UA Researcher Hones in on in Gaps in the Evolutionary "Tree of Life"

[Source: Deb Daun, BIO5] - Significant work remains before we can complete the evolutionary "tree of life," according to University of Arizona (UA) Professor of Ecology & Evolutionary Biology Michael Sanderson, PhD.

Sanderson, who is a BIO5 member, recently took a comprehensive look at all the organisms whose genomes we've sequenced—about 10 percent of life on earth—and detailed where gaps remain in our knowledge of the evolutionary connections among all organisms. His research was published in Science this summer.

"We know the most about organisms that are of direct relevance to humanity—mammals and primates, other vertebrates, and crop plants," Sanderson explains. "But when you begin looking at insects or fungi, for example, we have far less information." We also know more about the links among related groups of organisms—between mammals and birds, for example—than about the links among individual species.

Filling in the gaps is an ongoing international effort that involves not only gathering genetic data for the remaining 90 percent of life on earth, but also developing the computational tools to analyze that data—a task in which Sanderson's lab participates. "Even building a tree with only 20 to 30 species in it is very hard," Sanderson explains. "When you scale that up, it's among the hardest problems known in computational science. It's only in the past few years that we've even developed the technology to approach it."

Sanderson's lab is also searching for better ways of visualizing and presenting evolutionary data. "We'd like to develop tools for zooming around the tree of life in an interactive way," he says, adding that a tree may not even be the best metaphor for conveying this information. Possible alternative models include maps that, instead of branches, display information in terms of smaller boxes within larger ones.

Sanderson's work is funded by a $1 million grant from the National Science Foundation's (NSF)"Assembling the Tree of Life" project. Completing the plant portion of the tree of life is also one of the Grand Challenge questions being tackled by the iPlant Collaborative; Sanderson was one of the co-leads for the Grand Challenge proposal. The iPlant Collaborative is a $50 million NSF project located at the UA.

Sanderson says all this work highlights just how rich the diversity of life on our planet really is. "If we can show to people the complexity and the diversity to this evolutionary tree, I think that will help convey some of the excitement about how much is out there in the biological world," he says.