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Homologies in leaf form inferred from KNOXI gene expression during development
Geeta Bharathan1, Thomas E Goliber, Christopher Moore
1Department of Ecology and Evolution, State University of New York, Stony Brook, NY 11794-5245, USA.
Science (New York, N.Y.)
|June 8, 2002
Summary
KNOTTEDI-like homeobox (KNOXI) gene expression in shoot apical meristems correlates with complex leaf development. However, final leaf form may not accurately predict evolutionary relationships due to developmental plasticity.
Area of Science:
- Plant developmental biology
- Evolutionary botany
- Genetics
Background:
- KNOTTEDI-like homeobox (KNOXI) genes are crucial regulators of plant development, particularly leaf formation from the shoot apical meristem (SAM).
- Leaf morphology is a key trait used in plant classification and understanding evolutionary relationships (homology).
Purpose of the Study:
- To investigate the relationship between KNOXI gene expression patterns in the SAM and the resulting leaf morphology across diverse vascular plants.
- To determine if KNOXI expression in early development can predict final leaf form and its implications for inferring homology.
Main Methods:
- Analysis of KNOXI gene expression patterns within the shoot apical meristems (SAMs) of various vascular plant species.
- Comparative morphological analysis of leaf primordia and mature leaves.
Main Results:
- A correlation was observed between KNOXI gene expression and the development of complex leaf primordia in the SAM.
- It was found that complex leaf primordia can mature into simple leaves, indicating developmental plasticity.
- Final leaf morphology is not always a reliable indicator of homology due to variations in developmental pathways.
Conclusions:
- KNOXI gene expression in the SAM is linked to the initial stages of leaf complexity.
- Developmental plasticity means that early gene expression patterns do not always predict final leaf form.
- Relying solely on final leaf morphology can be misleading when inferring evolutionary relationships (homology) between plant species.
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