Moss genome shows how plants invaded the land and learned to survive heat a...( Berkeley -- Some 400 million years a...)

Berkeley -- Some 400 million years ago, on a lifeless lakeshore lapped by waves, floating algae learned to survive in the open air and launched an invasion that transformed the Earth into a green paradise.

The secrets of these first steps onto land are now being revealed thanks to the sequencing of a modern descendent of these first land dwellers, a dainty moss called Physcomitrella patens that sprouts on recently exposed shorelines, quickly fruits, and then dies.

The sequencing of the moss genome was reported today (Thursday, Dec. 13) in Science magazine's rapid online publication Science Express by an international team of scientists led by the Department of Energy's Joint Genome Institute in Walnut Creek, Calif. It will be printed in Science in January 2008.

"Land plants may have evolved in this transition zone where, as the water rises and falls, aquatic plants found themselves repeatedly but not continuously exposed to the air and had to come up with ways of protecting their seeds or spores from desiccation," said Joint Genome Institute project leader Jeffrey Boore, an adjunct associate professor of integrative biology at the University of California, Berkeley, and chief executive officer of Genome Project Solutions in Hercules, Calif.

Because of the key position of mosses in the evolution of green plants, the Physcomitrella genome may hold the key to the origin of such traits as desiccation tolerance, said Brent Mishler, a UC Berkeley professor of integrative biology who, with Ralph Quatrano of Washington University in St. Louis, Mo., originally proposed the moss genome project.

"One of the claims to fame of mosses is the ability to dry up completely and come back to life again," said Mishler, who is director of the University and Jepson Herbaria, two collections of pressed plants housed together along with research labs, libraries and archives at UC Berkeley.

"We have been looking for years at all lev
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