Some more junk DNA shown to have function

Here's another study that's going to get creationist arms in the air. It shows a function for some "junk DNA" - DNA that does not serve any function for the developing organisms - namely in coding for micropeptides (very short proteins), which have now been shown to have a regulatory function in Drosophila. The first lines of the abstract reads

A substantial proportion of eukaryotic transcripts are considered to be noncoding RNAs because they contain only short open reading frames (sORFs). Recent findings suggest, however, that some sORFs encode small bioactive peptides. Here, we show that peptides of 11 to 32 amino acids encoded by the polished rice (pri) sORF gene control epidermal differentiation in Drosophila by modifying the transcription factor Shavenbaby (Svb). [Emphasis added.]

It's actually quite interesting, the finding that very short proteins have a regulatory effect on gene expression, much the same way that very short RNA molecules do (microRNA). But it doesn't mean that all DNA has a function. Just some more than what we previously thought. Some.

Of course, the researchers have not shown that all DNA has a function, which is nevertheless how this is going to be presented, tacitly. For example:

But according to David Stern, a Princeton professor in the Department of Ecology and Evolutionary Biology, scientists increasingly believe "junk DNA" is crucial for turning the information encoded in genes into useful products.

*Multisigh*

For those who think that no DNA is without function, please consider The Onion Test.

The onion test is a simple reality check for anyone who thinks they have come up with a universal function for non-coding DNA. Whatever your proposed function, ask yourself this question: Can I explain why an onion needs about five times more non-coding DNA for this function than a human?

An inordinate fondness for beetles, and also for very large and redundant genomes, perhaps?

Reference:
Kondo, T., Plaza, S., Zanet, J., Benrabah, E., Valenti, P., Hashimoto, Y., Kobayashi, S., Payre, F., & Kageyama, Y. (2010). Small Peptides Switch the Transcriptional Activity of Shavenbaby During Drosophila Embryogenesis Science, 329 (5989), 336-339 DOI: 10.1126/science.1188158

---

Update 7/19:

This table shows the genome sizes for 30 species of onions. They all have huge genomes (from Evolution of genome size across some cultivated Allium species, A. Ricroch, R. Yockteng, S.C. Brown, and S. Nadot, Genome 48: 511–520, 2005).


Click for larger image.