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Chromosome size matters: genome evolution in the cyperid clade
Tammy L Elliott1, František Zedek1, Russell L Barrett2
1Department of Botany and Zoology, Faculty of Science, Masaryk University, Kotlářská 2, 611 37 Brno, Czech Republic.
Annals of Botany
|November 7, 2022
Summary
Cyperid plants have the smallest chromosomes in seed plants. Smaller chromosomes correlate with wider geographical distribution, potentially boosting genetic diversity in this plant lineage.
Area of Science:
- Plant genomics
- Evolutionary biology
- Cytogenetics
Background:
- Variation in chromosome size is understudied in plants.
- The cyperid clade (Cyperaceae, Juncaceae, Thurniaceae) is a large vascular plant lineage with holocentric chromosomes.
Purpose of the Study:
- To investigate genome size and mean chromosome size in the cyperid clade.
- To understand the biological relevance of chromosome size variation in this lineage.
Main Methods:
- Genome size measured in 436 cyperid species using flow cytometry.
- Data analyzed using phylogenetically informed methods to compare genomic traits and environmental factors.
Main Results:
- Cyperids exhibit the smallest mean chromosome sizes among seed plants.
- Smaller chromosome size is associated with larger geographical distributions.
- A strong inverse relationship exists between mean chromosome size and number in cyperids.
Conclusions:
- Holokinetic drive may explain distinct patterns of genome and chromosome size in cyperids.
- Numerous small chromosomes may enhance genetic diversity where meiotic crossovers are limited.
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