Scientists at Kew's Jodrell Laboratory have discovered that Paris Japonica, a striking rare native of Japan(1), has the largest genome(2) of them all -- bigger than the human genome and even larger than the previous record holder -- the marbled lungfish.
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 because we know that it has biological and ecological consequences that affect the distribution and persistence of biodiversity.
There is a staggering diversity of genome sizes. The smallest genome (3) so far reported (0.0023 pg of DNA) is found in a parasite of humans and other mammals. The human genome, at 3.0 pg, is 1300 times larger than this, but this pales into insignificance compared to those found in some animals and plants.
Among animals, some amphibians have enormous genomes, but the largest recorded so far is that of the marbled lung fish with 132.83 pg(3) . Among plants, the record holder for 34 years was a species of fritillary until earlier this year when a Dutch group knocked the fritillary off the top spot when they found that a natural hybrid of trillium , related to herb paris had a genome just 4% larger than the fritillary (132.50 pg).
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
sources:
http://www.sciencedaily.com/releases/2010/10/101007120641.htm information
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