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  Topic: "Junk" DNA, Towards a FAQ on "Junk" DNA< Next Oldest | Next Newest >  

Posts: 319
Joined: May 2002

(Permalink) Posted: Aug. 14 2003,15:41   

Casey Luskin writes:
Link To ID vs Evolution Predictions


4. Genetic Code
Ev: The genetic code will NOT contain much discarded genetic baggage code or functionless "junk DNA."
ID: The genetic code will contain much discarded genetic baggage code or functionless "junk DNA."
'Fact': Increased knowledge of genetices has created a strong trend towards functionality for "junk-DNA"; examples of DNA of unknown function persist, but function can be expected or explained under a design pardigm.

"Junk" DNA;t=35

The basic observation supporting the 'junk DNA' inference is not pseudogenes -- these are a small fraction of noncoding DNA.  The basic observation is that closely-related critters can have widely-varying amounts of non-coding DNA with no apparent ill-effects.


The C-value paradox emerged from among the first applications of spectrophotometric analysis of nuclear DNA content1. The haploid DNA content of eukaryotic organisms ranges over a factor of 80,000. Some of the largest genomes are found among the lowliest of eukaryotes, such as the amoebae, and some of the smallest genomes are found among organisms with complex developmental and behavioural repertoires, such as Drosophila melanogaster.

Charlie d explains it quite well here:


Ironically, the anti-ID letter the DI complains about led me to read an article by a German biologist, apparently an ID sympathizer. Inexplicably, it was published in the prestigious, by-invitation-only Annual Review in Genetics - perhaps because it contained actual information (along with many unsupported and overextended interpretations, but that's just my opinion), and not just a pointless, self-defeating whine like Behe's letter.

Anyway, that paper happens to cite an interesting piece of data that I was unaware of, and which significantly undermines Behe's entire argument that the attribution of lack of function to non-genic DNA is based only on a negative argument (there are many more lines of evidence, of course, but I thought this was nice, especially given the coincidence about the sources).

The data is as follows. These guys (Muntiacus reevesi):

and this (M. muntjak):

are almost identical, they live in very similar environments in Southern China vs. India/South Asia/Indonesia, and just happened to be classified as differnet species because they do not interbreed. The major difference between them is that one has 46 chromosomes and the other 6/7, and one has 20% less DNA than the other, entirely ascribable to the reduction of various kind of non-genic, repetitive elements (ref here.

Go figure: a 20% DNA content difference between practically identical vertebrates (by comparison, remember chimps and humans differ by a few % at most). Gee, I wonder why biologists tend to conclude that most non-genic DNA has no significant function. Must be all that "negative argumentation", indeed.

Until IDists start talking about these kinds of facts they aren't even in the ballpark regarding 'junk DNA'.

  3 replies since April 30 2003,18:28 < Next Oldest | Next Newest >  


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