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Carnivorous bladderwort genome reveals purpose of junk DNA: nothing

The newly mapped genome of a carnivorous underwater bladderwort plant may provide new clues into the existence of so-called "junk DNA," clues that point towards a surprising finding: junk DNA is not necessary for complex life.

The vast majority of humans' DNA is noncoding, in other words it doesn't code for proteins and serves no discernible function. Scientists have long argued over whether is is truly "junk" or has some purpose not yet known.

But in a paper published in Nature on Sunday, an international team of scientists has shown that the genome of Utricularia gibba, the highly complex carnivorous bladderwort plant, is only 3 per cent junk. The plant has deleted almost all of its noncoding DNA over the course of many generations.

The team argues that this shows that having huge amounts of junk DNA, as humans have, doesn't serve an evolutionary benefit. Some organisms may go about deleting their junk DNA, and others may beef up their junk DNA, depending on some internal bias. 

The bladderwort plant lives in freshwater ecosystems, and operates by pumping water from tiny "bladders" on its body, sucking prey in and the water returns. The plant has as many genes as plants like tomatoes or grapes, according to a press release announcing the findings, but the bladderwort's genome is much tinier on account of its tendency to delete its junk DNA.

"What that says is that you can have a perfectly good multicellular plant with lots of different cells, organs, tissue types and flowers, and you can do it without the junk. Junk is not needed," said Victor Albert, a University of Buffalo biological sciences professor, in a press release.

The study was led by Albert and Luis Herrera-Estrella, Director of LANGEBIO in Mexico, and has contributions from researchers in Singapore, Spain, China, and Germany.


Kate Allen is the Star's science and technology reporter. Find her on Twitter at @katecallen. 


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Interesting research, but isn't it too soon to make a blanket statement about ALL so-called 'junk DNA' based upon one plant?

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