RE: [asa] How big a deal is homology?

Progressive creationists typically don't permit genetic links between
species whereas creation by evolution does. That's a big difference in
my estimation.

Dick Fischer

Dick Fischer, Genesis Proclaimed Association

Finding Harmony in Bible, Science, and History

 <http://www.genesisproclaimed.org> www.genesisproclaimed.org

-----Original Message-----
From: asa-owner@lists.calvin.edu [mailto:asa-owner@lists.calvin.edu] On
Behalf Of Rich Blinne
Sent: Wednesday, March 28, 2007 11:42 AM
To: David Opderbeck
Cc: Dawsonzhu@aol.com; asa@calvin.edu
Subject: Re: [asa] How big a deal is homology?

On 3/28/07, David Opderbeck <dopderbeck@gmail.com> wrote:

Don't get me wrong, I appreciated Collins' book and admire him, and I'm
very glad he's injecting some new ideas into the coversation and that
publications such as Christianity Today are taking notice. But, I still
think his book was seriously weakened by some of his broader jabs at ID.
In many cases, the TE pointing a finger at ID has three fingers pointing
back at himself. At some point, given an orthodox understanding of
God's sovereignty, it seems to me that the distinction between
"progressive creation" and "creation by evolution" becomes meaningless.

So, given that theology is neutral to progressive creation vs. creation
by evolution, then the answer is determined what does the
non-theological evidence point to and for that it is abundantly on the
latter. God COULD do either. The question is what DID God do. Your
concern about gene to pseudogene transitions only deals with an edge
condition of a larger issue which is known as copy number variation.
Copy number variation is where parts of the genetic code get duplicated
or deleted. The issues being currently pondered look like this question:
If particular genes have a function then what is the "functional"
difference when there exists copy number variation? While copy number
variation is getting lots of play these days the idea has been around
for quite a while. For example, during my literature search I found a
paper on it dating from 1987.This phenomonon appears to make the genetic
differences not only between between species but within species larger
than originally appreciated. The concept of genes as "functional legos"
that gets stacked differently from species to species by the progressive
creationists is thus overly simplistic.

For example,

http://biology.plosjournals.org/perlserv/?request=get-document
<http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1
371/journal.pbio.0020207> &doi=10.1371/journal.pbio.0020207

Given that gene duplication is a major driving force of evolutionary
change and the key mechanism underlying the emergence of new genes and
biological processes, this study sought to use a novel genome-wide
approach to identify genes that have undergone lineage-specific
duplications or contractions [RDB note: these contractions are
apparently what bothers David.] among several hominoid lineages.
Interspecies cDNA array-based comparative genomic hybridization was used
to individually compare copy number variation for 39,711 cDNAs,
representing 29,619 human genes, across five hominoid species, including
human. We identified 1,005 genes, either as isolated genes or in
clusters positionally biased toward rearrangement-prone genomic regions,
that produced relative hybridization signals unique to one or more of
the hominoid lineages. Measured as a function of the evolutionary age of
each lineage, genes showing copy number expansions were most pronounced
in human (134) and include a number of genes thought to be involved in
the structure and function of the brain. This work represents, to our
knowledge, the first genome-wide gene-based survey of gene duplication
across hominoid species. The genes identified here likely represent a
significant majority of the major gene copy number changes that have
occurred over the past 15 million years of human and great ape evolution
and are likely to underlie some of the key phenotypic characteristics
that distinguish these species.

See here for both positive and negative copy number variation amongst
the different great ape species:

http://biology.plosjournals.org/perlserv/?request=slideshow
<http://biology.plosjournals.org/perlserv/?request=slideshow&type=figure
&doi=10.1371/journal.pbio.0020207&id=9002>
&type=figure&doi=10.1371/journal.pbio.0020207&id=9002

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Received on Wed Mar 28 13:06:20 2007