The survival of only important genes suggests that the carnivorous bladderwort’s DNA pruning was driven by natural selection

In most organisms, the number of genes in their genome is in line with their size and complexity. It’s pretty rare that small organisms have less genome but far more genes than bigger organisms. Carnivorous bladderwort is one such organism. This plant appears simple at first glance, but packs some mind-bending genetic material.

Carnivorous bladderwort

 Carnivorous bladderwort’s DNA has 28,500 genes

A team of scientists led by Victor Albert of the University of Buffalo has revealed the genetic structure of the bladderwort, also known as Utricularia gibba. The aquatic plant uses vacuum created by its 1mm long bladders to suck in animal prey. Findings of the study were published in the latest issue of the journal Molecular Biology and Evolution.

The carnivorous bladderwort’s DNA has 80 million base pairs, which is six times smaller than that of grape and 38 times fewer than the human genome. Despite its smaller DNA, the little bladderwort has 28,500 genes, compared to about 25,000 genes in humans and 26,300 genes in grapes. How is it that its genetic material is bigger on the inside?

The study is based on the previous work done by lead author Victor Albert. In 2013, Albert and his colleagues found that the carnivorous bladderwort significantly lacked the non-coding or “junk” DNA. Most organisms, including humans, have junk DNA in abundance. Scientists say that about 90% of human DNA is non-coding or junk.

Bladderwort has only 3% non-coding DNA

 

In the carnivorous bladderwort, only 3% of DNA is non-coding. That’s because of its deep history of intense DNA editing. It is constantly gaining and removing DNA at a rapid pace. Researchers said that the evolutionary rate of loss of non-coding DNA in bladderwort was much higher than in other plants. Victor Albert said the bladderwort genome was “subjected to some heavy duty deletion mechanisms.” Only the really important genes survived the deletion mechanism.

The fact that only important genes prevailed suggests that the carnivorous bladderwort’s DNA pruning was driven by natural selection, said Albert.