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Is something wrong with the tree of life?
Author(s) -
Martin William F.
Publication year - 1996
Publication title -
bioessays
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.175
H-Index - 184
eISSN - 1521-1878
pISSN - 0265-9247
DOI - 10.1002/bies.950180702
Subject(s) - tree of life (biology) , ancestor , molecular clock , common descent , biology , most recent common ancestor , evolutionary biology , abiogenesis , molecular evolution , biological evolution , fossil record , genealogy , paleontology , phylogenetics , phylogenetic tree , geography , history , gene , astrobiology , genetics , archaeology
A recent study (1) of sequence data from many different proteins has suggested that contemporary prokaryotes and eukaryotes may have shared a common ancestor as recently as 2 billion years ago (the molecular clock). Strong evidence from the geological record, however, indicates that oxygen‐producing microorganisms, perhaps similar to modern cyanobacteria, existed 3.5 billion years ago. The fossil evidence, therefore, suggests that any common ancestor of prokaryotes and eukaryotes must have existed at least 1.5 billion years earlier than suggested by the molecular clock evidence. The discrepancy between molecular and geological evidence for the age of modern cells is considered here, as are aspects of gene descent in the tree of life that might help to account for it.