Thursday, October 05, 2006
From Scientific American Blog Sciam Observations: One of the most exciting results in biology last year (1) was a possible violation of the most basic rules of genetic inheritance, reported to occur in the lab plant Arabidopsis. If true, it would be an enormous discovery. But in a brief communication published in last week's Nature (2), a second group (Peng et al. of the University of California, Los Angeles) reports they were unable to replicate the result, which is generally not a good sign.
To recap the earlier report, researchers said that the offspring of plants possessing two mutated copies of a gene called hothead unexpectedly received one or two regular versions of the gene instead, apparently violating Mendel's rule that an organism's genes are a grab-bag from its parents. The plants showed the same oddity in other genes across the genome...
...In the Nature communication, Peng et al. of UCLA report that when they grew hothead mutants in isolation, the offspring did not revert back, even in thousands of plants... Tellingly, they say they did find reversions when they grew hothead mutants around other plants, suggesting that the mutants are highly susceptible to cross-pollination, rather than being exclusively self-fertilized as is normal for Arabidopsis...
...In a published reply (3), Lolle, Pruitt and their original co-authors agree that Peng et al.'s findings do indeed smack of cross-pollination, but they contend that some of their results, such as double reversions of both mutant genes to the regular form, are inconsistent with cross-pollination being the whole story in their case.
(1) "RNA to the Rescue: Novel inheritance patterns violate Mendel's laws" (Sciam)
(2) "Plant genetics: Increased outcrossing in hothead mutants" (Abstract)
(3) "Increased outcrossing in hothead mutants (Reply)" (Abstract)
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