Genetic Equidistance: A Puzzle in Biology?

Here I wish to discuss my thesis that the phenomenon of genetic equidistance presents a problem in biology: how do we know if this phenomenon is the result of the amount of time that has lapsed since any two or more organisms have diverged, or is it largely the result of the epigenetic complexity of organisms imposing restraints on the amount of mutations those organisms tolerate? Indeed, if the epigenetic complexity of an organism does impose a such restraint, then the genetic equidistance result would still be observed, regardless of the time that has lapsed since divergence.On a slight tangent, if this was the case, then functionally redundant protein sequences cannot always give us accurate conclusions with regards to phylogenetic relationships. Edited by Adminnemooseus, : Add a blank line - Because I had nothing easy better to do.

Google returns nothing for "epigenetic equidistance." You'll have to explain a bit more.

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--	Percy
	EvC Forum Director

Google "genetic equidistance" and you'll get the necessary information.To quote Wikipedia,
"The genetic equidistance phenomenon was first noted in 1963 by E. Margoliash, who wrote: "It appears that the number of residue differences between cytochrome C of any two species is mostly conditioned by the time elapsed since the lines of evolution leading to these two species originally diverged. If this is correct, the cytochrome c of all mammals should be equally different from the cytochrome c of all birds. Since fish diverges from the main stem of vertebrate evolution earlier than either birds or mammals, the cytochrome c of both mammals and birds should be equally different from the cytochrome c of fish. Similarly, all vertebrate cytochrome c should be equally different from the yeast protein." For example, the difference between the cytochrome C of a carp and a frog, turtle, chicken, rabbit, and horse is a very constant 13% to 14%. Similarly, the difference between the cytochrome C of a bacterium and yeast, wheat, moth, tuna, pigeon, and horse ranges from 64% to 69%. Together with the work of Emile Zuckerkandl and Linus Pauling, the genetic equidistance result directly led to the formal postulation of the molecular clock hypothesis in the early 1960s. Genetic equidistance has often been used to infer equal time of separation of different sister species from an outgroup."Edited by Adminnemooseus, : Add the quote box for the quoted material, etc.

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