ONE of science鈥檚 great outstanding projects is about to begin 鈥� mapping what Charles Darwin called the 鈥済reat Tree of Life鈥�. When complete, the tree will finally reveal how all living creatures are related to one another.
The first projects, funded by the US National Science Foundation, were announced last week and will unravel the secrets of plants, spiders, birds and dinosaurs among others. But the whole programme is expected to take more than a decade.
鈥淭he fundamental question of biology is the connection among species on the Earth,鈥� says Shannon Hackett of the Field Museum of Natural History in Chicago. Making those connections will help researchers conserve species, restore ecosystems and control invading species. Medical researchers can use evolutionary data to trace the origin and spread of diseases, and to develop new medicines.
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Assembling the complete tree is no mean feat. Generations of biologists have sketched broad evolutionary patterns between groups of plants and animals and we have described around 1.7 million living species. But most are little studied, and millions of other living species have yet to be catalogued.
The Tree of Life project will take advantage of the latest techniques in molecular genetics and computer technology in a bid to resolve long-standing debates over the interpretations of morphologic data. Genetic tests can distinguish between species that look nearly identical, and DNA comparisons can tell you how long since the species diverged. The extent of genetic divergence can reveal long-lost relationships between highly evolved species, such as the links between whales and their nearest land-dwelling relations.
The first grants will pay for the mapping of seven key parts of the Tree of Life. At the base of the tree, the Institute for Genomic Research in Rockville, Maryland, will fully sequence several diverse types of little-studied bacteria in a bid to find out how they are related and trace the development of photosynthesis.
A team led by Charlie O鈥橩elly of the Bigelow Laboratory for Ocean Sciences in Maine will analyse DNA from 50 types of green algae and plants, and then use traditional morphology to identify fundamental divisions among non-flowering plants. Other groups will collect and analyse genetic and morphological data on over 1000 species of nematodes and 500 genera of spiders.
Hackett鈥檚 group will collect DNA sequence data from some 500 bird species, hoping to learn how modern birds diversified, and how their behaviours and other traits evolved.
A separate project will build a database including digital photographs and lists of features of every significant specimen of the predatory dinosaurs called theropods, thought to have given rise to birds. This will allow researchers to compare specimens at a more detailed level than before 鈥� previous studies only looked at the differences between theropod genera, says dinosaur project head Mark Norell of the American Museum of Natural History.
The scientists involved will have to come up with new ways of storing and searching data in order to handle the vast expanse of information. But Norell hopes to make the Tree of Life database so intuitive that researchers can compare specimens at their desks, instead of flying to museums around the world.