Micheal Denton explains it in Nature's Destiny on page 289.
If it is true that a vast amount of DNA in higher organisms is in fact junk, then this would indeed pose a very serous challenge to the idea of directed evolution or any teleological model of evolution. Junk DNA and directed evolution are in the end incompatible concepts. Only if the junk DNA contained information specifying for future evolutionary events, when it would not in a strict sense be junk in any case, could the finding be reconciled with a teleological model of evolution. Indeed, if it were true that the genomes of higher organisms contained vast quantities of junk, then the whole argument of this book would collapse. On any teleological model of evolution, most, perhaps all, the DNA in the genomes of higher organisms should have some functions.Sorry Michael, it is true. The genomes of many complex multicellular organisms have vast quantities of DNA that serves no purpose. It's junk. The whole argument of your book just collapsed, as did any argument for intelligent design.
The fact of junk DNA disproves intelligent design and discredits strict Darwinism as well. The IDiots lose twice. Their strawman version of evolutionary biology is wrong and so is design by God.
I know this comes as a great surprise but I actually have a serious question, and it deals with junk.
ReplyDeleteSpecifically, what would be the advantage of dealing with junk? Or, what is the most efficient way to deal with junk?
Using my house as an example it takes quite a lot of energy to deal with junk, and to some extent it's easier (and not a problem) to let a certain amount of junk accumulate.
As a programmer I found it easier to "wall off" code rather than clean it up because I never knew if I'd need it again. I'm not sure that's a great analogy, but there should be a correlation between junk and the path of least resistance.
What the fuck is a higher organism? There are organisms from every taxon that contain non-functional DNA sequences.
ReplyDeleteIn reply to Bill, it takes natural selection to rid a genome of useless DNA. For example, it costs energy to copy each nucleotide during cellular replication, so any extra sequence imposes a fitness cost on its carrier. But that selection is fairly weak.
One of the central tenets of population genetics is that the ability of natural selection to remove/fix an allele depends on the cost/advantage of that allele and the population size of the species Natural selection is more likely to act on alleles with larger coefficients of selection and species with larger population sizes. Therefore, taxa with large population sizes have less junk DNA, and vice versa.
Natural selection is not forward looking -- it can't say "I won't get rid of this because I never know when I may need it".
I once tried to educate a fellow student about the existence of endogenous retroviruses as an example of junk DNA. I was quick to point out to him that this does not automatically preclude divine intervention in matters biological, only that it necessarily follows, assuming there is just one deity, that the He must enjoy littering our genome with itsy bitsy virus chunks.
ReplyDeleteMalevolent Design, perhaps?
I second Bill's question. Is it the case that junk DNA is known to be "junk" or is it more accurate to say we don't know if it has a use?
ReplyDeleteAndyS, check out the research done on Frankenviruses. Yes, some of the DNA in ourselves is 100% junk.
ReplyDeleteAndys asks,
ReplyDeleteI second Bill's question. Is it the case that junk DNA is known to be "junk" or is it more accurate to say we don't know if it has a use?
It's more accurate to say that it's junk. We know that neither the sequence or the amount at a specific location is conserved. This means that it is not under selective pressure.
In some cases, such as pseudogenes or degenerative SINES, we are on pretty solid ground since we can identify previous functions that have been lost.
There's a myth out there that molecular biologists are really stupid. According to the myth, they call it "junk" when what they really mean is that they haven't a clue what the DNA really does. I can assure you that (most) molecular biologists are not that stupid. When we say "junk" that's a conclusion based on evidence and not ignorance. We leave it to the IDiots to base their conclusions on ignorance.
(This does not mean that we are absolutely confident that every little bit of DNA currently labelled as junk will never be shown to have a function. That's not what we're saying. We're saying that we have confidence, based on evidence, that a large percentage of junk DNA really is junk.)
One would have to be very careful about this thread. First, insisting on a "negative evidence" (that there is NO function to 98.7% of human DNA) is such a nonsense, that even Larry Moran admits that only a "large percentage" looks like junk (for those who don't want to research it).
ReplyDeleteThus, there is no "case closed", see the news column at http://www.junkdna.com/new_citations.html
Self-contradition of "mostly junk, but we really don't know" aside, a fervently negative attitude may cost the lives of hundreds of millions, suffering from "junk DNA diseases"; see http://www.junkdna.com/junkdna_diseases.html
Some may only wish to read just some headlines from the compilation of diseases that most likely don't originate from "walled off old code".
A much more modern (one would say, PostModern) view e.g. on "non-coding microRNA" is that it appears that they play major role in regulation (suppression) of tumors:
"It's a revolution in how we understand the genome and how the cell functions," says MIT Nobel laureate Phillip Sharp. "There's a whole new frontier there." Sharp and a few microRNA researchers have founded Alnylam Pharmaceuticals to invent RNA-based drugs to treat Parkinson's, cystic fibrosis and spinal injury. The firm has development deals with Merck and Novartis, and such rivals as San Francisco's Sirna Therapeutics are in pursuit."
The misnomer "Junk" DNA already set back research for too long. Instead of insisting on an obviously untenable notion on any idelogical basis, scientist should better focus on researching the 98.7% of human DNA for practical purposes, e.g. that lives of millions should be saved from dreaded diseases such as Alzheimer's or Parkinson's that at this point are unlikely to be caused by "genes" - looks like there root cause lies in the "Junk".
Those suffering with cancer probably don't appreciate further delays, especially if some would like to enforce it for reasons of ideology.
pellionisz_at_junkdna.com
I completely disagree here!
ReplyDeleteLabelling DNA as junk doesn't mean it doesn't have any function or it never had any function in past(vestigial organs)! It's simple we don't understand it's purpose yet! In science , there is no such absolute truth, each and every finding is relative!
So, your statement "The genomes of many complex multicellular organisms have vast quantities of DNA that serves no purpose" is downright buffonery!
anonymous says,
ReplyDeleteSo, your statement "The genomes of many complex multicellular organisms have vast quantities of DNA that serves no purpose" is downright buffonery!
Nonsense.
We have plenty of evidence to support the statement and, in addition, it's consistent with a large amount of indirect evidence and theoretical calculations.
Everything in science is provisional but that does not mean we have to behave like a post-modernist and avoid making any truth claims at all.
Laurence A. Moran: Now that science is beginning to show that your presuppositions were wrong, I think you should apologize for calling others who questioned your assumptions "idiots".
ReplyDeletehttp://www.nytimes.com/2012/09/06/science/far-from-junk-dna-dark-matter-proves-crucial-to-health.html?_r=2&nl=todaysheadlines&emc=edit_th_20120906
Dr. Larry, I say the Bible is true with the same confidence you have in junk DNA being junk and disproving intelligence design.
ReplyDeleteI cannot prove to you that the Bible is true, it talks about eternal matters beyond the ability of human hands to unveil, beyond human minds can comprehend and seek out. You'd have to read it and come to your own conclusions.
But I would say God loved you and sent Jesus to die for your sins and will save you from a guilty conscious and the coming wrath of God if you believe in him.