Increasing information cont. (was: Re: Dawkins' video

Mon, 8 Jun 1998 11:40:19 -0500


I would like to expand for a moment on my previous message. I gave an
example of how organisms can dramatically increase their complexity
essentially through incorporation of other organisms as part of themselves.
The transfer and capture of genetic information by one organism by another
is, I think, a vastly underestimated and under appreciated evolutionary

I believe that biology is only at the cusp of a new age that will see
advances as great or greater than the last 10 years with the advent of
molecular biology (PCR etc..). The tool of this new age will be high
throughput DNA sequencing that will allow whole genome comparisons.
Although DNA sequencing is a very common tool today it is very slow going
when one considers the amount of effort needed to sequence a whole genome
such as in the human genome project. Recently there have been reports of
potential new methods of sequencing DNA that could speed the process up 1000
to 10,000 fold allowing millions of base pairs to be sequenced in a single
lab in a single day rather than the present 10ss of thousands per day. This
means that 10 years from now we may be able to do whole genome comparisons
of organisms. One thing I am sure of is that the availability of such data
will have a profound effect on how we view genomic evolution. You may look
at this as an opportunity to dispell much of the current molecular
evolutionary dogma or as opportunities solve many of the questions still
with respect to molecular evolution. Either way I think that our
understanding of molecular evolution is should be thought of as being in its

So for example we have seen a recent example of one person claiming that the
non-universality of the genetic code proves evolution wrong but really this
was a very premature judgement since so little work had been done to examine
any mechanism that might be responsible for changes in codon assignment. In
only the past 6 months no fewer than 5 papers have addressed the issue and
one paper I just came across last week provides a real evidence to support a
primary prediction made by one prominent theory regarding changes in codon
assignment (When I time I will write a short summary of the paper). This is
an active area of research and a true assessment surely awaits a much
broader survey of organisms and much much larger data set of RNA, DNA and
protein sequences.

Let me make one prediction:

Genomic surveys of diverse organisms will yield much higher percentages of
"foreign" DNA in each genome that is currently known. By this I mean I will
not be surprised (even expect) plant genomes to yield fungal DNA genes,
animals genomes to yield portions of DNA from all kingdoms etc...
Some examples are already well known and are usually attributed to
viral mediated transfer. But I think we will see many many more
examples many of which will have greater significance than the seemingly
random instances of viral mediated transfer.

I like to think of molecular evolutionary studies as being at the level of
understanding that Mendel had of genetics. Sure he had real insight and
much of what he found was reflective of reality and can be used. But he
didn't know about gene linkage and he certainly couldn't have understood
uniparental genetic inheritance such as the mitochondrial and chloroplast
genomes. We do a decent job of comparing simple systems such as the
evolution of single copy genes such as those in the chloroplast and
mitochondrial genomes (e.g. all the molecular phylogenies). But we are only
beginning to understand how genes are posttranscriptionally altered by RNA
editing, how RNAs can be reincorporated into the genome and what effects
that has had on phylogenetic analysis, how genes are transferred from one
organisms to another, how whole genomes may be combined (e.g. my last post).
The list goes on and on. I guess this is why I find it difficult to be
amazed by Behe's examples of irreducible complexity since I don't feel there
is really enough known to truly address the question.

Just my two cents worth today. Somewhat exagerated I am sure.

Joel Duff

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