Navigation Links
Penn biologists explain how organisms can tolerate mutations, yet adapt to environmental change
Date:1/20/2010

PHILADELPHIA - Biologists at the University of Pennsylvania studying the processes of evolution appear to have resolved a longstanding conundrum: How can organisms be robust against the effects of mutations yet simultaneously adaptable when the environment changes?

The short answer, according to University of Pennsylvania biologist Joshua B. Plotkin, is that these two requirements are often not contradictory and that an optimal level of robustness maintains the phenotype in one environment but also allows adaptation to environmental change.

Using an original mathematical model, researchers demonstrated that mutational robustness can either impede or facilitate adaptation depending on the population size, the mutation rate and a measure of the reproductive capabilities of a variety of genotypes, called the fitness landscape. The results provide a quantitative understanding of the relationship between robustness and evolvability, clarify a significant ambiguity in evolutionary theory and should help illuminate outstanding problems in molecular and experimental evolution, evolutionary development and protein engineering.

The key insight behind this counterintuitive finding is that neutral mutations can set the stage for future, beneficial adaptation. Specifically, researchers found that more robust populations are faster to adapt when the effects of neutral and beneficial mutations are intertwined. Neutral mutations do not impact the phenotype, but they may influence the effects of subsequent mutations in beneficial ways.

To quantify this idea, the study's authors created a general mathematical model of gene interactions and their effects on an organism's phenotype. When the researchers analyzed the model, they found that populations with intermediate levels of robustness were the fastest to adapt to novel environments. These adaptable populations balanced genetic diversity and the rate of phenotypically penetrant mutations to optimally explore the range of possible phenotypes.

The researchers also used computer simulations to check their result under many alternative versions of the basic model. Although there is not yet sufficient data to test these theoretical results in nature, the authors simulated the evolution of RNA molecules, confirming that their theoretical results could predict the rate of adaptation.

"Biologists have long wondered how can organisms be robust and also adaptable," said Plotkin, assistant professor in the Department of Biology in Penn's School of Arts and Sciences. "After all, robust things don't change, so how can an organism be robust against mutation but also be prepared to adapt when the environment changes? It has always seemed like an enigma."

Robustness is a measure of how genetic mutations affect an organism's phenotype, or the set of physical traits, behaviors and features shaped by evolution. It would seem to be the opposite of evolvability, preventing a population from adapting to environmental change. In a robust individual, mutations are mostly neutral, meaning they have little effect on the phenotype. Since adaptation requires mutations with beneficial phenotypic effects, robust populations seem to be at a disadvantage. The Penn-led research team has demonstrated that this intuition is sometimes wrong.


'/>"/>

Contact: Jordan Reese
jreese@upenn.edu
215-573-6604
University of Pennsylvania
Source:Eurekalert

Related biology news :

1. Biologists merge methods, results from different disciplines to find new meaning in old data
2. New handbook for biologists who need more competence or confidence in statistics
3. Biologists discover bacterial defense mechanism against aggressive oxygen
4. Beyond genomics, biologists and engineers decode the next frontier
5. Biologists, educators recognize excellence in evolution education
6. NIMBioS hosts tutorial on optimal control and optimization for biologists
7. Biologists discover death stench is a universal ancient warning signal
8. UTSA plant biologists publish where their peers are -- on the Web
9. Microbiologists find defense molecule that senses respiratory viruses
10. Geobiologists propose that the earliest complex organisms fed by absorbing ocean buffet
11. Biologists rediscover endangered frog population
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/20/2016)... DALLAS , June 20, 2016 ... criminal justice technology solutions for public safety, investigation, ... by the prisons involved, it has secured the ... Corrections (DOC) facilities for Managed Access Systems (MAS) ... (4) additional facilities to be installed by October, ...
(Date:6/7/2016)... -- Syngrafii Inc. and San Antonio Credit Union (SACU) ... Syngrafii,s patented LongPen™ eSignature "Wet" solution into SACU,s ... in greater convenience for SACU members and operational ... document workflow and compliance requirements. Logo ... Highlights: ...
(Date:6/1/2016)... NEW YORK , June 1, 2016 ... Biometric Technology in Election Administration and Criminal Identification to ... According to a recently released TechSci Research report, " ... Sector, By Region, Competition Forecast and Opportunities, 2011 - ... $ 24.8 billion by 2021, on account of growing ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... June 24, 2016  Regular discussions on a range of ... between the two entities said Poloz. Speaking at ... Ottawa , he pointed to the country,s inflation target, ... government. "In certain ... institutions have common economic goals, why not sit down and ...
(Date:6/24/2016)... ... ... While the majority of commercial spectrophotometers and fluorometers use the z-dimension of ... higher end machines that use the more unconventional z-dimension of 20mm. Z-dimension ... of the cuvette holder. , FireflySci has developed several Agilent flow cell product ...
(Date:6/23/2016)... ... June 23, 2016 , ... ... its second eBook, “Clinical Trials Patient Recruitment and Retention Tips.” Partnering with experienced ... this eBook by providing practical tips, tools, and strategies for clinical researchers. , ...
(Date:6/23/2016)... 2016   Boston Biomedical , an industry ... to target cancer stemness pathways, announced that its ... Drug Designation from the U.S. Food and Drug ... including gastroesophageal junction (GEJ) cancer. Napabucasin is an ... cancer stemness pathways by targeting STAT3, and is ...
Breaking Biology Technology: