Carnivorous Bladderwort Plant Stuns Scientists by Having Less DNA But More Genes

A certain carnivorous plant may seem complex, but it has a tiny genome. The carnivorous bladderwort lives in an aquatic environment, has no recognizable roots, has floating, thread-like branches and miniature vacuum pressure traps to capture prey, and now scientists are taking a closer look at its genetic makeup.

While the bladderwort may have a small genome, it still crams in more genes than several well-known plant species, such as grape, coffee or papaya. In fact, the bladderwort has an incredibly compact architecture, which researchers believe results from a history of "rampant" DNA deletion; the plant added and then eliminated genetic material at a very fast pace.

"The story is that we can see that throughout its history, the bladderwort has habitually gained and shed oodles of DNA," said Victor Albert, one of the researchers, in a news release. "With a shrunken genome, we might expect to see what I would call a minimal DNA complement: a plant that has relatively few genes-only the ones needed to make a simple plant. But that's not what we see."

What's interesting is that bladderwort has more genes than some plants with larger genomes. The bladderwort holds roughly 80 million base pairs of DNA, which is six times smaller than the grape's. However, it has 28,500 genes, opposed to 26,300 genes for the grape.

"When you have the kind of rampant DNA deletion that we see in the bladderwort, genes that are less important or redundant are easily lost," said Albert. "The genes that remain-and their functions-are the ones that were able to withstand this deletion pressure, so the selective advantage of having these genes must be pretty high. Accordingly, we found a number of genetic enhancements, like the meat-dissolving enzymes, that make Utricularia distinct from other species."

Most of the DNA that was deleted was so-called "junk DNA" that contains no genes. These findings reveal a bit more about this amazing plant, and shows how its swift gene gain was balanced by equally fast deletion.

The findings are published in the journal Molecular Biology and Evolution.

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