Re: Re: HYB: more pink

In a message dated 11/25/00 11:18:33 AM Mountain Standard Time, Fred Kerr 
writes:

<< Just a little more grist for the pink theorists: 1) when the tangerine 
factor 
 is present in two doses in diploids, the plants are not pink. Anybody know 
 what happens when it is present in three doses in triploids? 2) what about 
 pink and yellow blends like Black Hills Gold in which there are yellow areas 
 and pink areas on the same petal. Surely all the cells are four dose (or are 
 they?) genotypes and should be pink.
>>

I have grown two pinks from a diploid x tetraploid cross, which behave as 
triploids but were not counted.  IMO, this varying expression lends support 
to the theory that the tangerine factor is not a single, simple gene.   

The yellow areas and pink areas on the same petal strike me as a pattern 
effect, not strictly related to color.  Just as we have pink-ground plicatas 
and bi-colors.
 
<<
 The relationship between anthocyanins and carotinoid pigments is easily over 
 simplified. While brown and red may be the result of an interaction of the 
 two classes of pigments, they are not the only result.  Two sibling 
varieties 
 Kevin's Theme and Cosmic Wave differ only in presence of carotinoids in KT 
 and the lack in of carotinoids in CW. In CW the anthocyanin  expresses as 
 blue, but in KT it expresses as blue violet. The wonder of their parent 
Edith 
 Wolford is that the interaction appears to not take place and the falls are 
 blue in spite of the fact that yellow is theoretically present in the falls.
>>

I agree.  It's always tempting to oversimply the discussion of pigments, and 
in this case we completely ignored any co-factors.  

<<
 Please take Dr. Werckmeister with a grain of salt. His mechanistic 
 explanations of genetics are often a stretch e.g. the notion that whites 
with 
 a pulp leaf base have a filter of some sort at the base of the flower that 
 prevents purple coloring getting to the flower. Or how about the idea that a 
 cross between a pure dominant and a pure recessive will occasionally produce 
 a seedling in which has somehow gotten four doses of the recessive gene.
   >>

Ahhh....  But that is NOT what Dr. Werckmeister said.  We must be very, VERY 
cautious when dealing with translations because we often get a layman's 
interpretation.  

In one case, Werckmeister cited seedlings which could only be explained under 
the single-gene theory IF they had somehow managed to inherit four doses of 
the recessive gene from such a cross.  This was provided as a 
counter-example, and illustration of an otherwise inexplicable condition that 
his dual-pathway model could handle.  

How deeply do we want to go into this?

Sharon McAllister

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