A role for nonadaptive processes in plant genome size evolution?
Kenneth D Whitney1, Eric J Baack, James L Hamrick
1Department of Ecology and Evolutionary Biology, Rice University, 6100 Main St., Houston, Texas 77005, USA. kwhitney@rice.edu
Evolution; International Journal of Organic Evolution
|February 13, 2010
Summary
Seed plant genome size is not explained by the Lynch and Conery hypothesis linking genome size to effective population size (N(e)) and mating systems. Further research is needed to clarify these relationships.
Area of Science:
- Evolutionary Biology
- Genomics
- Plant Science
Background:
- Genome size variation across species is widespread but lacks comprehensive explanations.
- The Lynch and Conery hypothesis proposes genome expansion is maladaptive, driven by small effective population size (N(e)) reducing natural selection efficacy.
- Mating systems may influence genome size evolution through effects on N(e) and transposable element (TE) dynamics.
Purpose of the Study:
- To comparatively analyze the influence of effective population size (N(e)) and mating systems on genome size evolution in seed plants.
- To test the validity of the Lynch and Conery hypothesis in seed plant lineages.
- To investigate the interplay between N(e), mating systems, and genome size.
Main Methods:
- Comparative analysis of 205 seed plant species with genome size estimates.
- Correction for recent polyploidy in genome size data.
- Phylogenetically independent contrast analyses to account for evolutionary relationships.
Main Results:
- Raw data showed a positive correlation between outcrossing and genome size, and a negative correlation between N(e) and genome size.
- Phylogenetic analyses revealed only a weak association between outcrossing and genome size, and no significant relationship with N(e).
- No significant N(e) x outcrossing interaction was detected in either analysis.
Conclusions:
- The Lynch and Conery mechanism for genome size evolution is not supported by the data from seed plants.
- Mating systems may have complex effects on genome size evolution, influencing both selection efficacy and TE transmission.
- Additional research is required to fully elucidate the roles of mating systems and N(e) in shaping genome size variation.
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