Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

On malaria struggle, baboons and humans have similar stories to tell

26.06.2009
Evolutionarily speaking, baboons may be our more distant cousins among primates. But when it comes to our experiences with malaria over the course of time, it seems the stories of our two species have followed very similar plots.

In humans, subtle variation in one particular gene that controls whether a protein on the surface of red blood cells gets made or not literally spells the difference between susceptibility or resistance to one form of malaria. That's because the blood protein serves as the entry point for Plasmodium vivax, one of several malaria-causing parasites that infect humans.

Now, researchers at the Duke Institute for Genome Sciences & Policy report that variation in precisely the same regulatory gene also influences baboons' chances of getting sick, by ratcheting their susceptibility to another, closely related parasite up or down.

"It's a nice example of how – in the vastness of the genome – the same gene was modified in the same way in two different species to produce the same kind of resistance," says Greg Wray, director of the IGSP's Center for Evolutionary Genomics. "That's a pretty remarkable thing when you think of all the different ways malaria resistance might have evolved."

The findings, which appeared online in Nature on June 24, also mark a turning point in primate research: they are the first to connect any functionally important genetic variation in wild primates to complex, real-life consequences for the animals.

The yellow baboons in question live in Kenya's Amboseli National Park and have been the subject of ongoing observation for nearly 40 years, making them one of the best-studied wild mammal populations in the world from a behavioral and life history standpoint.

"It used to be that our work was limited to 'skin-out' biology," says Susan Alberts, an associate professor of biology and IGSP member who has been recording the habits of the baboons for the last 25 years. Today, thanks to a growing library of sequenced primate genomes including our own, scientists can begin to delve deeper.

Graduate student Jenny Tung spent three summers out on the East African savanna, watching the baboons, collecting their DNA-laden feces, and with the help of an expert team of Kenyan field assistants, very carefully drawing blood from darted animals. Successfully darting baboons is no small feat, Tung said. You have to be within meters of the animal you are targeting, and at the same time make sure that none of the baboons catch you in the act. If they did, it would send the troop running and screaming and, in technical terms, "really mess up the field data." In the evenings, Tung processed and stored her hard-won samples in a makeshift refrigerator before shipping them off to Duke.

Once back at the lab, Tung found something in those blood samples that came as a surprise despite all the years of study. More than half of the Amboseli baboons -- some 60 percent -- were infected with the malaria-like parasite known as Hepatocystis.

"We had no idea so many of them were carrying this parasite," Alberts says. For years, researchers have tracked the baboons for any signs of injury or illness. But although the infection probably compromises the animals, they don't develop cyclical fever spikes or other immediately obvious symptoms like humans with malaria do.

In search of a genetic basis for differences in the baboons' vulnerability to infection, the researchers zeroed in on the DNA sequence surrounding the DARC gene, the same region that has been traced to malaria protection among people. Although the specifics differ from those in humans, they found that a single letter change to the genetic code -- a switch from an A to a G -- lends some baboons the ability to better fend off infection. In fact, they show, one G is good, but two are even better.

Further analysis of the baboons' blood and in cell culture confirmed that the variants influence infection rates through changes in the activity of the DARC gene. Comparison of the Amboseli baboon sequences to two other populations also showed that the DNA sequence has undergone a relatively rapid rate of evolutionary change, the mark of natural selection for malaria resistance.

The newfound parallels between baboons and humans bring the long history of conflict between parasite and host into high relief. "It's a struggle out there," Alberts says. "We often think of malaria as a contemporary problem, but it's a deep part of our history."

The study also shows the power of coupling genomics with dedicated fieldwork. "Part of what we want to do is push the envelope and show that this is doable," Wray says. With the proof of principle in hand, the next big challenge is to begin to unravel the genomic differences that may be responsible for fuzzier behavioral traits, such as social status or aggression, he added.

"It's getting easier and easier to generate genetic data," Tung says. "But it's never going to be easy to have long-term field data -- especially for primates. It takes years and years before you see the fruit of those labors. We're just at the point where it's going to really start paying off."

Collaborators on the study include Alexander Primus, Andrew Bouley and Tonya Severson, all of Duke. The work was funded by the National Science Foundation, the American Society of Primatologists, Duke University, the Duke chapter of Sigma Xi, and the Duke Institute for Genome Sciences & Policy.

Kendall Morgan | EurekAlert!
Further information:
http://www.duke.edu

More articles from Life Sciences:

nachricht Water world
20.11.2017 | Washington University in St. Louis

nachricht Carefully crafted light pulses control neuron activity
20.11.2017 | University of Illinois at Urbana-Champaign

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A “cosmic snake” reveals the structure of remote galaxies

The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.

Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...

Im Focus: Visual intelligence is not the same as IQ

Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...

Im Focus: Novel Nano-CT device creates high-resolution 3D-X-rays of tiny velvet worm legs

Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.

During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....

Im Focus: Researchers Develop Data Bus for Quantum Computer

The quantum world is fragile; error correction codes are needed to protect the information stored in a quantum object from the deteriorating effects of noise. Quantum physicists in Innsbruck have developed a protocol to pass quantum information between differently encoded building blocks of a future quantum computer, such as processors and memories. Scientists may use this protocol in the future to build a data bus for quantum computers. The researchers have published their work in the journal Nature Communications.

Future quantum computers will be able to solve problems where conventional computers fail today. We are still far away from any large-scale implementation,...

Im Focus: Wrinkles give heat a jolt in pillared graphene

Rice University researchers test 3-D carbon nanostructures' thermal transport abilities

Pillared graphene would transfer heat better if the theoretical material had a few asymmetric junctions that caused wrinkles, according to Rice University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Ecology Across Borders: International conference brings together 1,500 ecologists

15.11.2017 | Event News

Road into laboratory: Users discuss biaxial fatigue-testing for car and truck wheel

15.11.2017 | Event News

#Berlin5GWeek: The right network for Industry 4.0

30.10.2017 | Event News

 
Latest News

Antarctic landscape insights keep ice loss forecasts on the radar

20.11.2017 | Earth Sciences

Filling the gap: High-latitude volcanic eruptions also have global impact

20.11.2017 | Earth Sciences

Water world

20.11.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>