Rapid Evolution in a Post-Thermal Environment

In largemouth bass, there are two common forms of malate dehydrogenase-1 (MDH-1), which have different thermal characteristics. A population of this species not only showed an increase in the gene frequency for the thermally stable form of MDH-1 in response to thermal effluents from a nuclear production reactor, but also evolved back within 10 years to the natural frequency characteristic for the area when the man-imposed stress was eliminated. Such short-term evolutionary responses emphasize the temporally-dynamic nature of the genetic characteristics of biological resources and have implications for their management.