How much of protein sequence space has been explored by life on Earth?

David T. F. Dryden, Andrew R. Thomson, John H. White

Research output: Contribution to journalArticlepeer-review


We suggest that the vastness of protein sequence space is actually completely explorable during the populating of the Earth by life by considering upper and lower limits for the number of organisms, genome size, mutation rate and the number of functionally distinct classes of amino acids. We conclude that rather than life having explored only an infinitesimally small part of sequence space in the last 4 Gyr, it is instead quite plausible for all of functional protein sequence space to have been explored and that furthermore, at the molecular level, there is no role for contingency.

Original languageEnglish
Pages (from-to)953-956
Number of pages4
JournalJournal of the Royal Society, Interface
Issue number25
Publication statusPublished - 6 Aug 2008

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