Largest fungal genome

The largest genome (i.e., total amount of DNA in the nucleus of a cell) for any fungus assessed to date using best-practice methods is 5.8 billion base pairs (Gbp, or gigabases), for Neottiella rutilans. The orange-yellow cup fungus, widespread across Europe and North America, is typically found parasitizing mosses in open areas with sandy soil. The findings were reported by mycologist Dr Bellis Kullman (of the Estonian University of Life Sciences) from the XVII Symposium of the Baltic Mycologists and Lichenologists in September 2008.

Compared to other sac fungi (Ascomycota), the largest phylum of fungi to which it belongs, the genome of N. rutilans is approximately 150 times larger than average. As well as the number of base pairs, genome size can also be expressed as a weight in picograms (one-trillionth of a gram): the total DNA of N. rutilans weighs in at 5.93 picograms.

This fungus possesses almost twice as much genetic material than that found in the nuclei of human cells (3.2 Gbp).

The largest genome for any organism assessed by comparable techniques is 160.45 Gbp for the Tmesipteris oblanceolata fork fern, native to tropical forests in New Caledonia and nearby Pacific islands as reported in iScience on 31 May 2024.