I’m engaged in a discussion on Facebook with Fazale Rana of Reason to Believe. The topic is Junk DNA. I just thought I would post it here in case anyone wants to comment here, or even join the discussion there.
I continue to argue that he’s way out over his skis here, on junk DNA in general and on ERVs specifically. The functions that have been documented - co-opted retroviral proteins, LTRs co-opted to regulate human genes - are simply not generalizable to most ERV sequences for two simple reasons: The vast majority of ERVs both 1) completely lack the genes and are either solo or tandem LTRs, and 2) are not under purifying selection, which means they aren’t being maintained as regulatory or anti-retroviral elements.
Every function Fuz (and others) propose for ERVs requires sequences specificity, which means the vast vast majority of them are not doing any of those functions.
Do you read his stuff? Is it the same genteel fictions that he’s been urping up for 17 years?
It’s the same argument advanced by a lot of anti-junk biologists: look, some of these ERVs/pseudogenes/LNCRNAs/etc. are functional, therefore they all are.
And thank you for posting this. I started reading Rana’s article and got a bit confused even in the first paragraphs. For example:
Life scientists continue to identify new functions for so-called junk DNA. Recently, a researcher from the US Centers for Disease Control and Prevention pointed out two overlooked “junk DNA” functions: (1) serving as a nucleoskeleton that establishes the volume of the cell’s nucleus; and (2) acting as a mutational buffer that protects the genome from mutations resulting from transposon and retroviral DNA insertion activity.
How is this news? This is not at all within my fields of training but aren’t both of these “functions” familiar ideas which have been around for a very long time?
Moreover, I don’t see how either of these descriptions defies the concept of “junk.” To consider some analogies, I had a friend who used some busted concrete with the rebar still embedded in it as ballast for his boat. The fact that it had a current function didn’t change the fact that the concrete chunks were basically junk and no longer served their original purpose. Likewise, a faculty colleague used to use an ancient hard-drive platter as a paperweight. It was junk (though old data was still generously recorded on its tracks) but it continued to serve a legitimate function on his piles of paperwork that he didn’t want blowing around when he opened his office window. Why should it surprise anyone when junk proves useful? (Indeed, virtually any “junk” can continue to be useful if you need something to take up space or serve as a paperweight.)
Such results help undermine the argument that junk DNA must be leftovers of evolutionary processes, not the creation of an intentional Designer.
Of course, this is a false dichotomy. Something could be a “leftover” of evolutionary processes while also being something a Designer intended for his creation. (Eroded mountain ranges eventually can become fertile soil by means of geologic and biochemical processes while also being intended by a Designer. Isn’t soil thereby repurposed “junk” and also quite useful?)
Is there something I’m missing here?
That’s bad enough but by itself that’s just hilariously dumb and lazy. I know that lots of uninformed people (including a frustrating number of biologists) are prone to such grade-school-level errors, but that’s not the big lie of design re “junk DNA.”
The more pernicious falsehoods are that biologists “expected” or even predicted vast amounts of “junk DNA” and that this was necessitated by evolutionary theory. Neither is remotely true, and we’re long past the time when the repetition of these lies can be excused.
Well, some population geneticists did expect and predict that, and it’s necessitated by some features of evolutionary theory, e.g. genetic load, the C-value paradox, etc.
BTW, that CDC researcher will be well-known to those of us who have frequented Sandwalk. This is the sort of authority Rana cites to support his beliefs:
Aye, and I’ve discussed this before. Rana and other design propagandists write a fable much different from your account, and they thoroughly and carefully omit the fact that the existence of “junk DNA” was considered nonsensical to some evolutionary thinkers in the pre-genomic era. From Palazzo and Gregory (2014):
In fact, various early commenters considered the notion that large swaths of the genome were nonfunctional to be “repugnant” , , and possible functions were discussed each time a new type of nonprotein-coding sequence was identified (including pseudogenes, transposable elements, satellite DNA, and introns…
But I think my post does need this correction: the biggest lie repeated by Ross and Rana and the minions of the DI is not the one about “junk DNA” being “expected” by evolutionary theory. It’s the one about how evolutionary interpretations of genome sizes and non-coding DNA hindered research. That’s the biggest lie in the collection. I wrote about it a long time ago:
Quite so. I was just pointing out that there was, at various times, considerable disagreement within evolutionary biology on this point, and the battle between the selectionists and the neutralists long predates the genomic era and even the DNA-is-the-genetic-material era.
So it’s not junk because it’s junk.
It also fails the onion test.
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