Sojourner553

If humans are made "in the image of God" then why do our genes look like a disorganized mishmash of instructions? More precisely, why is 95-98% of the genetic information contained in our genes JUNK??

In case you need a general background:
The Genome Project (which has completed a massive computerized genetic database of all the base pairs of DNA in human chromosomes), has shown that only about 2-5 percent of human DNA is composed of genes. (Genes contain the instructions to make proteins). The rest of the 95-98% of genetic material is regulatory sequences, old nonfunctioning genes or most common of all: non-coding "junk".

Sometimes the genes are not contiguous - but stop and start amid junk
genetic base pair sequences between them (creating a challenge to detect them at all even using super computers.) Even more interestingly: Large stretches of the human genome show sections that look as if viruses were incorporated into them-- probably millions of years ago through infections. Hundreds of genes (encoding at least 223 proteins) appear to be identical to those of bacteria. It has been estimated that roughly 50% of the number of genes in humans is identical to those in yeast. (Henry Gee, "A Journey into the Genome: What's There", Nature News Service/Macmillan Magazine LTD. February 12, 2001)

<a href="http://mac-2001.com/philo/crit/SCIENCE.TXT" target="_blank">http://mac-2001.com/philo/crit/SCIENCE.TXT</a>

<a href="http://mac-2001.com/philo/crit/index.html" target="_blank">http://mac-2001.com/philo/crit/index.html</a>

[ March 16, 2002: Message edited by: Sojourner553 ]</p>

lpetrich

I've thought of the mutagen-sink hypothesis for the toleration of the existence of junk DNA; according to this hypothesis, this extra DNA reacts with various mutagens, consuming them.

I'm sure that some professional geneticist has already thought of that hypothesis; has it been discussed in the literature? I wonder what keywords would be useful in searching for discussions of this hypothesis.

Incorporated viruses are another bit of evidence for evolution; one can make family trees by seeing which viruses are present in various genomes. And yes, one does get reasonable family trees with that method.

DNAunion

DNAunion: The similarities between organisms is incredible.

I was not always convinced that all animals had evolved from "a common lower life form", but then I started posting on the internet. I found several things out.

1) While trying to show someone wrong when he said that genes for the ATP synthase had to all be arranged together in single physical group (those from ARN, no this is not Wolf - it was someone from a year or two before), I found what was a surprising result, at least to me. I found a site that listed the mitochondrial genome for hundreds of animals, representing all various types. And there were sets of genes - whose proteins serve various cellular functions - that were found in virtually all of those mitochondrial genomes. Furthermore, although the ATP synthase has something like 8 genes in all, the mitochondria of virtually all of the animals had only a subset consisting of 2 or 3, and it was always the same 2 or 3 in all of them.

2) While looking into eye evolution, I found all kinds of references (dating from about 1995 on) that showed many conserved genes/proteins involved in eye development, in organisms as distantly related as humans, mice, squids, fruit flies, nematodes, etc.

3) I just started a post here about eukaryotic cell division. I spent an hour or so doing some quick abstract searches and found several kinds of genes/proteins that are highly conserved from yeasts to humans.

To me, all of this argues strongly for common descent. I can personally no longer doubt that all animals share a common ancestor.

And then there is human evolution. The most impressive genetic evidence I have heard in support of it concerns the fusion of two "chimp" chromosomes into a single human chromosome (humans have 23 pairs of chromosomes while chimpanzees have 24 - and yes, I know that humans did not evolve from chimps!). I remember reading that it was actually determined - and confirmed - which human gene was the result of the fusion.

Of course, there are other reasons to accept that all animals - including humans - evolved from a common ancestor. But I am sure the "Infidels" here already knew that.

[ March 16, 2002: Message edited by: DNAunion ]</p>

three4jump

That "junk" DNA is not junk at all. God included it to send us his wisdom, encoded in DNA. He made it a puzzle, so that only when we were wise enough to figure out the puzzle would we gain access to his wisdom. When we decode the junk DNA, we will understand the true majesty of God as revealed in His secret code.

Orpheous99

Well, the excuse which theists and cretinists give is that it is our fault, because of the so-called Fall. That god made Adam and Eve perfect in everyway, but because of our so-called sins we have degenerated into what we are now. Of course you must know that this belief is nothing but nonsense.

Megatron

42.

excreationist

Well I read a book a while ago that was written in the 1960's. It talked about Down's Syndrome being linked to orangutans. I think it said that lots of our DNA is just "turned off" and in the case of Down's Syndrome, many things happen that make them like orangutans. I think it is called "retrograde" or something.
It makes sense though... it is far more likely that a mutation would just turn off a trait than to neatly delete every bit of it out of the DNA.

MrDarwin

I tend to agree with the IDers (and creationists--shudder!) who say that we don't know for a fact that it's "junk". At the very least, evolutionary biologists should be cautious about labeling it as such. We certainly have to ask why there is so much of it--is it truly immune to selective pressure, or is there actually some advantage to having it, that we just haven't discovered yet? Either way, why do some species have so much of it, and others so little? We really don't know for certain.

Kevin Dorner

Down's Syndrome is a chromosomal aberration where the individual has two copies of chromosome 21 (so has 47 chromosomes instead of 46.) It's caused by an error in meiosis, cell division that produces sex cells with haploid (half the regular diploid number, 46 in humans) of chromosomes.

It doesn't have anything to do with orangutans as far as I know (might be that it's an old book.) Similarity in features may not be indicative of similarity in origin.

[ March 17, 2002: Message edited by: Kevin Dorner ]</p>

pangloss

'Junk DNA' having a function is hardly an IDer/creationist proposition. IUt has been known for some time that noncoding DNA can serve regulatory and structural functions.

It is also true, however, that this DNA can accommodate relatively large changes and impart no detriment onto the organism. Look at any large scale DNA sequence alignment, and this is all too clear.