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The mechanisms controlling chromosome number, size, and shape, and the relationship of these traits to genome size, remain some of the least understood aspects of genome evolution. Across vascular plants, there is a striking disparity in chromosome number between homosporous and heterosporous lineages. Homosporous plants (comprising most ferns and some lycophytes) have high chromosome numbers compared to heterosporous lineages (some ferns and lycophytes and all seed plants). Many studies have investigated why homosporous plants have so many chromosomes. However, homospory is the ancestral condition from which heterospory has been derived several times. Following this phylogenetic perspective, a more appropriate question to ask is why heterosporous plants have so few chromosomes. Here, we review life history differences between heterosporous and homosporous plants, previous work on chromosome number and genome size in each lineage, known mechanisms of genome downsizing and chromosomal rearrangements, and conclude with future prospects for comparative research.
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Fern Genomics: Unfurling the Mystery of Plant Chromosome Numbers
Plants are more tolerant of changes in their chromosome number than animals. Even dramatic changes, such as doubling of the entire genome, sometimes leads to beneficial outcomes. Though a history of genome doubling is common in most plants, the chromosome number in many plants does not reflect this. Complex genome downsizing processes help these plants shed extra genetic information, but are poorly understood. Through comparisons with ferns – a group with high chromosome numbers – Dr Paul Wolf from the University of Alabama in Huntsville aims to shed light on genome downsizing.
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- Award ID(s):
- 1911459
- PAR ID:
- 10200028
- Date Published:
- Journal Name:
- Scientia
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.33548/SCIENTIA543
