Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Athletic frogs have faster-changing genomes

13.04.2012
Physically fit frogs have faster-changing genomes, says a new study of poison frogs from Central and South America.

Stretches of DNA accumulate changes over time, but the rate at which those changes build up varies considerably between species, said author Juan C. Santos of the National Evolutionary Synthesis Center in Durham, North Carolina.


This is Dendrobates leucomelas, a poisonous frog from Venezuelan Guiana. Credit: Photo courtesy of Cesar Barrio-Amoros (www.andigena.org)

In the past, biologists trying to explain why some species have faster-changing genomes than others have focused on features such as body size, generation time, fecundity and lifespan. According to one theory, first proposed in the 1990s, species with higher resting metabolic rates are likely to accumulate DNA changes at a faster rate, especially among cold-blooded animals such as frogs, snakes, lizards and fishes. But subsequent studies failed to find support for the idea.

The problem with previous tests is that they based their measurements of metabolism on animals at rest, rather than during normal physical activity, Santos said.

"Animals rarely just sit there," Santos said. "If you go to the wild, you'll see animals hunting, reproducing, and running to avoid being eaten. The energetic cost of these activities is far beyond the minimum amount of energy an animal needs to function."

To test the idea, Santos scoured forests in Colombia, Ecuador, Venezuela, and Panama in search of poison frogs, subjecting nearly 500 frogs — representing more than 50 species — to a frog fitness test.

He had the frogs run in a rotating plastic tube resembling a hamster wheel, and measured their oxygen uptake after four minutes of exercise.

The friskiest frogs had aerobic capacities that were five times higher than the most sluggish species, and were able to run longer before they got tired.

"Physically fit species are more efficient at extracting oxygen from each breath and delivering it to working muscles," Santos said.

To estimate the rate at which each species' genome changed over time, he also reconstructed the poison frog family tree, using DNA sequences from fifteen frog genes.

When he estimated the number of mutations, or changes in the DNA, for each species over time, a clear pattern emerged — athletic frogs tended to have faster-changing genomes.

Santos tested for other factors as well, such as body and clutch sizes, but athletic prowess was the only factor that was consistently correlated with the pace of evolution.

Why fit frogs have faster-changing genomes remains a mystery. One possibility has to do with harmful molecules called free radicals, which increase in the body as a byproduct of exercise.

During exercise, the circulatory system provides blood and oxygen to the tissues that are needed most — the muscles — at the expense of less active tissues, Santos explained.

When physical activity has stopped, the rush of blood and oxygen when circulation is restored to those tissues produces a burst of free radicals that can cause wear and tear on DNA, eventually causing genetic changes that — if they affect the DNA of cells that make eggs or sperm — can be passed to future generations.

Before you ditch your exercise routine, Santos offers some words of caution. The results don't debunk the benefits of regular physical exercise, which is known to reduce the risk of cancer, heart disease, and diabetes.

"What applies to cold-blooded animals such as poison frogs doesn't necessarily apply to warm-blooded animals such as humans," Santos said.

The findings appeared in the April 10th issue of Molecular Biology and Evolution.

CITATION: Santos, J. (2012). "Fast molecular evolution associated with high active metabolic rates in poison frogs." Molecular Biology and Evolution.

URL: http://mbe.oxfordjournals.org/content/early/2012/04/09/molbev.mss069

The National Evolutionary Synthesis Center (NESCent) is a nonprofit science center dedicated to cross-disciplinary research in evolution. Funded by the National Science Foundation, NESCent is jointly operated by Duke University, The University of North Carolina at Chapel Hill, and North Carolina State University. For more information about research and training opportunities at NESCent, visit www.nescent.org.

Robin Ann Smith | EurekAlert!
Further information:
http://www.nescent.org

More articles from Life Sciences:

nachricht Shedding light on the brown color of algae
14.07.2020 | Johannes Gutenberg-Universität Mainz

nachricht New substance library to accelerate the search for active compounds
14.07.2020 | Helmholtz-Zentrum Berlin für Materialien und Energie

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Electron cryo-microscopy: Using inexpensive technology to produce high-resolution images

Biochemists at Martin Luther University Halle-Wittenberg (MLU) have used a standard electron cryo-microscope to achieve surprisingly good images that are on par with those taken by far more sophisticated equipment. They have succeeded in determining the structure of ferritin almost at the atomic level. Their results were published in the journal "PLOS ONE".

Electron cryo-microscopy has become increasingly important in recent years, especially in shedding light on protein structures. The developers of the new...

Im Focus: The spin state story: Observation of the quantum spin liquid state in novel material

New insight into the spin behavior in an exotic state of matter puts us closer to next-generation spintronic devices

Aside from the deep understanding of the natural world that quantum physics theory offers, scientists worldwide are working tirelessly to bring forth a...

Im Focus: Excitation of robust materials

Kiel physics team observed extremely fast electronic changes in real time in a special material class

In physics, they are currently the subject of intensive research; in electronics, they could enable completely new functions. So-called topological materials...

Im Focus: Electrons in the fast lane

Solar cells based on perovskite compounds could soon make electricity generation from sunlight even more efficient and cheaper. The laboratory efficiency of these perovskite solar cells already exceeds that of the well-known silicon solar cells. An international team led by Stefan Weber from the Max Planck Institute for Polymer Research (MPI-P) in Mainz has found microscopic structures in perovskite crystals that can guide the charge transport in the solar cell. Clever alignment of these "electron highways" could make perovskite solar cells even more powerful.

Solar cells convert sunlight into electricity. During this process, the electrons of the material inside the cell absorb the energy of the light....

Im Focus: The lightest electromagnetic shielding material in the world

Empa researchers have succeeded in applying aerogels to microelectronics: Aerogels based on cellulose nanofibers can effectively shield electromagnetic radiation over a wide frequency range – and they are unrivalled in terms of weight.

Electric motors and electronic devices generate electromagnetic fields that sometimes have to be shielded in order not to affect neighboring electronic...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

International conference QuApps shows status quo of quantum technology

02.07.2020 | Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

 
Latest News

Shedding light on the brown color of algae

14.07.2020 | Life Sciences

Color barcode becomes ISO standard

14.07.2020 | Information Technology

New substance library to accelerate the search for active compounds

14.07.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>