Non-coding ultraconserved DNA is, well, preserved in animals

It seems redundant to say that ultraconserved non-coding DNA is conserved or preserved, but it is two different types of “conservation” that are being discussed.  The quandary has been that stretches of non-coding DNA are extremely faithfully copied–which implies that natural selection is preserving the sequences–while taking these stretches out of lab animals has no discernable effect on the animals lacking these ultraconserved regions.

Then the question is, are lab animals really an appropriate test (members of captive populations typically survive a good deal less well in the wild than do their wild counterparts–including where nurture is not a factor) of the value of these ultraconserved regions, and how would one test to see if these stretches of DNA are valuable to wild populations?

The answer, or at least an answer, is to find out if natural deletions of these regions are well-tolerated by wild populations.  It turns out that deletions of the ultraconserved regions in question are only 1/300th as likely to be tolerated by wild populations as are deletions of neutral, non-conserved stretches (presumed to be actually useless “junk DNA”) of non-coding DNA.  So it seems that the ultraconserved DNA does have a function after all, although we still do not know what it is.

Read more about it here.

It’s not surprising, of course, that there is an evolutionary basis for the ultraconserved DNA.  Whether even a 300X better retention of this DNA actually tells us why it is that these chunks of DNA are conserved rather better than coding DNA usually is, seems in doubt, at least to me.  It appears that a lot remains to be learned about these parts of genomes, especially how they actually do enhance survival of wild-type organisms.

There have been a few cases where IDists have tried to make something of the fact that ultraconserved DNA, like on Uncommon Descent. On the whole, though, many seemed not too eager to make much of it, knowing that future research could come back to bite them. After all, there is a great deal not yet understood about DNA and its regulation, and lab animals are not really very useful for testing subtle effects on wild populations. Still, it’s gratifying to see Uncommon Descent shown to be wrong yet again, no matter how commonly this occurs.

Even more so, it’s just good to see how research once again uses evolutionary understanding both to find problems, and then to find the solutions to those problems.  And exactly what has ID been doing while scientists were doing research into evolution, in this and a myriad of other areas?

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