Comments on: Function, non-function, some function: a brief history of junk DNA.

By: Icke-kodande DNA « Biolog(g)

Icke-kodande DNA « Biolog(g) — Thu, 12 May 2011 19:24:45 +0000

[...] http://www.genomicron.evolverzone.com/2007/06/function-non-function-some-function/ [...]

By: phoboskitty

phoboskitty — Thu, 17 Apr 2008 18:30:00 +0000

about the “amount” of non-coding DNA… and the idea of less or more “complex”

is this tied to Time? like would not a species that has been around for let say 100,000,000 years have more of this than lets say Humans (around 200,000 years old)assuming there is not some environmental disaster or mass extinction

and is the “Junk” the same across a species, like would a Wolf have the same Junk or mostly the same junk as a Basset hound?, or like is the amount of “junk” in the Human Genome, around the same for the Neanderthal Genome? or will you find the same kind of non-coding DNA across a diverse amount of species

By: TR Gregory

TR Gregory — Thu, 14 Jun 2007 15:56:00 +0000

Quite right, although I don't think there is anything inherently anthropocentric in my argument. I only make a connection to humans in this way for two reasons: 1) most of the discussion is about function in the human genome, so even if you manage to show function little by little in our genome and make it to a majority of sequences, you'd have to do that five times over in the onion, and 2) it gets people to think about the issue in a new way because most non-specialists are used to thinking of humans as "complex" in some way.

In the more developed version, I point out that several of the domesticated onion's congeners have much larger genomes, and I have also pointed out that it is equally challenging to find that a pufferfish "needs" (if absolute functionality is expected) only 1/10 as much non-coding DNA as humans.

Humans indeed may have less complex gene regulation. But is it 10 times less complex than a salamander or 10 times more complex than a pufferfish? In any case, the evidence to date points to only a small portion of our own genome being functional in this way, so in that sense a comparison based on regulation is moot.

But yes, let me be clear and agree with Jonathan unambiguously: there is no objective basis for anthropocentrism in discussions about genomic features.

By: Jonathan Badger

Jonathan Badger — Thu, 14 Jun 2007 15:23:00 +0000

Well, while I certainly agree that functionality/adaptive nature shouldn’t be the null hypothesis, I don’t buy the assumption that most non-coding DNA must be non-functional simply because onions have much more non-coding DNA than we do.

For that argument to work, you have to buy into the anthropocentric notion of “less complex” and “more complex” organisms, which you (quite correctly) put in scare quotes earlier in your article. As humbling as it may be, humans may not have the most “complicated” gene regulation.

A better argument (which you use yourself on the linked page) is pointing out that apparently closely related species can have vastly different genome sizes. This brings up the issue without anthropocentric bias.