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Astrobiology Science Conference 2015 (2015)
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EXPERIMENTAL
EVOLUTION
OF
MULTICELLULARITY
IN
THE
GREEN
ALGA
CHLAMYDOMONAS REINHARDTII. Matthew D. Herron1, William C. Ratcliff2, Jacob Boswell3, Michael Travisano4, and Frank Rosenzweig5, 1University of Montana, 32 Campus Dr., Missoula, MT 59812 [email protected]. 2Georgia Institute of Technology, 310 Ferst Dr., Atlanta, GA 30332,
[email protected]. 3University of Montana, 32 Campus Dr., Missoula, MT 59812, [email protected]. 4University of Minnesota, 100 Church St. S.E., Minneapolis MN 55455,
[email protected]. 5University of Montana, 32 Campus Dr., Missoula, MT 59812, [email protected].
The transition to multicellular life was one of a few
major events in the history of life that created new opportunities for more complex biological systems to
evolve. Indeed, multicellularity is a prerequisite for the
evolution of large, complex organisms such as plants
and animals. An understanding of the ecological conditions and evolutionary mechanisms that favor this key
innovation is necessary to determine where and with
what likelihood complex life may have arisen beyond
Earth. We have generated de novo origins of simple
(undifferentiated) multicellularity in two separate experiments in the green alga Chlamydomonas reinhardtii, a species that has not had multicellular ancestors.
Furthermore, the form of multicellularity observed differs substantially between experiments, suggesting that
the particulars of the transition to multicellular life depend not only on the nature of the unicellular ancestor,
but on the specific selective pressures driving the transition as well. To understand the genetic changes underlying the transition to multicellular life, we used a
combination of whole-genome sequencing, genomewide expression analysis, and bulked segregant analysis.