that over the last 40 million years of primate evolution, this battle for iron between bacteria and primates has been a determining factor in our survival as a species."
After an infection occurs--such as when you experience sneezing and a runny nose-the immune system attempts to rid the body of foreign invaders. Yet scientists know less about the defense against invasive microbes, called nutritional immunity, that take place under our skin. This defense mechanism starves infectious bacteria by hiding circulating iron. More specifically, the protein that transports iron in the blood, transferrin, tucks the trace metal out of reach.
Yet this tactic isn't enough to keep some invaders at bay. Bacterial invaders-specifically, those that cause meningitis, gonorrhea and sepsis-are able to use a transferrin binding protein (TbpA) that latches onto transferrin to steal its iron.
"Interactions between host and pathogen are transient and temporary," said Nels Elde, one of the researchers, in a news release. "It took casting a wide net across all of primate genetic diversity to capture the significance."
Although the researchers charted the details of this struggle over evolutionary history, they found some interesting details when it comes to more recent events. They found that about 25 percent of people in the world's population has a small alteration in the transferrin gene, which prevents recognition by several infectious bacteria.
"Up until this study no one had come up with a functional explanation for why this variation occurs at an appreciable frequency in human populations," said Elde. "We now know that it is a consequence of the pathogens we and our ancestors faced over millions of years."
The findings are published in the journal Science.
For more great science stories and general news, please visit our sister site, Headlines and Global News (HNGN).
See Now: NASA's Juno Spacecraft's Rendezvous With Jupiter's Mammoth Cyclone