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Your Christmas tree has seven times more DNA than you do – time to map it
10 December 2009
Take a close look at your Christmas tree – it has seven times more genetic material (DNA) than you do! Why this is so is still largely unknown, but now the DNA of the spruce is going to be mapped by Swedish researchers from Umeå Plant Science Center (a collaboration between the Swedish University of Agricultural Sciences (SLU) and Umeå University), the Royal Institute of Technology (KTH), and the Karolinska Institute (KI), with the aid of a SEK 75 million grant from the Knut and Alice Wallenberg Foundation.
Coniferous trees have dominated major parts of the earth for hundreds of millions of years. When primitive batrachians crawled around Carbon Age forests, they were surrounded by conifers. Conifers survived the geological disaster 250 million years ago that paved the way for the age of the dinosaurs. When the impact of a meteorite wiped out the dinosaurs, conifers lived on. Today conifers dominate major regions of the earth – the combined weight of all the people on earth is less than that of the conifers in Jämtland County in central Sweden.
Apparently conifers managed as early as 300 million years ago to create an extremely successful genetic make-up that has allowed them to dominate the globe, but what does it look like? All conifers have twelve chromosomes, but they are extremely large: a cell from a spruce or pine has seven times as much DNA as a human cell does. Why do conifers have so much DNA? Does it have to do with their having thrived for millions of years on earth, and do they really have more genes than you and I, or are their genes simply more ‘diluted’? This is not known, but their enormous amount of DNA has entailed that scientists have not dared to tackle a mapping of the complete genome of coniferous trees.
Now a Swedish research team, consisting of scientists from Umeå Plant Science Center (UPSC), a research center that is run jointly by Umeå University and SLU, and from KTH and KI, both in Stockholm, will finally be addressing this huge challenge with the aid of a grant of SEK 75 million from the Knut and Alice Wallenberg Foundation.
The spruce is Sweden’s ecologically and economically most important plant. Spruce dominates the forests of southern and central Sweden and is the most important raw material for the Swedish forestry industry.
“The genetics of the spruce are truly exciting,” says the project director, Professor Pär Ingvarsson at UPSC. “Genetically, trees differ tremendously from each other, and while Swedish forest genetics has always been prominent, this constitutes a giant step forward in the work to achieve tree nursery material that is adapted to the very different conditions that prevail in our country, above all in the time of climate change we are facing.”
“The fact that the Swedish spruce will be the first conifer to have its genome mapped is extremely important to both Swedish forestry research and the forestry industry,” says Professor Ove Nilsson at UPSC, who chairs the project’s steering group. “A complete mapping of the genes of the spruce will revolutionize Swedish tree research and enable us to make more efficient use of wood raw material.”
“For example, it will provide us with the possibility of developing genetic tests for the various properties of trees, such as the fuel value of the wood, or the trees’ frost resistance and resistance to diseases, just as the mapping of the human genome has made this possible in medicine,” says Stefan Jansson, a professor at UPSC.
These scientists are now able to take on this challenge largely because DNA sequencing technology has been developed so extremely rapidly.
“It would have been impossible to tackle this project just a couple of years ago,” says Professor Joakim Lundeberg, KTH. The government’s major allocation to the Science for Life Laboratory, which is slated to be northern Europe’s largest center for genome research, gives us access to this equipment, and the spruce project will be the Laboratory’s first flagship project.
“Many other Swedish scientists will benefit from this project, so the eventual aggregate impact will be huge,” says Jan Stenlid, a professor at SLU in Uppsala. “For instance, we will have an entirely new capacity to understand and thereby combat two major scourges for Swedish forestry, root rot and the pine weevil.”
The project is projected to take four to five years, and besides the eight Swedish researchers – Björn Andersson, KI, Rishikesh Bhalerao, UPSC, Rosario Garcia Gil, UPSC, Pär Ingvarsson, UPSC, Stefan Jansson, UPSC, Joakim Lundeberg, KTH, Ove Nilsson, UPSC, and Björn Sundberg, UPSC – Canadian, Italian, and Belgian researchers will contribute to the project, which, as far we know, is the largest project in the world to tackle the species that has the largest DNA.