Scientist: Work remains on evolutionary tree of life

[Source: ALAN FISCHER, Tucson Citizen] - Much work remains before scientists are equipped to develop a tree of life that shows how species are evolutionarily related, a University of Arizona researcher said.

Scientists have sampled genomic sequences from about 10 percent of the known 1.8 million species - which do not include bacteria, said Michael J. Sanderson, UA professor of ecology and evolutionary biology.

Sanderson's study, published in Science magazine July 4, assessed the DNA sequences for about 185,000 species to see what is available, and still needed, to work on the evolutionary tree of life, he said.

Building the tree of life to study the evolutionary relationship among various species is an international "grand challenge" facing scientists, Sanderson said.

"We looked at what does that 10 percent give us? Jow far can we get with that 10 percent," he said.

"It's really astonishing that we have 10 percent of known biodiversity in a DNA sequence database," he said. "But for much of the tree of life we have a long way to go," he said.

The available data focus on some groups of organisms - mammals, birds, other vertebrates and things related to agriculture - that have direct or immediate impact on humans, he said.

"But that takes care of a few thousand species. The others we know far less about," he said. "We have to gather a lot more of these DNA sequences for these species before we can think about building a tree of life."

Improved technology in computers and genetic sequencing should help the effort, said Sanderson, a member of the UA BIO5 Institute.

"We could not have done this kind of computing even five years ago." he said.
But now scientists must go out and get DNA for the 90 percent of species not yet sampled. he said.

It will likely be many decades before the genetic data are available to build a full evolutionary tree of life, he said.

Sanderson said his five-year research effort was funded by a $1 million National Science Foundation grant.