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Constraint and developmental dissociation of phenotypic integration in a genetically accommodated trait
Yuichiro Suzuki1, H Frederik Nijhout
1Department of Biology, Duke University, Durham, NC 27708, USA. ysuzuki@wellesley.edu
Evolution & Development
|November 22, 2008
Summary
Maladaptive traits linked to body size evolution can be removed by understanding developmental integration. Juvenile hormone (JH) constrains some trait evolution, but not all, allowing for adaptation.
Area of Science:
- Evolutionary biology
- Developmental biology
- Genetics
Background:
- Correlated traits can constrain adaptive evolution.
- The removal of maladaptive correlated traits is poorly understood.
- Body size evolution can be a correlated trait during selection for other phenotypes.
Purpose of the Study:
- Investigate the developmental basis of correlated body size evolution.
- Determine if maladaptive correlated traits can be removed.
- Explore the role of juvenile hormone (JH) in trait integration and evolution.
Main Methods:
- Artificial selection for polyphenism and monophenism.
- Investigated developmental integration between body size and coloration.
- Measured juvenile hormone (JH) titers.
- Attempted to uncouple correlated traits.
Main Results:
- Body size and coloration are developmentally integrated via juvenile hormone (JH) titers.
- Artificial selection resulted in correlated body size evolution.
- Attempts to uncouple traits led to the evolution of critical weight but not the delay period.
- The evolution of the delay period was constrained by JH titers.
Conclusions:
- Maladaptive correlated traits can be removed when multiple developmental modules exist.
- The evolution of unconstrained developmental modules facilitates adaptation.
- Juvenile hormone (JH) plays a key role in developmental integration and evolutionary constraints.
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