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LOCAL VARIATION IN THE GENETIC BASIS OF PAEDOMORPHOSIS IN THE SALAMANDER AMBYSTOMA TALPOIDEUM
Reid N Harris1, Raymond D Semlitsch1, Henry M Wilbur1
1Department of Zoology, Duke University, Durham, NC, 27706, USA.
Summary
Genetic differences in life-history traits were found between some isolated salamander populations. These findings suggest rapid evolution can occur independently of major genetic mutations.
Area of Science:
- Evolutionary biology
- Developmental biology
- Population genetics
Background:
- Life-history traits in isolated populations can evolve differently.
- Understanding the genetic basis of these traits is crucial for evolutionary studies.
Purpose of the Study:
- To test the hypothesis that local isolated populations of the salamander Ambystoma talpoideum differ in their genetic basis for life-history traits.
- To investigate the genetic architecture contributing to phenotypes, including life-history pathways and reproductive traits.
Main Methods:
- Crossed individuals within and between three populations of Ambystoma talpoideum to create F1 and F2 generations.
- Analyzed hybrid dissimilarity in F2 generation as evidence for differing genetic bases.
- Assessed genetic basis for life-history pathway (metamorphosis vs. paedomorphosis), per capita fecundity, survival, and growth rate.
Main Results:
- The genetic basis for life-history pathway and per capita fecundity differed between two populations.
- The genetic basis for life-history pathway, per capita fecundity, survival, and growth rate was similar in other population comparisons.
- Hybrid dissimilarity in F2 generation indicated distinct genetic underpinnings for traits in different populations.
Conclusions:
- Local isolated populations can exhibit differences in the genetic basis of life-history traits.
- Heterochronic shifts driving evolution between metamorphosis and paedomorphosis can evolve independently.
- Evolutionary patterns like these do not necessitate macromutations or non-microevolutionary mechanisms.
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