Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Different genes behind same adaptation to thin air

07.12.2012
Apparent example of convergent human evolution on 2 continents

Highlanders in Tibet and Ethiopia share a biological adaptation that enables them to thrive in the low oxygen of high altitudes, but the ability to pass on the trait appears to be linked to different genes in the two groups, research from a Case Western Reserve University scientist and colleagues shows.

The adaptation is the ability to maintain a relatively low (for high altitudes) level of hemoglobin, the oxygen-carrying protein in red blood cells. Members of ethnic populations - such as most Americans - who historically live at low altitudes naturally respond to the thin air by increasing hemoglobin levels. The response can help draw oxygen into the body, but increases blood viscosity and the risks for thrombosis, stroke and difficulties with pregnancies.

By revealing how populations can live in severe environments, the research may provide insight for managing high-altitude sickness and for treating low blood-oxygen conditions such as asthma, sleep apnea, and heart problems among all people.

How long such physiological and genetic changes take remains a question. The researchers found the adaptation in an ethnic group that has lived high in mountains of Ethiopia for at least 5,000 years, but not among a related group that has lived high in the mountains for 500 years.

The findings are reported today in the open-access online journal PLoS Genetics.

In their first comparison, the researchers found that the genes responsible for hemoglobin levels in Tibetans don't influence an ethnic group called the Amhara

The Amhara have lived more than a mile high in the Semien Mountains of northern Ethiopia for 5,000 to 70,000 years. A different variant on the Amhara genome, far away from the location of the Tibetan variant, is significantly associated with their low hemoglobin levels.

"All indications are we're seeing convergent evolution," said Cynthia Beall, professor of anthropology at Case Western Reserve University and one of the leaders of the study. Convergent evolution is when two separate populations change biologically in a similar way to adapt to a similar environment yet use different mechanisms.

"These were two different evolutionary experiments," Beall said of the mountain dwellers in Tibet and Ethiopia. "On one level—the biological response—they are the same. On another level—the changes in the gene pool—they are different."

Beall investigated the adaptations and genetic links with Gorka Alkorta-Aranburu, David Witonsky, Jonathan K. Pritchard and Anna Di Rienzo, of the University of Chicago department of human genetics, and Amha Gebremedhin of Adis Ababa University's department of internal medicine in Ethiopia.

In addition to studying the Amhara, the researchers looked for changes in physiology and genetics among a related ethnic group, the Oromo, who have lived more than a mile above sea level in the Bale Mountains of southern Ethiopia for 500 years.

They found no long-term adaptation and no genetic changes related to a low-oxygen environment.

They found the Omoro had high levels of hemoglobin, as would be expected for a lowland population.

Using the same samples collected from the Amhara and Oromo, the researchers are now studying biological traits among the groups, including ventilation, and the influence of vasoconstrictors and vasodilators on blood flow, and searching for associations with genes.

They also plan to continue research and study blood flow, especially through the heart and lungs of the highlanders, and to test the metabolic rate of mitochondria that use oxygen to create the energy on which our cells and we operate.

"We also want to find whether people with the variants for low hemoglobin levels have more children and a higher survival rate," Beall said. "That's the evolutionary payoff."

This research was funded by the National Science Foundation.

Kevin Mayhood | EurekAlert!
Further information:
http://www.case.edu

More articles from Life Sciences:

nachricht Fruit fly studies shed light on adaptability of nerve cells
17.04.2015 | Deutsches Zentrum für Neurodegenerative Erkrankungen e.V. (DZNE)

nachricht Rare monkey photographed in Congo's newest national park, Ntokou-Pikounda
17.04.2015 | Wildlife Conservation Society

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Astronomers reveal supermassive black hole's intense magnetic field

Astronomers from Chalmers University of Technology have used the giant telescope Alma to reveal an extremely powerful magnetic field very close to a supermassive black hole in a distant galaxy

Astronomers from Chalmers University of Technology have used the giant telescope Alma to reveal an extremely powerful magnetic field very close to a...

Im Focus: A “pin ball machine” for atoms and photons

A team of physicists from MPQ, Caltech, and ICFO proposes the combination of nano-photonics with ultracold atoms for simulating quantum many-body systems and creating new states of matter.

Ultracold atoms in the so-called optical lattices, that are generated by crosswise superposition of laser beams, have been proven to be one of the most...

Im Focus: UV light robot to clean hospital rooms could help stop spread of 'superbugs'

Can a robot clean a hospital room just as well as a person?

According to new research out of the Texas A&M Health Science Center College of Medicine, that is indeed the case. Chetan Jinadatha, M.D., M.P.H., assistant...

Im Focus: Graphene pushes the speed limit of light-to-electricity conversion

Researchers from ICFO, MIT and UC Riverside have been able to develop a graphene-based photodetector capable of converting absorbed light into an electrical voltage at ultrafast timescales

The efficient conversion of light into electricity plays a crucial role in many technologies, ranging from cameras to solar cells.

Im Focus: Study shows novel pattern of electrical charge movement through DNA

Electrical charges not only move through wires, they also travel along lengths of DNA, the molecule of life. The property is known as charge transport.

In a new study appearing in the journal Nature Chemistry, authors, Limin Xiang, Julio Palma, Christopher Bruot and others at Arizona State University's...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

HHL's Entrepreneurship Conference on FinTech

13.04.2015 | Event News

World Conference On Regenerative Medicine 2015: Registration And Abstract Submission Now Open

25.03.2015 | Event News

University presidents from all over the world meet in Hamburg

19.03.2015 | Event News

 
Latest News

Engineer Improves Rechargeable Batteries with MoS2 Nano 'Sandwich'

17.04.2015 | Power and Electrical Engineering

Comparing Climate Models to Real World Shows Differences in Precipitation Intensity

17.04.2015 | Earth Sciences

A blueprint for clearing the skies of space debris

17.04.2015 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>