Re: Final conclusion on mit rec

Jim:

>For example, when Dr. Marcotrigiano states that mitotic recombination 
>is not uncommon, he means that it occurs in plants in general.

I don't think that anyone is saying that mitotic recombination doesn't 
occure in plants.  However, there does appear to be some question 
about how common or uncommon it may be.  Almost all the experiments 
that tend to demonstrate mitotic recombination use high doses of 
irriadation - conditions that are not normal.  I have never seen any 
estimates of just what the rate of mitotic recombination may be in 
higher plants.  In yeast and fungus it is quite low under experimental 
conditions designed to increase the rate of mitotic recombination.  
Take away the irradiation and the natural rate of mitotic 
recombination is even lower by several orders of magnitude.  

>"And he agreed on mit rec as an explanation for  a green edge 
>appearing on a yellow plant". That is not the way I read what he 
>said. I read that he said he "tended" to agree (with you)that it is 
>"possible".

It is always possible that mitotic recombination does occure in yellow 
hostas to produce a green edge, but chromosome damage or loss and 
point mutations could also cause a green edge and also transposible 
elements.  Unfortunately, Ben has not provided any proof for his claim 
that mitotic recombination is THE cause.  Actually, I think there is 
good evidence that mitotic recombination is not the cause.  Charlie 
Purtymun has a number of different green edged sports of Abiqua 
Recluse and they are all different, Paradigm being the best one.  If 
mitotic recombination were the cause of green edges showing up on 
yellow hostas then there should only be one type of green edged sport 
you could get from Abiqua Recluse.  You would also not get an all 
green sport of Fascination revert back to yellow steaking because, 
according to Ben such a plant should be homoszygous yy.  

Joe Halinar


---------------------------------------------------------------------
To sign-off this list, send email to majordomo@mallorn.com with the
message text UNSUBSCRIBE HOSTA-OPEN
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index