Both chloroplasts and mitochondria originated more than a billion years ago, when bacteria colonized early single-celled organisms, establishing a symbiotic relationship that has allowed plant cells to get energy from sunlight and both plant and animal cells to produce energy efficiently.
Among the questions Mishler, Boore and their colleagues want to answer are, how many times has land been colonized from the sea by green algae, where did plants acquire the adaptations essential to life on land, and how many times did multicellular plants evolve?
To date, only two entire plant genomes have been sequenced - a plant called Arabadopsis thaliana from the mustard family and rice - and JGI is at work on a third, the poplar tree.
"Data from the already sequenced genomes have not yet been analyzed comparatively," said Mishler, who specializes in the study of mosses and other bryophytes. "Only about 15 green plant chloroplast genomes have been sequenced, and even fewer mitochondrial genomes - about 10 - so our project will be a big step forward."
The group plans to test various ways of comparing genomes to elicit evolutionary relationships. In particular, they want to find the best methods to use for groups of organisms that have a long evolutionary history.
"We're going to test theories and methods for analyzing genes comparatively," said Mishler, who was one of the leaders of the "Deep Green" initiative that several years ago reported the first draft of the tree of life for green plants. "Right now we don't know the best ways to analyze the DNA once we have it."
Typically, biologists look at the same gene in many different species and document the sequence changes th
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Contact: Robert Sanders
rls@pa.urel.berkeley.edu
510-643-6998
University of California - Berkeley
25-Nov-2002