Kew scientists discover the largest genome of them all
Scientists at Kew’s Jodrell Laboratory have discovered that Paris japonica, a striking rare native plant of Japan, has the largest genome of them all – bigger than the human genome and even larger than the previous record holder - the
The diversity of genome sizes (the amount of DNA) in plants and animals has fascinated - but at the same time puzzled - scientists since this variation was first detected in the early 20th century. How and why such diversity evolved are important unanswered questions, as we know that this phenomenon has biological and ecological consequences affecting the distribution and persistence of biodiversity.
There is a staggering diversity of genome sizes. The smallest genome so far reported (0.0023 picogram (pg) of DNA) is found in a parasite (Encephalitozoon intestinalis) of humans and other mammals. The human genome, at 3.0 pg, is 1,300 times larger than this, but this pales into insignificance compared to those found in some animals and plants.
We were astounded when we discovered that this small stunning plant had such a large genome — it’s so large that when stretched out it would be taller than Big Ben.Ilia Leitch, Research Scientist in Kew's Jodrell Laboratory
Among animals, some amphibians have enormous genomes, but the largest recorded so far is that of the marbled lungfish (Protopterus aethiopicus) with 132.83 pg(3) . Among plants, the record holder for 34 years was a species of fritillary (Fritillaria assyriaca). However earlier this year a Dutch group knocked the fritillary off the top spot when they found that a natural hybrid of trillium (Trillium × hagae), related to herb paris, had a genome just 4% larger than the fritillary (132.50 pg).
Discovering the largest genome known to science
This was widely thought to be approaching the maximum size that a genome could reach, until this summer when a team of Kew scientists discovered that the genome of another close relative of herb paris, Paris japonica from Japan, is a staggering 15% bigger than the genome of either the trillium or the fish at a whopping 152.23 pg.
Ilia Leitch, Research Scientist in the Jodrell Laboratory at Kew says “We were astounded when we discovered that this small stunning plant had such a large genome — it’s so large that when stretched out it would be taller than Big Ben.
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Scientific Research & Data
Citation: Pellicer J, Fay MF, Leitch IJ. 2010. The largest eukaryote genome of them all? Botanical Journal of the Linnean Society Doi: http://dx.doi.org/10.1111/j.1095-8339.2010.01072.x
- Information about genome size in plants is summarized in the Plant DNA C-values database maintained by Kew.
- Similar information about animal genomes can be found in the Animal Genome Size database.
- The Linnean Society of London - the world’s oldest active biological society.
- The Botanical Journal of the Linnean Society.