Re: iris DIGEST V1 #666

In this case "Treatment of plants with the demethylating agent, 5-azacytidine (5-azaC)"
This was an experiment designed to try to identify how vernalization had its effect. This was in 1998 before the identification of the MADS-box set of genes and their complicated interrelationship in vernalization. There are two genes involved in inhibiting bloom,. Frigida (FRI) and Flowering Locus C (FLC). These genes are present in addition to the vernalization gene, which requires these two genes to do their jobs. Exposure to vernalization temperatures turns off the FRI and FLC gene, allowing flowering to proceed . A defect in FLC results in plant not needing vernalization. A defect in FRI will cause plants to bloom earlier in the season. This sure sounds like our summer rebloomers that bloom so much earlier then the others of their ilk. Fall bloomers could very well have a defect in FLC gene. (speculation).
With animals the environment having the greatest effect on expression of epigenome is the womb. With animals the epigenome effect is set based on set of mother. Penatal diet can have an effect as shown by the agouti mouse experiment. Feeding mother BPA resulted in more fat yellow babies. Pre natal anti methylating supliments resulted in less yellow obese babies. Once out of the womb, this environment is gone and genome is fixed.
With plants, it doesn't matter too much what the initial set is as plants continue to grow and differentiate tissues from apial growth point(s). thus the environment can and will reset the plant epigenome to the current environment. The initial set may make a difference as to initial survival of the seed (speculation) 

Chuck Chapman


Date: Thu, 4 Sep 2008 16:39:54 -0700 (PDT)
From: christian foster <flatnflashy@yahoo.com>Subject: Re: [iris] Re: Re: Epigenome-sidebar 

Chuck,

I've seen that term, demethylation, in the checklists... thanks for
clearing up the meaning. I had inferred that it was probably not a "natural" 
process, so I'm glad to have conformation.

Thanks
Christian

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