Patterns of nucleotide variation and reproductive isolation between a Mimulus allotetraploid and its progenitor species.
Here we report our characterization of a widespread, highly selfing Mimulus allotetraploid formed by interspecific hybridization between M. nasutus and M. guttatus. Nucleotide variation at two nuclear loci (mCYCA and mAP3) within and among tetraploid populations resolves two haplotype clusters for each locus: one shares near identity with sequences from M. nasutus and the other group shares substantial variation with M. guttatus. With respect to the two loci studied, each allotetraploid individual is a 'fixed heterozygote' carrying sequences from both clusters. Moreover, mCYCA variation is consistent with at least two evolutionary origins for the Mimulus allotetraploid. We show that the allotetraploid is strongly reproductively isolated from M. nasutus and M. guttatus; interploidy crosses produce almost no viable seeds. By extension, we infer strong triploid block and argue that Mimulus allotetraploid formation might proceed in one step via the union of unreduced gametes in an M. nasutus-M. guttatus F(1) hybrid. We also discuss the potential roles of mating system and flowering asynchrony in allotetraploid establishment.
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Related Subject Headings
- Transcription Factors
- Sequence Alignment
- Seeds
- Polyploidy
- Polymerase Chain Reaction
- Plant Proteins
- Phylogeny
- Molecular Sequence Data
- Mimulus
- MADS Domain Proteins
Citation
Published In
DOI
EISSN
ISSN
Publication Date
Volume
Issue
Start / End Page
Related Subject Headings
- Transcription Factors
- Sequence Alignment
- Seeds
- Polyploidy
- Polymerase Chain Reaction
- Plant Proteins
- Phylogeny
- Molecular Sequence Data
- Mimulus
- MADS Domain Proteins