Single-Handed

Single-Handed Amino Acids Selected by Experiment  02/17/2001
Scientists at Scripps Research Institute have made polypeptides that were able to preferentially select single-handed amino-acids, according to a report in
Nature.  The single-handed peptide chains were also able to edit out the mixed ones.  The article states, “Despite its relative simplicity, the peptide system has life-like characteristics: it can induce self-replication, select for molecules of the same handedness, and avoid the accumulation of errors.  This suggests that self-replicating peptides could have played a crucial role in the emergence of life, and homochirality, on Earth.”

The experiment is clever but irrelevant to the origin of life.  The single-handedness of proteins has been a major difficulty for chemical evolution theories for decades and still is (read this explanation).  By tweaking and jury-rigging the molecules toward a predetermined outcome, these scientists injected intelligent design into the experiment.  This is a form of cheating called Investigator Interference.  Polypeptides do not form naturally; they hydrolyze.  These scientists started out with polypeptides which are highly improbable and would not survive in nature.  Moreover, if any oxygen were present (as most admit was probably present on the early earth), no amino acids would be formed in the first place.  These scientists also purposely excluded the many destructive molecules that would have been present under natural conditions.  But even if through some miracle they ended up with a pure one-handed solution of polypeptide chains, it would explain nothing of the origin of information and function.  If these scientists really wanted to do a fair experiment, they should keep their guiding hands off the apparatus and let the laws of thermodynamics and probability take their toll.  The results would be depressing.
Next headline on: Origin of Life.

Articles 02/16/2001:  A special focus on Sanctity of Life by Leadership U, with articles on euthanasia, stem-cell research, abortion and related topics.
Next headline on: Politics and Ethics.

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