Lamarck Rises From Dead

I saw this on Slashdot yesterday, but Wired has a nicer article. Basically, watercress has been found to have an error-correcting genetic code - some plants managed to undo the “hothead” mutation, reverting to the normal genes of their cressy grandparents.

The scientists suspect an RNA mechanism; I would have guessed it had something to do with polyploidy. The most common form of watercress is diploid, but there is a tetraploid variety.

[Update] The Chicago Sun-Times mentions the species, Arabidopsis thaliana, a.k.a. “mouse-ear cress.” Although A. thaliana is diploid now, it may have been polyploid 200 million years ago.

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