Carnivorous Plant Ejects Junk DNA

sciencehabit writes "The carnivorous humped bladderwort, found on all continents except Antarctica, is a model of ruthless genetic efficiency. Only 3% of this aquatic plant's DNA is not part of a known gene, new research shows. In contrast, only 2% of human DNA is part of a gene. The bladderwort, named for its water-filled bladders that suck in unsuspecting prey, is a relative of the tomato. The finding overturns the notion that this repetitive, non-coding DNA, popularly called 'junk' DNA, is necessary for life."

Comments

No. Bad Conclusion. Bad.

[eldavojohn]

The finding overturns the notion that this repetitive, non-coding DNA, popularly called 'junk' DNA, is necessary for life.

False. Unsurprisingly, nowhere in the paper was this dubious claim even approached. Instead you can find this even in the summary:

However, extreme genome size reductions have been reported in the angiosperm family tree.

Emphasis mine. And then further into the actual paper:

Relaxed selection pressure for unnecessary functions probably led to gene losses, whereas in other cases, gene family expansions may have been promoted by selection. Evidence for localized selection on the U. gibba gene complement, however, does not provide support for the existence of genome-wide selective forces that might favour reduction of nonessential, non-coding DNA.

There would likely be no bladderwort had there been no junk DNA in its ancestral line and other findings point to such noncoded DNA as necessary for evolution.

I believe a more prudent falsifiable hypothesis would run along the lines of (and I'm sorry, I'm only a software developer): Due to relaxed external selective pressures the bladderwort's RNA polymerase has become adept at writing coding errors to the 3% noncoded DNA during replication and this actually still serves a vital function -- especially if the bladderwort is to survive in a much larger window than a few generations.