International Society for History, Philosophy, and Social Studies of Biology


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Program

WEDNESDAY, JULY 8  /  17:30 - 19:00  /  Salle Marie Gérin-Lajoie
Plenary session
HUGGING THE TREE OF LIFE

W. Ford Doolittle (Dalhousie University, Canada)

For 30 years, gene sequences were used to construct phylogenetic trees without serious concern that different genes might actually have different evolutionary histories because of transfer “across species lines” (Lateral Gene Transfer, or LGT). But now comparative genomic data show LGT to be so frequent on an evolutionary time scale that a maximum of 5%, and possibly 0%, of the genes in any bacterial genome are likely to have the same history back to any last common bacterial ancestor. LGT is also not an insignificant force in the evolution of microbial eukaryotes. The effort to construct a universal Tree of Life (TOL) may thus be rendered futile, and we need to rethink what we want the TOL to do for us – underwrite systematics, prove the Theory of Evolution or recreate a history of speciation events and cell divisions back to the beginning of Life. Conflict among evolutionary biologists shows they have conflated these goals. My purpose in this talk will be to disentangle them.