Tiny fern breaks world record for largest genome on Earth — with DNA stretching taller than the Statue of Liberty

A small, seemingly normal fern that only grows on a remote Pacific island was on Friday crowned holder of the Guinness World Record for having the largest genome of any organism on Earth.

The New Caledonian fern, Tmesipteris oblanceolata, has more than 50 times more DNA packed into the nucleus of its cells than humans.

If the DNA of one of the fern’s cells – which is just a fraction of a millimeter wide – were unraveled, it would stretch 100 meters, scientists said in a new study.

Standing upright, the DNA would be taller than the Statue of Liberty and the tower that houses London’s famous Big Ben bell.

The fern’s genome weighed in at an impressive 160 gigabase pairs (Gbp), the measurement of DNA length.

This is 7% higher than the previous record holder, the Japanese plant Japanese Paris.

The human genome is a relatively insignificant 3.1 Gbp. If our DNA were unraveled, it would be about six feet long.

Study co-author Ilia Leitch, a researcher at the Royal Botanic Gardens Kew in the United Kingdom, told AFP that the team was “really surprised to find something even bigger than Paris japonica.”

“We thought we had already reached the biological limit. We are truly reaching the extremes of biology,” she said.

The fern, which grows two to four inches tall, is only found in New Caledonia, a French Pacific territory that has recently experienced unrest.

Two members of the research team traveled to the main island, Grand Terre, in 2023 and worked with local scientists on the study, which was published in iScience magazine.

“Innocuous-looking fern”

Guinness World Records has awarded the fern the coveted “largest genome title.”

“To think that this innocuous-looking fern has 50 times more DNA than humans is a humbling reminder that there is still so much about the plant kingdom that we don’t know and that the record holders are not always the flashiest on the outside,” he said. Guinness. World Records editor-in-chief Adam Millward said: according to the BBC.

It is estimated that humans have more than 30 trillion cells in our bodies.

Inside each of these cells is a nucleus that contains DNA, which is like an “instruction book that tells an organism like us how to live and survive,” Leitch explained.

All of an organism’s DNA is called its genome.

So far, scientists have estimated the genome size of about 20,000 organisms, just a fraction of life on Earth.

In the animal kingdom, some of the largest genomes include certain lungfish and salamanders with around 120 billion base pairs, according to the BBC.

Although plants have the largest genomes, they can also have incredibly small genomes. The genome of the carnivorous Genlisea aurea is just 0.06 Gbp.

But we humans don’t need to feel inadequate when comparing ourselves to the mighty T. oblanceolata.

All the evidence suggests that having a huge genome is a disadvantage, Leitch said.

The more DNA you have, the bigger the cells will need to be to compress everything.

For plants, larger cells mean that things like the pores in the leaves have to be larger, which can make them grow more slowly.

It is also more complicated to make new copies of all this DNA, limiting your reproductive capabilities.

This means that the most massive genomes are seen in slow-growing perennial plants, which cannot easily adapt to adversity or face competition.

Genome size can therefore affect how plants respond to climate change, land use change and other environmental challenges caused by humans, Leitch said.

“How does he survive with so much DNA?”

There may still be larger genomes out there somewhere, but Leitch thinks this fern must be close to the limit.

“How does it work? How do you survive with so much DNA?” Leitch told the BBC.

Scientists don’t know what most of the DNA does in such large genomes, she admitted.

Some say most of it is “junk DNA.”

“But that’s probably our own ignorance. Maybe it has a function, and we haven’t discovered it yet,” Leitch said.

Jonathan Wendel, a botanist at Iowa State University not involved in the research, agreed that it was “surprising” how much DNA the fern contains.

But this only “represents the first step”, he told AFP.

“A big mystery is the meaning of all this variation – how do genomes grow and shrink, and what are the causes and evolutionary consequences of these phenomena?”