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Study: Satellite DNA Is Essential and Species-Specific in Drosophila melanogaster


The latest “we thought it was junk but it turned out to be crucial” study comes with the added bonus that the so-called “junk” is also species-specific and taxonomically restricted. The general topic is tandemly repeated satellite DNA in the much-studied fruit fly, Drosophila melanogaster. These satellite DNA regions comprise 15-20 percent of D. melanogaster’s genome, and one of the regions, AAGAG(n), is transcribed across many of D. melanogaster’s cell types.

While evolutionists have hoped and argued that transcription (not to mention mere presence) does not imply function (after all biology is one big hack-job, so RNA polymerase doesn’t always know what it is doing), D. melanogaster is once again not cooperating. Not only is the satellite DNA ubiquitous and widely transcribed, the AAGAG RNA was found to be important for male fertility. Kind of important.

But Wait

It gets worse. Much worse.

Not only is D. melanogaster’s satellite DNA ubiquitous, widely transcribed across many cell types, and of crucial importance, it is species-specific. The levels of AAGAG satellite DNA is orders of magnitude lower in D. simulans and D. sechellia, and nearly absent in other species within the Drosophila genus.

This makes no sense in evolutionary terms. Now we must say that not only does a massive quantity of AAGAG satellite DNA abruptly appear in a particular fly species, but it immediately takes on an absolutely crucial role. A role which, of course, was somehow already fulfilled in the putative evolutionary ancestor.

In other words, the function in question (male fertility) was rumbling along just fine, and then with a new species, and not in many of its sister species, the crucial function was somehow rewired and reassigned to a relatively new, massive, DNA satellite sequence.

Even the Paper Admits

This is absurd. Even the paper admits as much: “Finally, it is worth noting that the expression of simple satellites for essential functions seems incompatible with the fast evolution of satellite DNAs, reflected in dramatic changes in both sequence types and copy numbers across species.”

Ya think? The next step will be for evolutionists to convert this spectacular failure into compelling evidence that evolution can produce DNA that is both (1) species-specific, and (2) functionally essential.

And why is that true? Because, after all, the satellite DNA evolved, of course. And since it is species-specific and essential, we now have evidence evolution can produce such an unexpected outcome.

That’s just good, solid, scientific research.

Photo credit: Käpik [CC BY-SA 4.0], via Wikimedia Commons.

Cross-posted at Darwin’s God.