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Rapid molecular evolution in a living fossil
Jennifer M Hay1, Sankar Subramanian, Craig D Millar
1Allan Wilson Centre for Molecular Ecology and Evolution, Institute of Molecular BioSciences, Massey University, Auckland, New Zealand.
Trends in Genetics : TIG
|February 8, 2008
Summary
The tuatara, a reptile that lived with dinosaurs, surprisingly shows the fastest molecular evolution rate among vertebrates. This finding challenges the expectation of slow molecular change based on its slow life history traits.
Area of Science:
- Evolutionary Biology
- Molecular Evolution
- Herpetology
Background:
- The tuatara is a unique New Zealand reptile, a 'living fossil' morphologically similar to its Cretaceous ancestors.
- Tuatara exhibit exceptionally slow life history traits, including metabolism, growth, reproduction, and generation time.
- These slow traits suggest an expectedly slow rate of molecular evolution.
Purpose of the Study:
- To investigate the rate of molecular evolution in tuatara.
- To determine if tuatara's slow life history correlates with a slow molecular evolutionary rate.
- To explore the relationship between neutral molecular evolution and phenotypic evolution in tuatara.
Main Methods:
- Analysis of ancient and modern tuatara DNA.
- Comparative genomics to assess molecular evolutionary rates.
- Examination of molecular and phenotypic data.
Main Results:
- Tuatara exhibit the highest rate of molecular change ever recorded in vertebrates.
- Contrary to expectations, molecular evolution in tuatara is exceptionally rapid.
- Rates of neutral molecular evolution and phenotypic evolution were found to be decoupled.
Conclusions:
- Tuatara possess a surprisingly high rate of molecular evolution, defying predictions based on their life history.
- The study reveals a decoupling of neutral molecular and phenotypic evolution in this ancient reptile.
- This research provides novel insights into vertebrate evolutionary rates and the factors driving them.
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