Science Talk

Gabriel · Guest

"Many evolutionists state that the bacteria are experiencing
“adaptive evolution.” However, this is not evolution but rather
adaptation. Molecules-to-man evolution requires an increase in
information and functional systems. Instead, these bacteria are
likely experiencing a loss of information and functional systems
as has been observed in other mutant bacteria in Lenski’s lab.
While these changes are beneficial in the lab environment, it is
does not lead to a net gain that move bacteria in an upward
evolutionary direction."

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http://www.answersingenesis.org/articles/aid/v2/n1/a-poke-in-the-eye

Jerry Coyne, evolutionary biologist at the University of Chicago,
thinks that Richard Lenski’s recently published research on
citrate utilization by Escherichia coli1 is just that—“another
poke in the eye for anti-evolutionists.”2 He goes on to say, “The
thing I like most is it says you can get these complex traits
evolving by a combination of unlikely events. That’s just what
creationists say can’t happen.”2 I agree that creationists say
that cannot happen; however, Lenski’s research does not show that
it did! Instead Lenski’s research is another “feather in the cap”
for creationists and further demolishes evolutionary ideas that
complex traits can arise by random mutations.

Lenski’s 20-Year experiment
In 1988 Richard Lenski, an evolutionary biologist at Michigan
State University, began culturing 12 identical lines of E. coli.
Over 44,000 generations and 20 years later, the experiment
continues. The bacteria are grown in medium, which has a small
amount of glucose (a primary carbon source for E. coli) and
abundant citrate (a carbon source not utilized by E. coli). Every
500 generations, his lab takes samples of the bacteria, which in
essence produces a “fossil record” of the different lines. Lenski
has observed many changes in the E. coli as they adapt to the
culture conditions in his lab. While the fitness of the bacteria
has increased (as compared to the starting bacteria), it has come
at a cost. For example, all the lines have lost the ability to
catabolize ribose (a sugar).3 Some lines have lost the ability to
repair DNA.4 These bacteria may indeed be more fit in a lab
setting, but if put in competition with their wild-type (normal)
counterparts in a natural setting, they would not stand a chance.
[A detailed analysis of Lenski’s work from a creationist
perspective will be presented at the International Conference on
Creationism (ICC) 2008 and in a paper published in the ICC
Proceedings5].

Many evolutionists state that the bacteria are experiencing
“adaptive evolution.” However, this is not evolution but rather
adaptation. Molecules-to-man evolution requires an increase in
information and functional systems. Instead, these bacteria are
likely experiencing a loss of information and functional systems
as has been observed in other mutant bacteria in Lenski’s lab.
While these changes are beneficial in the lab environment, it is
does not lead to a net gain that move bacteria in an upward
evolutionary direction.

The Magic Generation: 31,500
Lenski’s lab discovered that at generation 31,500, one line of E.
coli could utilize citrate (Cit+). As mentioned previously, E.
coli are not usually able to utilize citrate (Cit-), and this
fact is typically used as diagnostic identification of E. coli. A
New Scientist writer proclaims, “A major innovation has unfurled
right in front of researchers’ eyes. It’s the first time
evolution has been caught in the act of making such a rare and
complex new trait.”2 However, as we will see, this is a gross
overstatement in regards to what actually occurred.

Previous research has shown that wild-type E. coli can utilize
citrate when oxygen levels are low.6 Under these conditions,
citrate is taken into the cell and used in a fermentation
pathway. The gene (citT) in E. coli is believed to encode a
citrate transporter (a protein which transports citrate into the
cell).6 When oxygen levels are high, it is thought that the
citrate transporter does not function or is not produced (even
though they still possess the enzymes necessary to utilize
citrate). Thus, wild-type E. coli already have the ability to
transport citrate into the cell and utilize it—so much for the
idea of a “major innovation” and “evolution . . . making a rare
and complex new trait”! Other labs have also produced Cit+ E.
coli and speculated that mutation(s) in citT (or its regulators)
allow the citrate transporter to function or be produced under
high oxygen levels.6, 7 These types of changes are very
consistent with the creation model (see below), but cannot serve
as a means for evolution.

Lenski’s lab has not yet identified the genetic alterations of
the Cit+ E. coli line, but he believes that there are multiple
mutations involved. Studies of the “fossil record” of this line
indicate that one or more mutations occurred around generation
20,000 which he terms “potentiating” mutations that were
necessary before additional mutations around generation 31,500
led to Cit+ cells. Lenski thinks that the mutations may have
activated a “cryptic” transporter (a once functional transporter
that has been damaged due to the accumulation of mutations) that
can now transport citrate. However, he states, “A more likely
possibility, in our view, is that an existing transporter has
been coopted [sic] for citrate transport under oxic [high oxygen
levels] conditions.”1 He believes this could be the same citrate
transporter (citT) used in low oxygen conditions (inferring a
loss of regulation) or a transporter for another substrate that
has been modified to transport citrate (inferring a loss of
specificity).

