29
Nov
08

Creationists again…

The fun never ends with many creationist claims. If you’re not familiar with ERVs, LINEs, SINEs, and Retrotransposons, migrate your ass over to wikipedia. I’ve got some fun stuff via the nice ERV lady. Let’s break this down:

Endogenous retroviruses (ERVs) are some of the most cited evidences for evolution.

Uhh, dumbass must not be familiar with the MOST cited evidences for evolution, ERVs aren’t even close, although they do offer supporting evidence. The MOST cited evidence for evolution doesn’t even include genetic studies of thousands upon thousands of species which describe their phylogenies. Most of this DNA evidence was never looking at ERVs, but instead looked at various coding region. Only recently have we began looking at the movements of ERVs and mutations within them, but it’s still work in progress. The MOST cited evidences for evolution comes via the history of animal domestications. These give insights into how animals may be selected for in the wild and how a population may change given certain selective pressures. You wish it was the only piece of evidence for evolution, but wishing for something doesn’t make it so.

They are part of the suite of ‘junk DNA’ that supposedly comprised the vast majority of our DNA. ERVs are said to be parasitic retroviral DNA sequences that infected our genome long ago and have stayed there ever since. These short DNA strands are found throughout the human genome, and make up about 5% of the DNA, or about 10% of the total amount of DNA that is classified as transposable elements (i.e. 50%).

Cute, he calls it “junk DNA.” Does genius not realize DNA sequences aren’t like spam e-mail? If said transposon inserts itself in the promoter region of a gene, that DNA sequence is the new promoter, be it more or less efficient at getting said gene transcribed. These effects can be positive or negative or neutral and may be combinations of positive and negative effects to varying degrees.

However, the term ‘endogenous retrovirus’ is a bit of a misnomer. There are numerous instances where small transposable elements thought to be endogenous retroviruses have been found to have functions, which invalidates the ‘random retrovirus insertion’ claim.

What? Do you know what the word “endogenous” means? It means “arising from within” and as such, “endogenous retrovirus” fits perfectly, it isn’t a misnomer. Also, just because some sequence of DNA is used as a promoter for something invalidates it being randomly inserted how? I just explained that if a transposon plops itself in the location of a promoter and resembles the consensus sequence, it will be used. Sorry to break it to you, but promoters of ERVs being used as promoters for other genes doesn’t invalidate the idea of random integration of ERVs. Random integration would be invalidated if you found a transposon that consistently integrates in only one or two places.

For instance, studies of embryo development in mice suggest that transposable elements (of which ERVs are a subset) control embryo development. Transposable elements seem to be involved in controlling the sequence and level of gene expression during development, by moving to/from the sites of gene control.

OK, first of all, a creationist writes an article misrepresenting research considerably, then you go on to cite the article and not the research? What amazing references! Anyway, activity of certain LTR Class III retrotransposons was useful in mammalian development to allow a genetically distinct organism to develop within the maternal reproductive tract. TEs were not controlling anything; their activity was developmentally regulated; meaning “their activity is induced by various developmental pathways where activation of these transcripts was adapted for embryo development within the uterus.”

Moreover, researchers have recently identified an important function for a large proportion of the human genome that has been labelled as ERVs. They act as promoters, starting transcription at alternative starting points, which enables different RNA transcripts to be formed from the same DNA sequence.

*gag*

Yea, many of them play roles in cancer, too… I guess that’s also somehow what they’re supposed to be doing.

So we’re not just talking about a small scale phenomenon. These ERVs aid transcription in over one fifth of the human genome! ‘These data illustrate the potential of retroviral sequences to regulate human transcription on a large scale consistent with a substantial effect of ERVs on the function and evolution of the human genome.’ This again debunks the idea that 98% of the human genome is junk, and it makes the inserted evolutionary spin look like a tacked-on nod to the evolutionary establishment. These results support the conclusions of the ENCODE project, which found that at least 93% of DNA was transcribed into RNA.

Unfortunately, sometimes that use of ERV promoters means certain sequences are over-expressed leading to diseases. It doesn’t indicate that ERVs are “functional,” it indicates parts of the ERV DNA have been adapted for less deadly roles. Repeating over and over that “junk DNA” isn’t “junk” only demonstrates your lack of understanding the recent advances in genetics. It was called “junk DNA” by the public because it had no known function, now that we understand those functions, no one calls it “junk DNA.” When the term was used to explain genetics to those unfamiliar with genetics, you decide to pounce upon it fifteen years later as evidence that incomplete knowledge was wrong?

Read the rest of the article if you like, it’s all vacuous claims with conclusions, if you continue with the lack of logic, they don’t even understand.

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