Navigation Links
Desert woodrats switch one dietary poison for another
Date:4/7/2009

As the U.S. Southwest grew warmer between 18,700 and 10,000 years ago, juniper trees vanished from what is now the Mojave Desert, robbing woodrats of their favorite food.

Now biologists have narrowed the hunt for detoxification genes that let the rodents eat the toxic creosote bushes that replaced junipers.

"It was either eat it or move out," says biologist Denise Dearing of the University of Utah, lead author of a paper detailing the results, published on-line on April 7, 2009, in the journal Molecular Ecology.

"This is an excellent example of research that bridges the fields of ecology and physiology," says Mary Chamberlin, acting deputy division director of the National Science Foundation (NSF)'s Division of Integrative Organismal Systems, which funded the research.

"It underscores the importance of studying organismal biology in order to understand how animals may or may not adapt to changes in their ecosystems."

During the study, eight woodrats were captured from each of two western regions: the Mojave Desert and the cooler Great Basin. Rats from both areas were fed rabbit chow mixed with either creosote or juniper.

The scientists then scanned the rodents' genetic blueprints to look for active genes known as "biotransformation genes" because they produce liver enzymes to detoxify the poisons in creosote and the less-toxic juniper.

"We found 24 genes in woodrats from the Mojave Desert that could be key in allowing them to consume leaves from creosote bushes," Dearing says. "The leaves are coated with a toxic resin that can comprise up to 24 percent of the dry weight of the plant."

She conducted the study because "we don't really know how herbivores can feed on toxic diets. If we can understand it, we may be able to learn how they will deal with climate change.

"For example, the toxins in creosote could respond to increases in atmospheric carbon dioxide," she says. "The plants may make more toxins under increased carbon dioxide conditions."

Even with detoxification genes, creosote bush is so toxic the woodrats can eat only so much. When they eat it exclusively, in winter, they lose weight. In spring, they gain weight when they also eat other plants.

Juniper is also toxic, but not as much as creosote bush.

Before creosote came to the Southwest from South America, woodrats ate juniper throughout what is now the Great Basin of Utah and Nevada and the Mojave Desert of southwestern Utah, southern Nevada and inland southeastern California.

But things changed as the last Ice Age waned.

As the glaciers receded, creosote bush invaded. The Southwestern deserts formed as the land became hotter and drier, and creosote bush replaced juniper trees in those areas.

Dearing says that as creosote invaded, some woodrats already had genes to let them eat creosote, or there was a mutation in existing detoxification genes that allowed for creosote consumption.

Over time, Mojave woodrats with those genes were more likely to survive on creosote, while those in the Great Basin stuck to juniper.


'/>"/>

Contact: Cheryl Dybas
cdybas@nsf.gov
703-292-7734
National Science Foundation
Source:Eurekalert  

Related biology news :

1. UNCCD recognizes importance of satellites for combating desertification
2. Tiny dust particles from Asian deserts common over western United States
3. Small desert beetle found to engineer ecosystems
4. Geology and biology meet in the history of US southwestern desert surface waters
5. Switching goals
6. Researchers find signal that switches on eye development -- could lead to eye in a dish
7. Researchers identify how to switch off cancer cell genes
8. Leading cause of death in preemies might be controlled by resetting a molecular switch
9. Why the switch stays on
10. Electronic switch opens doors in rheumatoid joints
11. Search for the on switches may reveal genetic role in development and disease
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Desert woodrats switch one dietary poison for another
(Date:1/25/2016)... Unisys Corporation (NYSE: UIS ) today announced the implementation ... New York City , to help U.S. ... the United States using passports that are ... of the system at Dulles last year. The system will ... 2016. --> pilot testing of the system at ...
(Date:1/21/2016)... January 21, 2016 ... new market research report "Emotion Detection and Recognition Market by ... Tools (Facial Expression, Voice Recognition and Others), Services, ... forecast to 2020", published by MarketsandMarkets, the global ... reach USD 22.65 Billion by 2020, at a ...
(Date:1/18/2016)... Jan. 18, 2016  Extenua Inc., a pioneering ... the use and access of ubiquitous on-premise and ... with American Cyber.  ... leading transformational C4ISR and Cyber initiatives in support ... latest proven technology solutions," said Steve Visconti ...
Breaking Biology News(10 mins):
(Date:2/9/2016)... (PRWEB) , ... February 09, 2016 , ... The ... the organization’s history, it is offering its 2016 AAT Member Certification Qualification Course for ... The curriculum for the webinar, which will include a detailed review of hardware, software, ...
(Date:2/9/2016)... , ... February 09, 2016 , ... ... Vice President for Public Policy for the National Organization for Rare Disorders (NORD). ... groups to ensure their voices are heard throughout the drug regulatory review process. ...
(Date:2/9/2016)... YORK , Feb. 9, 2016 This ... analyzes the current and future prospects of the market ... this report include companies engaged in the manufacture of ... an executive summary with a market snapshot providing the ... scope of this report. This section also provides the ...
(Date:2/9/2016)... -- Three-Year Initiative Supports Next Generation of Medical ... Life-Changing Camp Experiences ... the lives of children born with rare diseases, as well as ... is announcing a new initiative designed to positively affect the lives ... of rare disease care. --> To mark the company,s ...
Breaking Biology Technology: