Biologists ID molecular basis of high-altitude adaptation in mice
Biologists have long known how adaptive evolution works. New mutations arise within a population and those that confer some benefits to the organism increase in frequency and eventually become fixed in the population. A significant challenge for evolutionary biologists, however, has been to identify the specific mutations that are responsible for adaptive change. But new research by an international team led by Jay Storz of the University of Nebraska-Lincoln has succeeded in identifying the specific gene mutations that have allowed deer mice to migrate from grasslands at relatively low elevations to low-oxygen alpine peaks.
In a paper published in the Aug. 10-14 online edition of the Proceedings of the National Academy of Sciences, Storz and his team describe findings from a population genetic analysis of 75 wild deer mice captured in Colorado -- 38 at about 3,300 feet above sea level in Yuma County near the Kansas border and 37 at the peak of 14,345-foot Mount Evans in Clear Creek County.
Animals in high-altitude, low-oxygen environments such as those at the top of Mount Evans are subject to hypoxia, a condition that results when arterial blood does not carry a sufficient supply of oxygen to bodily tissues. Among the high-altitude mice, however, Storz and his team found mutations in four different hemoglobin genes that enable the animals to tolerate chronic hypoxia.
The mutations found in high-altitude mice increase the oxygen-binding affinity of hemoglobin, which in turn augments the concentration of oxygen in the arterial bloodstream. The mutations were absent in the low-altitude mice.
"The significance of this work is that we have identified the specific mutations involved in evolutionary adaptation to different environments," Storz said. "One of the challenges of living in a low-oxygen environment is that the arterial blood does not carry a sufficient amount of oxygen to all the cells of the body. For animals living in these low-oxygen conditions, it's often advantageous to have hemoglobin with an especially high oxygen-binding affinity. These fine-tuned adjustments in hemoglobin function provide a decisive physiological advantage to animals living in such an extreme environment.
"By using biotechnology methods, we were able to pinpoint the specific mutations that enable the high-altitude mice to tolerate chronic hypoxia. These findings provide important insights into the process of Darwinian evolution at the molecular level."
An assistant professor of biological sciences at UNL since 2005, Storz said the mutations had to have occurred in a relatively short period of time, the 10,000 years since the end of the last glacial maximum since the mice could not have colonized the alpine areas until after Ice Age conditions retreated.
He also said the hemoglobins of high-altitude deer mice are functionally similar to the fetal hemoglobins of humans. Thus, evolution has fashioned similar solutions to the physiological challenges associated with life at high altitude and those associated with pre-natal development in the hypoxic intrauterine environment.
Source: University of Nebraska-Lincoln
- Mountain mice show adaptation to altitudeFri, 2 Jul 2010, 7:32:59 EDT
- Penn biologists explain how organisms can tolerate mutations, yet adapt to environmental changeWed, 20 Jan 2010, 13:27:14 EST
- Penn researchers help solve questions about Ethiopians' high-altitude adaptationsSat, 21 Jan 2012, 0:35:14 EST
- In the race of life, better an adaptable tortoise than a fit hareTue, 22 Mar 2011, 12:33:32 EDT
- At high altitude, carbs are the fuel of choiceThu, 6 Dec 2012, 14:23:30 EST
- Biologists ID Molecular Basis Of High-altitude Adaptation In Micefrom Science DailySat, 15 Aug 2009, 0:28:07 EDT
- Biologists identify molecular basis of high-altitude adaptation in micefrom Science CentricWed, 12 Aug 2009, 7:28:06 EDT
- Biologists ID molecular basis of high-altitude adaptation in micefrom Biology News NetTue, 11 Aug 2009, 17:42:34 EDT
- Biologists ID molecular basis of high-altitude adaptation in micefrom Science BlogTue, 11 Aug 2009, 9:49:21 EDT
- Biologists identify the molecular basis of high-altitude adaptation in micefrom PhysorgMon, 10 Aug 2009, 17:42:52 EDT
Latest Science NewsletterGet the latest and most popular science news articles of the week in your Inbox! It's free!
Learn more about
Check out our next project, Biology.Net
From other science news sites
Popular science news articles
No popular news yet
No popular news yet
- Stem cell transplant restores memory, learning in mice
- Superstorm Sandy shook the US
- 2 landmark studies report on success of using image-guided brachytherapy to treat cervical cancer
- Calculating tsunami risk for the US East Coast
- Researchers discover mushrooms can provide as much vitamin D as supplements