Lenski states (based on calculated mutation rates in E. coli),
“It is clearly very difficult for E. coli to evolve this
function. In fact, the mutation rate of the ancestral strain from
Cit- to Cit+ is immeasurably low . . . .”1 If developing the
ability to utilize citrate under certain conditions using random
mutations of a pre-existing citrate utilization system is so
rare, then how even more improbable is it to believe that these
same random mutations can lead to completely new information and
functional systems that allow dinosaurs to turn into birds!
Lenski’s work shows a clear case of adaptation and not evolution.

A Creationist Perspective
Mutations which lead to adaptation, termed adaptive mutations,
can readily fit within a creation model where adaptive mechanisms
are a designed feature of bacteria allowing them to survive in a
fallen world.8 Since E. coli already possess the ability to
transport and utilize citrate under certain conditions, it is
conceivable that they could adapt and gain the ability to utilize
citrate under broader conditions. This does not require the
addition of new genetic information or functional systems (there
are no known “additive” mechanisms). Instead degenerative events
are likely to have occurred resulting in the loss of regulation
and/or specificity. It is possible that the first mutations or
potentiating mutations (at generation 20,000) were either
slightly beneficial or neutral in their effect.

Given the selective pressure exerted by the media of a limited
carbon source (glucose) but abundant alternative carbon source
(citrate), the cells with slightly beneficial mutations would be
selected for and increase in the population. Alternatively, if
the mutational effects were neutral the cells with these
mutations might remain in the population just by chance, since
they would not be selected for or against. Around generation
31,500 additional mutations enabled the cells to utilize citrate
and grow more rapidly than cells without the adaptive mutations.
Adaptive mechanisms in bacteria work by altering currently
existing genetic information or functional systems to make the
bacteria more suitable for a particular environment. Further
understanding of Lenski’s research is valuable for development of
a creation model for adaptation of bacterial populations in
response to the adverse environmental conditions in a post-Fall,
post-Flood world.

Conclusion
It is interesting that in spite of the clear evidence for the
adaptation of E. coli, Lenski refers to his findings as evidence
for bacteria developing a “key innovation” and a “new function”
and a “fascinating case of evolution in action.”1 Obviously,
presuppositions (human reason vs. God’s Word) play a major role
in interpreting the evidence. Richard Lenski and I are looking at
the same evidence but drawing different conclusions based on our
source of truth—man’s ideas or God’s ideas. It is only possible
to obtain truth about the past if we start with the only source
of absolute truth in the present—the inerrant Word of God.

Zachary Blount, et al., “Historical Contingency and the Evolution
of a Key Innovation in an Experimental Population of Escherichia
coli,” PNAS 105 no. 23 (2008): 7899–7906. Back (1) Back (2) Back
(3) Back (4)
Bob Holmes, “Bacteria Make Major Evolutionary Shift in the Lab,”
New Scientist, June 9, 2008. Back (1) Back (2) Back (3)
Vaughn Cooper, et al., “Mechanisms Causing Rapid and Parallel
Losses of Ribose Catabolism in Evolving Populations of
Escherichia coli B,” Journal of Bacteriology 183 no. 9 (2001):
2834–2841. Back
Paul Sniegowski, et al., “Evolution of High Mutation Rates in
Experimental Populations of Escherichia coli,” Nature 387 (1997):
703–705. Back
Kevin Anderson and Georgia Purdom, “A Creationist Perspective of
Beneficial Mutations in Bacteria,” in A.A. Snelling, (Ed.),
Proceedings of the Sixth International Conference on Creationism
(2008): 73–86, Pittsburgh, PA: Creation Science Fellowship &
Dallas, TX: Institute for Creation Research. In press. Back
Klaas Pos, et al., “The Escherichia coil Citrate Carrier citT: A
Member of a Novel Eubacterial Transporter Family Related to the
2-oxoglutarate/malate Translocator from Spinach Chloroplasts,”
Journal of Bacteriology 180 no. 16 (1998): 4160–4165. Back (1)
Back (2) Back (3)
Barry Hall, “Chromosomal Mutation for Citrate Utilization by
Escherichia coli K–12,” Journal of Bacteriology 151 no. 1 (1982):
269–273. Back
Georgia Purdom and Joseph Francis, “Proceedings of the Microbe
Forum, June 2007,” Answers Research Journal 1 (2008): 1–6. Back

Ken · Guest

So...........what else is new?

Thurisaz the Einherjer · Guest

Morontheist babbliel:

John Baker · Guest

On Wed, 02 Jul 2008 12:03:55 -0400, Gabriel
<gabriel_baptist@hotmail.com> wrote:

Yet another example of Gabriel's ignorance and dishonesty.

Dave Oldridge · Guest

Gabriel <gabriel_baptist@hotmail.com> wrote in
news:vg9n64ho3p0padlk3jdgqdknb8545d8kt2@4ax.com: