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The role of HSP90 in evolution.
1The Tokyo Metropolitan Institute of Medical Science, Honkomagome 3-18-22, Bunkyo-ku, Tokyo 113-8613, Japan. yahara@rinshoken.or.jp
Genes to Cells : Devoted to Molecular & Cellular Mechanisms
|September 1, 1999
Summary
Cryptic mutations, stored without visible effects, become active under environmental stress. This study in Drosophila reveals how these hidden genetic changes can influence evolution.
Area of Science:
- Evolutionary genetics
- Molecular biology
- Developmental biology
Background:
- Morphological mutations can exist without expressing a phenotype, a state known as cryptic variation.
- These cryptic mutations are typically neutral and accumulate without selective pressure.
- The heat shock protein 83 (Hsp83), also known as HSP90, plays a role in modulating the expression of these mutations.
Purpose of the Study:
- To unravel the mechanism by which morphological mutations are stored without expressing phenotypes.
- To investigate the role of Hsp83 (HSP90) in the storage and potential expression of cryptic genetic variation.
- To understand how environmental stress can alter the evolutionary trajectory of neutral mutations.
Main Methods:
- Genetic studies in Drosophila melanogaster.
- Analysis of Hsp83 (HSP90) function and its interaction with genetic variation.
- Exposure of flies to environmental stress to observe phenotypic changes.
Main Results:
- A mechanism for storing morphological mutations without phenotypic expression was identified.
- Cryptic mutations were confirmed to be neutral, evolving in the absence of selective constraint.
- Environmental stress was shown to induce a shift from neutral to selective mutations.
Conclusions:
- Hsp83 (HSP90) is implicated in the buffering of cryptic genetic variation.
- Environmental stress can unmask cryptic mutations, making them subject to natural selection.
- This provides a molecular basis for understanding macroevolutionary processes.