From Tree To Web Poem by Margaret Alice

A Quixotic Quest

“The tree of life is a record of how every species that
ever lived is related to all others back to the origin of life.”

For a period of 150 years
biology sought the holy grail
of the tree of life – today
the tree has become obsolete
through negative evidence

Discovery of DNA structure led to
molecular evolution studying inheritance
as contained in the history of DNA sequences
finding species swapped genetic material
with each other, hybridising - thus the tree-
theory degenerates into impenetrable
thickets of interrelatedness

Bacteria and archaea swap
genetic material with other species
across huge taxonomic distances
in horizontal gene transfer (HGT)

Darwin assumed 'vertical' descent
but when genes were sequenced -
DNA replication and protein synthesis
showed the promiscuous exchange
of genetic information across
diverse groups

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Why Darwin was wrong about the tree of life
21 January 2009 by Graham Lawton
Magazine issue 2692. Subscribe and get 4 free issues.
For similar stories, visit the Evolution Topic Guide

Graham Lawton is features editor of New Scientist

http: //www.newscientist.com/article/mg20126921.600-why-darwin-was-wrong-about-the-tree-of-life.html? full=true