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Tomato Analyzer: A Useful Software Application to Collect Accurate and Detailed Morphological and Colorimetric Data from Two-dimensional Objects
Published on: March 16, 2010
Structural differences in chromosomes distinguish species in the tomato clade
L K Anderson1, P A Covey, L R Larsen
1Department of Biology and Program in Plant Molecular Biology, Colorado State University, Fort Collins, CO 80523-1878, USA. lorinda.anderson@colostate.edu
Cytogenetic and Genome Research
|June 17, 2010
Summary
The tomato clade
Area of Science:
- Plant genetics
- Evolutionary biology
- Cytogenetics
Background:
- The tomato clade (Solanaceae) comprises 12 diploid species with conserved chromosome number and morphology.
- Previous studies suggested evolution via genic changes, not large chromosomal rearrangements, due to normal pachytene synapsis and co-linear linkage maps.
- Minor inversions were previously noted between tomato and wild relatives.
Purpose of the Study:
- To reevaluate structural chromosomal changes among tomato clade species using high-resolution electron microscopy.
- To identify subtle chromosomal differences not detectable by light microscopy.
Main Methods:
- Examined pachytene chromosome spreads (synaptonemal complexes) from 5 F(1) hybrids.
- Utilized high-resolution electron microscopy for detailed structural analysis.
Main Results:
- Observed unexpected synaptic configurations, including mismatched kinetochores, inversion loops, and reciprocal translocations.
- These structural differences were predominantly located in heterochromatic regions.
- The observed changes are unlikely to significantly impact euchromatic linkage map co-linearity due to low gene density and recombination in heterochromatin.
Conclusions:
- Substantial chromosomal structural changes have occurred within the tomato clade.
- Electron microscopy reveals cryptic chromosomal variations not evident with light microscopy.
- These findings refine our understanding of evolutionary mechanisms within the tomato clade.
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