e hënë, gusht 08, 2005

Luck of the Draw

Nat. Genet. 10.1038/ng1608 (2005). Genetically identical organisms that have been raised in identical environments age at different rates, suggesting that in addition to genes and environment, chance physiological phenomena can influence life span. Rea et al. report that the stress response system of Caenorhabditis elegans is subject to an underlying physiological randomness that affects how it copes with environmental insults. They placed the gene encoding green fluorescent protein (GFP) under the control of the regulatory region from the gene encoding a heat shock protein, creating an easily scored biomarker. Upon exposure to heat, isogenic worms exhibited considerable variation in fluorescence, and those expressing the highest amount of GFP tolerated heat the best and lived the longest. The physiological state indexed by GFP expression level was not heritable, and the authors suggest that stochastic variation in molecular and biochemical reactions could account for the variation in individual robustness and longevity. -- LDC