London, United Kingdom
February 4, 2008
Source:
Imperial College London
A 'barcode' gene that can be used
to distinguish between the majority of plant species on Earth
has been identified by scientists who publish their findings in
the Proceedings of the National
Academy of Sciences journal today.
This gene, which can be used to identify plants using a small
sample, could lead to new ways of easily cataloguing different
types of plants in species-rich areas like rainforests. It could
also lead to accurate methods for identifying plant ingredients
in powdered substances, such as in traditional Chinese
medicines, and could help to monitor and prevent the illegal
transportation of endangered plant species.
The team behind the discovery found that DNA sequences of the
gene 'matK' differ among plant species, but are nearly identical
in plants of the same species. This means that the matK gene can
provide scientists with an easy way of distinguishing between
different plants, even closely related species that may look the
same to the human eye.
The researchers made this discovery by analysing the DNA from
different plant species. They found that when one plant species
was closely related to another, differences were usually
detected in the matK DNA.
The researchers, led by Dr Vincent Savolainen, dual appointee at
Imperial College London's Department of Life Sciences and the
Royal Botanic Gardens, Kew, carried out two large-scale field
studies: one on the exceptionally diverse species of orchids
found in the tropical forests of Costa Rica, and the other on
the trees and shrubs of the Kruger National Park in South
Africa. Dr Savolainen and his colleagues in the UK worked
alongside collaborators from the Universities of Johannesburg
and Costa Rica who played a key role in this new discovery.
Using specimens collected from Costa Rica, Dr Savolainen and
colleagues were able to use the matK gene to identify 1,600
species of orchid. In the course of this work, they discovered
that what was previously assumed to be one species of orchid was
actually two distinct species that live on different slopes of
the mountains and have differently shaped flowers adapted for
different pollinating insects.
In South Africa the team was able to use the matK gene to
identify the trees and shrubs of the Kruger National Park, also
well known for its big game animals.
Dr Savolainen explains that in the long run the aim is to build
on the genetic information his team gathered from Costa Rica and
South Africa to create a genetic database of the matK DNA of as
many plant species as possible, so that samples can be compared
to this database and different species accurately identified.
"In the future we'd like to see this idea of reading plants'
genetic barcodes translated into a portable device that can be
taken into any environment, which can quickly and easily analyse
any plant sample's matK DNA and compare it to a vast database of
information, allowing almost instantaneous identification, " he
says.
Although Dr Savolainen concedes that such technological
applications may be some years away from realisation, he says
the potential uses of the matK gene are substantial: "There are
so many circumstances in which traditional taxonomic
identification of plant species is not practical - whether it be
at ports and airports to check if species are being transported
illegally, or places like Costa Rica where the sheer richness of
one group of plants, like orchids, makes accurate cataloguing
difficult."
The matK gene may not, however, be able to be used to identify
every plant species on Earth. In a few groups of species,
additional genetic information may be required for species-level
identification because hybridization - where species cross-breed
and genetic material is rearranged - may confuse the information
provided by matK.
This research was funded by the Defra Darwin Initiative, the
Universities of Johannesburg and Costa Rica, the South African
National Research Foundation, the Royal Botanic Gardens, Kew,
and the Royal Society.
Joan Ruddock, Minister for Climate Change and Biodiversity said:
"This is a great breakthrough that could save many endangered
plants. The Defra-funded Darwin Initiative has a reputation for
producing real and lasting results and I congratulate everyone
involved in this project which could have huge benefits for
plant identification and conservation in the future." |
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