A small, innocuous fern, growing only in New Caledonia, won the record for the largest genome of any living organism on earth on Friday, awarded by the Guinness Book. It has 50 times more DNA material than human cells.
Once unfurled, the helical structure of Tmesipteris oblanceolata, a plant that only reaches five to ten centimeters in height, would extend 106 meters.
The genome contains a set of pairs of nucleotides, bases, bringing together the genetic material of an organism. That of the fern has 160 Gbp (billion bases), bringing down by 7% more the previous record held by the Japanese plant Paris japonica. The human genome is far behind at 3.1 Gbp.
“We thought we had already reached a biological limit” with Paris japonica, Ilia Leitch, researcher at the British Royal Botanic Gardens Kew and co-author of the new study, told AFP. “We are at the extremes of biology,” according to him, with this little plant.
A disadvantage
A team went to study it in the French archipelago in the South Pacific in 2023 with local scientists, before publishing the results in the journal iScience.
This proves, in the case of this plant, which “looks like nothing”, that “the record holders are not always the most demonstrative seen from the outside”, commented a manager of the organization Guinness World Records, Adam Willward, quoted in a press release.
Humans have more than 30,000 billion cells. In each of them there is “a nucleus containing DNA, which is like the instruction manual explaining to an organism how to live and survive”, explains Ilia Leitch. To date, scientists have calculated the genome size of only around 20,000 organisms.
Everything indicates that a genome that is too large is disadvantageous, according to Leitch, because the larger it is, the more large cells it requires to contain it. In the case of the fern, this means larger leaf pores, which slow the growth of the plant. Copying all that DNA is also more complicated.
This article was automatically published. Sources: ats / afp
