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Trends Genet. 2002 Oct;18(10):504-9.

Conservation of the segmented germband stage: robustness or pleiotropy?

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Institute of Evolutionary and Ecological Sciences, Leiden University, PO Box 9516, 2300RA Leiden University, The Netherlands.

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  • Trends Genet. 2002 Dec;18(12):658..


Gene expression patterns of the segment polarity genes in the extended and segmented germband stage are remarkably conserved among insects. To explain the conservation of these stages, two hypotheses have been proposed. One hypothesis states that the conservation reflects a high interactivity between modules, so that mutations would have several pleiotropic effects in other parts of the body, resulting in stabilizing selection against mutational variation. The other hypothesis states that the conservation is caused by robustness of the segment polarity network against mutational changes. When evaluating the empirical evidence for these hypotheses, we found strong support for pleiotropy and little evidence supporting robustness of the segment polarity network. This points to a key role for stabilizing selection in the conservation of these stages. Finally, we discuss the implications for robustness of organizers and long-term conservation in general.

[Indexed for MEDLINE]

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