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  Topic: The rise and fall of adaptive mutation, POTD< Next Oldest | Next Newest >  

Posts: 319
Joined: May 2002

(Permalink) Posted: Jan. 25 2003,18:00   

Charlie D gives a great brief intro on why adaptive mutation ain't:

ARN thread:
Topic: Directed mutation;f=13;t=000588

Originally posted by charlie d:
I have no idea when that paper was written, but it lists no references later than 1995.  Thus, its enthusiasm for the "targeted mutation" phenomenon, its belief that it represents a fundamental challenge to the prevailing genetic paradigm, and its conclusion that "there is no explanation for it", is not surprising, considering that the hypothesis itself began to crumble in earnest in 1996 with the publication of this article by Prival and Cebula:
Prival MJ, Cebula TA Adaptive mutation and slow-growing revertants of an Escherichia coli lacZ amber mutant. Genetics 1996 Dec;144(4):1337-41,
and eroded further after this article by Patricia Foster (who was one of the original discoverers of the adaptive mutations phenomenon):
Foster PL. Nonadaptive mutations occur on the F' episome during adaptive mutation conditions in Escherichia coli. J Bacteriol. 1997 Mar;179(5):1550-4.

These and other findings prompted Foster herself to write the now classic review (available for free here): Foster PL. Adaptive mutation: has the unicorn landed? Genetics. 1998 Apr;148(4):1453-9,
a virtual obituary for the "lamarckian" interpretation of the phenomenon.

A more detailed review is this one (but subscription is required to access the actual paper): Foster PL. Mechanisms of stationary phase mutation: a decade of adaptive mutation. Annu Rev Genet. 1999;33:57-88.

At the current state of affairs, it is very clear that mutations during "adaptive mutagenesis" are not specifically directed towards the gene(s) under selection, i.e. they are entirely darwinian (random wrt to fitness), and are often the result of generalized hypermutation mechanisms (the last important piece of the puzzle being the publication of this paper last year):  Hendrickson H, Slechta ES, Bergthorsson U, Andersson DI, Roth JR. Amplification-mutagenesis: evidence that "directed" adaptive mutation and general hypermutability result from growth with a selected gene amplification. Proc Natl Acad Sci U S A. 2002 Feb 19;99(4):2164-9.

For those interested in the most recent and actual history of the "targeted mutation" saga, I recommend this recent excellent review of the issue, available for free here: Rosenberg SM Evolving responsively: adaptive mutation. Nat Rev Genet 2001 Jul;2(7):504-15


Edited by niiicholas on Jan. 25 2003,18:01

charlie d

Posts: 56
Joined: Oct. 2002

(Permalink) Posted: Jan. 25 2003,19:08   

Hi Nic:
thanks for cross-posting this.  

I just want to make very clear that the topic of adaptive mutagenesis is in fact very much alive and well, and still very interesting from both a molecular and an evolutionary point of view.  What seems to have lost all steam is the original "neo-lamarckian" interpretation of the phenomenon, that Cairns, Foster, Shapiro, Hall and others initially supported (and arguably with some reason, given the data).

Most importantly, I think the story is very instructive regardless of its ending (the current one, that is. ;) ) .  Here is a set of results that shakes the very foundation of darwinian evolutionary theory, coming (gasp!) from that old bastion of the Modern Synthesis - bacteriology (even essentially rewriting Luria and Delbrueck's experiment! ).  And what does the Darwinian establishment, this entrenched Cabal of scheming censors, do?  They publish the relevant papers in Nature, PNAS, Genetics and the like, with great evidence (and, admittedly, plenty of grumbling in the letters section).  If Behe & C had as much as one tenth of the data that Cairns had in 1988, they'd get them published too.

Edited by charlie d on Jan. 25 2003,19:09

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