Aquatic plant has tiny genome but lots and lots of genes

Bladderworts are a genus of carnivorous plants that prefer freshwater environs or very wet soils. And as a new study finds, at least one bladderwort variety -- in terms of genomics, anyways -- does more with less.
Researchers at the University of Buffalo recently sequenced the genome of Utricularia gibba, one of the most common types of bladderworts called humped or floating bladderwort. Despite its many unique biological features, the quirky aquatic plant has a remarkably short genome.
Inside that short genome are the genetic sequences that enable its odd characteristics. Floating bladderwort forgoes roots, traps prey with vacuum pressure, sprouts small thread-like branches, puts off beautiful yellow flowers and does it all while thriving in aquatic environment.
As the bladderwort's odd lifestyle suggests -- and as the new analysis proved -- a short genome doesn't necessarily translate to a dearth of genetic material. Researchers found that despite its shrunken genome, floating bladderwort boasts more genes than a number of more common plants, including the grape, coffee or papaya plants.
The research suggests that humped bladderwort is more than just economical, it's the opposite of repetitive. It's idiosyncratic -- and especially fluctuant. And it is this variability that allowed the bladderwort to pack so much genetic code into such a small space.
"The story is that we can see that throughout its history, the bladderwort has habitually gained and shed oodles of DNA," study leader Victor Albert, a biologist at Buffalo, explained in a press 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."
But constantly deleting genes to make up for its genetic replications and adaptations, the floating bladderwort seems have become exceptionally good a ridding itself of junk DNA, sequences that have little to no genetic or biological value.
"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," Albert said. "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," Albert added.
While floating bladderwort contains only a small percentage of junk DNA, almost 90 percent of the human genome is made up of throwaway genes.
The new study was published this week in the journal Molecular Biology and Evolution.