DNA barcode for world's plants agreed

28 July 2009

A DNA barcode to identify the world's plants has been agreed by an international team of researchers, including those at the Natural History Museum, scientists report today.

The announcement, published in PNAS (Proceedings of the National Academy of Sciences), is the culmination of 4 years of work by 52 scientists from 10 different countries and means there is now a global standard way for identifying plant species.

The barcode comprises 2 small regions found in the DNA of almost every plant on Earth. The barcodes will be put into a database that will be shared worldwide, providing the foundation for the widespread use of DNA technologies to identify plants.

A tricky task

Efforts to build DNA barcode databases for animal species have been underway since 2003. However, reaching consensus on which region or regions to use for plants proved more challenging.

Scientists needed to identify a section of DNA that was most suitable for telling most of the hundreds of thousands of plant species apart.

The CBoL (Consortium for the Barcode of Life) Plant Working Group compared the performance of 7 different DNA regions. 

As a result, portions of the genes rbcL and matK were selected to be the unique identifiers for plant species.

Using the technique

DNA barcoding will enable the identification of species from just tiny amounts of plant tissue and even from digested or processed samples in some cases.

The method can be used to identify endangered species in illegal trade, invasive and poisonous species, and material in forensic investigations. 

An important application will be the assessment of species diversity for biodiversity conservation, which suffers from a shortage of scientists with the specialist skills needed to identify plant specimens.

More work to do

Scientists estimate that there are around 400,000 species of land plants. The team can now begin the huge task of building the database of plant barcodes.

Dr Karen James, a Museum geneticist who took part in the research said, 'The process of reaching this collaborative decision has not been without its challenges – both biological and social. 

'But now that matK and rbcL have been selected, we are all looking forward to getting on with the important work of amassing a database of plant DNA barcodes against which queries can be compared.'

Trees first

One of the first global barcoding projects is to build a database of barcodes for the 100,000 species of tree worldwide.

Dr James concludes, 'The animal barcoding community has had a 4-year head start and we will be doing our best to catch up, starting with our first major campaign: to build a database of DNA barcodes for the world’s trees.

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