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Changes in the genes that control development can potentially make large contributions to evolution by generating new morphologies in plants and animals. However, because developmental genes frequently influence many different processes, changes to their expression carry a risk of "collateral damage." Scientists at the Max Planck Institute for Plant Breeding Research in Cologne and collaborators have now shown how gene self-repression can reduce the potential side effects of novel gene expression so that new forms can evolve. This self-regulation occurs via a distinctive molecular mechanism employing small regions of genomic DNA called low-affinity transcription factor binding sites.
Suppose a bird develops a modified wing shape that makes flying easier and could be beneficial to its survival. If this gene change also altered the bird's color, making it less attractive to mates, then the advantageous wing-shape modification would be unlikely to persist. So how does nature balance the potential for novelty with the risk of side effects that may prevent novelty from arising? Using the evolution of leaf shape as an example, an international team led by Director Miltos Tsiantis has provided fresh insight into this question.
Study - Hairy - Bittercress - Weed - Tsiantis
This new study was done in the hairy bittercress, a small weed that the Tsiantis group has developed into a model system for understanding evolution of plant form. It builds on previous work from the group in which a gene called RCO was found to have driven leaf shape diversification in mustard plants by acquiring a novel expression pattern.
RCO encodes a transcription factor, a type of protein that can turn other genes on or off, and RCO's new expression pattern resulted in the emergence of the more complex leaf shapes found in bittercress. The researchers have now shown that this change in gene expression was accompanied by RCO acquiring the ability to repress its own activity....
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