When yeast cells face environmental stress, such as exposure to hydrogen peroxide, their internal operations can begin to malfunction. For example, a particular protein misfolds and no longer functions as well. This hardly seems surprising, but as usual there is more to the story. It seems that the misfolded protein normally helps to terminate the synthesis of new proteins. But when it is misfolded, some of the newly formed proteins end up a bit longer, with more information added. And the added information is not just random garbage--it helps the cells adjust to the environmental stress which brought about the change in the first place.
Hints of this adaptation mechanism appeared with researchers found that yeast cells faced with environmental stress do not slow down or fail to function--they modify. As one writer put it, phenotypic variation in the yeast cells comes "out of the woodwork." It seems that previously hidden variation emerges, and sometimes it is advantageous in dealing with the new environmental conditions.
Furthermore, these design changes have been found to be inheritable. They can persist across generations. As one researcher summarized it, this adaptation mechanism and inheritance "allows yeast cells to exploit pre-existing genetic variation to thrive in fluctuating environments."
New research is now adding more details. It seems that the yeast has proteins that help to fine tune the process. They inhibit the protein misfolding until the environmental stress reaches critical levels. At that point the protein misfolding occurs and helps to adapt to the environmental stress. As the researchers concluded:
we find that [protein misfolding] provides yeast cells with an adaptive advantage under oxidative stress conditions, ... [protein misfolding] provides a mechanism for uncovering genetic traits that aid survival during oxidative stress conditions.
This story of yeast adaptation is one example of epigenetics--mechanisms that help organisms adapt to changing conditions, and that may pass that change along to later generations. And it is another example of the falsification of evolution's fundamental prediction that biological variation is independent of need. What we now must believe is that evolution produced sophisticated mechanisms by which evolution can occur. The absurdity of evolution is reaching new heights. Religion drives science and it matters.
