RE: 'Directed' evolution?

Kevin L. O'Brien (klob@lamar.colostate.edu)
Tue, 22 Sep 1998 12:36:13 -0600

That would depend upon what is meant by "added information." Would a
protein with a new function, a function that never existed before, a
function that never could have existed before, be an example of "added
information"? If so, then I can give four examples.

1) Heavy metal toxicity resistance in plants. Before the modern
industrial age there simply wasn't enough lead, cadmium or mercury around
for plants to worry about. Now there are places in the world where the
soil is so contaminated with these and other heavy metals that plants can
die unless protected. Those that can survive had mutations that created
proteins that were able to bind up these heavy metals and sequester them
away from other proteins and the DNA. This function never existed before,
could never exist before, because only recently have plants started
encountering these kinds of metals.

2) Resistance to man-made antibiotics. Man-made antibiotics do not exist
in nature, so bacteria exposed to them can survive only if they experience
mutations that create proteins that either bind up and sequester the
antibiotics or catalytically destroy them. Again these are new functions
that never existed before, could never exist before, because these man-made
antibiotics did not exist before.

3) Resistance to DDT. DDT is a man-made pesticide, yet mosquitoes have an
uncanny ability to produce mutations that protect them. These mutations
produce enzymes that break DDT up into two or more harmless pieces.
Because DDT never existed before this function never existed before, could
never exist before. It only came about after DDT was invented.

4) Nylon digestion. Nylon is a man-made polymer, yet some bacteria are
able to break it down and use it for food. All of these bacteria produce
enzymes that are themselves the result of mutations. In one case the
mutation was a frameshift mutation. This caused the reading frame of the
gene to be shifted by nucleotide, changing all the genes at once. Most of
the time this kind of mutation destroys an active gene, but in this case it
created a new gene that produced an enzyme which was able to break the
nylon polymer bond. Since nylon never existed before, this function never
existed before, could never exist before, so it must be new information.

A reasonable objection would be to claim that these mutations alter
proteins that already exist. We know that in the case of the nylon enzyme
this is not true, but that's why I focused on new *functions*, not new
proteins. If an existing protein is modified to perform a whole new
function, one that never existed before, one that could never exist before,
this is new information, even if the change in the protein is not.

Kevin L. O'Brien
klob@lamar.colostate.edu

-----Original Message-----
From: Ron Chitwood [SMTP:chitw@flash.net]
Sent: Tuesday, September 22, 1998 10:40 AM
To: evolution@calvin.edu; Arthur V. Chadwick
Subject: Re: 'Directed' evolution?

The book 'Not by Chance" by Spetner, I think is must reading. Sometimes
its above my head as someone unconversant with microbiology but the theme
is quite clear. Randomness simply cannot explain the information increase
over the supposed eons of evolution. To quote one passage, pp 131.
"...Among all the mutations that have been studied, there aren't any known,
clear, examples of a mutation that has added information."

Arthur, I heartily 2nd the motion that it should be read.

Ye shall know the Truth, and the Truth
shall make you free. John 8:32
Ron Chitwood
chitw@flash.net

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