From “Prions Play Powerful Role in the Survival and Evolution of Wild Yeast Strains” (ScienceDaily, Feb. 15, 2012), we learn that at the Whitehead Institute,
Prions, the much-maligned proteins most commonly known for causing “mad cow” disease, are commonly used in yeast to produce beneficial traits in the wild. Moreover, such traits can be passed on to subsequent generations and eventually become “hard-wired” into the genome, contributing to evolutionary change.
Sophisticated cellular machinery ensures that replicating prion templates are chopped into pieces that can be passed to daughter cells during cell division. Importantly, the rate at which proteins switch into and out of the prion state increases in response to environmental stress, suggesting that they are part of an inherent survival mechanism that helps yeasts adapt to changes in their surroundings.
If “sophisticated cellular machinery” yields an “inherent survival mechanism” (in yeast, of all things), aren’t we really a world away from Darwin, and near to creationism?
In a massive undertaking, Whitehead Institute scientists have tested nearly 700 wild yeast strains isolated from diverse environments for the presence of known and unknown prion elements, finding them in one third of all strains. All the prions appear capable of creating diverse new traits, nearly half of which are beneficial. These unexpected findings, reported in this week’s edition of the journal Nature, stand as strong evidence against the common argument that prions are merely yeast “diseases” or rare artifacts of laboratory culture.
“We see them as part of a bet-hedging strategy that allows the yeast to alter their biological properties quickly when their environments turn unfavorable.”
Hmmm. Now we’ll know what to say the next time a Christian Darwinist asks, “What kind of a God would make prions?”
Lab head Susan Lindquist weighs in on the origin of life:
Convinced of the impact prions have had on yeast evolution, Lindquist speculates that these shape-shifting proteins may be “remnants of early life,” from a time when inheritance was predominantly protein-based rather than nucleic-acid based.
Ah, now we need only account for the sophisticated cellular machinery that forms them into a survival and evolution mechanism.
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