First draft of the ‘tree of life’.
A first draft of the ‘tree of life’ of the approximately 2.3 million species of animals, plants, fungi and microbes known, just been published.
A collaborative effort by eleven institutions, the tree represents relationships between living things that are evolutionarily separated from each other in time, arriving at the beginning of life on Earth 3,500 million years ago
Tens of thousands of smaller trees have been published in recent years for certain branches of the tree of life. – some containing over 100,000 species – but this is the first time these results have been combined into a single spanning tree life. The end result is open to free inquiry online digital resource.
“This is the first real attempt to connect the dots and put it all together,” said lead researcher Karen Cranston, University of Duke. “Think of it as version 1.0.” The evolutionary trees with branching diagrams often look like a cross between a candlestick and a map of metro, serve not only to determine whether aardvarks are more closely related sunfish or manatees. Understanding how the millions of species on Earth are interrelated helps scientists to discover new drugs, increase crop and livestock yields, and traces the origins and spread of infectious diseases such as HIV, Ebola and influenza .
Instead of building the tree of life from scratch, the researchers reconstructed together by compiling thousands of smaller fragments that had been posted online and merge together in a gigantic ‘ supertree ‘covering all listed species.
The initial project is based on about 500 trees under previously published studies. To assign the trees from different sources to the branches and twigs of one supertree, one of the biggest challenges was simply to account for name changes, alternate names, common misspellings and abbreviations for each species. The red bat East, for example, often appears in two scientific names, eastern red bat and boreal nycteridae.
“Although this is a major undertaking in its own right, this project tree life represents only a first step, “they wrote the researchers. For one thing, only a small fraction of published trees are digitally available. A survey of more than 7,500 phylogenetic studies published between 2000 and 2012 in more than 100 journals found that only one in six studies had deposited their data in a digital, downloadable format that researchers could use.
The vast majority of evolutionary trees are published in PDF and other image files that are impossible to include in a database or merge with other trees. “There is a big difference between the sum of what scientists know about how living things are related, and what is actually available digitally,” Cranston said. As a result, the relationships shown in parts of the tree, as the branches representing the families of peas and sunflower, are not always in agreement with expert opinion.
Other parts of the tree particularly insects and microbes, are difficult to reach. That’s because even the most popular online file genetic sequence – from which many evolutionary trees constructed – contains DNA data for less than five percent of the tens of millions of species believed to exist on Earth. “As important as showing what we know about relationships, this first tree of life is also important in the revelation of what we do not know,” said co-author Douglas Soltis of the University of Florida.
To help fill the gaps, the team is also developing software that will allow researchers to log and update and revise the tree as new data are collected on the millions of species that remain to be called or discover. “Twenty five years ago, people said that this objective of huge trees was impossible,” Soltis said. “The Tree of Life Open is an important point of departure that other researchers can now refine and improve in the coming decades”.
Original article here
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