Scimex: In a UK study that would put Sesame Street's Count to shame, researchers
have attempted to measure the total sum of DNA on Earth. The authors
found the final number to be in the 50 trillion trillion trillions (5
followed by 37 zeros), and say that the study can now lead to new
research opportunities about life on Earth. The first study to count the sum total of all DNA everywhere on Earth
– in the cells of plants, animals and tiny organisms such as bacteria –
estimates that it weighs about 50 billion tonnes; enough to fill one
billion shipping containers. This is equivalent to 50 trillion trillion
trillion (5 followed by 37 zeros) of the fundamental chemical "letters" –
known as base pairs – that allow DNA to encode genetic information.
The authors say that their study, which publishes on June 11th in the Open Access journal PLOS Biology,
gives a new perspective on Earth's biodiversity, by enabling
comparisons between various groups of organisms. They suggest that it
could provide a fresh approach to conservation planning and
policymaking.
The researchers, based at the University of
Edinburgh, used available data on the genetics of various species and
their populations to make the first estimate of the amount of DNA
present in plants and animals. They also researched DNA data for other
forms of life including bacteria and fungi – which include some of the
most populous organisms on Earth.
To store the information
contained in the biosphere's DNA you would need a billion trillion of
the world's most powerful supercomputers (1 followed by 21 zeros). And
as all the cells on the planet use that information by transcribing
their genes from DNA to RNA, the authors estimate that they use a total
processing power greatly exceeding a trillion trillion operations per
second.
Aside from highlighting these spectacular computational
properties of life on Earth, the authors hope their approach might
enable the targeting of geographical regions or habitats that may be
more important than others for preserving biodiversity, which could be
useful as a complementary method to assist prioritizing and assessing
conservation efforts.
They say that their study has revealed
opportunities for new research about life on Earth, such as a better
understanding of the density of organisms in various environments, and
how genome sizes and chromosome levels differ across kingdoms. They
emphasise that this study represents an initial estimate, and expect
that their calculations can be refined as more information becomes
available.
Hanna Landenmark of the School of Physics and
Astronomy, University of Edinburgh – one of the authors of the article –
said: "This preliminary estimate could potentially provide an
additional way to quantify natural and anthropogenic processes and
changes in the biosphere, which can inform conservation efforts and
assessments of habitat and diversity loss."
Another author,
Professor Charles Cockell, added: "This offers a way to look at the
total information content of the biosphere and how it's changed over
time, rather than just focusing biodiversity assessments on the number
and types of species."