Re: Luminata Genetics - Violet Music

Dave, I refer back to the post yesterday labeled "Re: Luminata Genetics (2) irischap."
 
The post contains two quotes from authoritative sources defining the "Luminata" pattern.  This genetic unit is expressed phenotypically as a "Luminata" when and only when it is in relation to another plicata allele, the one for "Glaciata," in a specific ratio.  The Luminata allele is coded "pl-u", the Glaciata as "pl-a" in the literature, the "u" and the "a" as subscripts without the hyphen.
 
Chuck Chapman, in that post, acknowledges that there are a number of other genotypes possible than those for straight plicata of the classic sort, the simple luminata, and the simple glaciata, plus the more recently recognized "zonal" pattern.
 
The four names given above, plus the dominant PL, a self, consist of only five of the numerous sets of variant phenotypes derived from various combinatations of the alleles which share the pl locus that are possible.
 
There are, for example, those genotypes -- or that genotype -- that has the phenotype of  simple plicata plus the fill-in of the areas normally open or non-blue in a plicata with a pattern that is clearly a luminata co-expressed with a plicata.  At one time these were called "plicata-fancies" or "fancy plicatas."  Those terms are no longer used as the genetic origin of the combined patterns is now recognized and understood.  They are referred to as "plicata-luminatas" or the equivalent term reversing the order of the two nouns.  These, however, are never rightly described as "Luminatas."  That confuses the clear definition set forth as quoted in Chapman's post yesterday, referenced above.
 
Anthocyanin distribution is complex and a number of loci in addition to that of the plicata allelic series is involved in synthesis and location of that synthesis (distribution) in the iris plant, including on the rhizome, on the base of foliage, on the stem, on spathes, and on various parts of the inflorescence.
 
We have not begun to identify all the various enzymes and protein catalysts responsible for these various local expressions and their genetic source.  It is not surprising that luminata-like marbling of anthocyanins should appear in a number of patterns other than the classic (strictly defined) "luminata."
 
You have illustrated or pointed to a number of cultivars that do show such marbling.  The marbling alone does not define luminata however.  The glaciata-like lack of anthocyanins on the haft and claw, and in the beard, is definitive also.
 
RING AROUND ROSIE, SPLASHACATA and other varieties show what may prove to be still another plicata allele distinct from plicata.  I also have yet to see described or defined a genetic analysis of the difference between the plicata-made-from-dots, as in the historic BLUE SHIMMER, and the plicata-made-from-lines.  The majority of plicatas seem to have both lines and dots.  It would not surprise me if two different alleles were involved here.
 
A single gene locus such as "Plicata" can contain more than a million base-pairs in the DNA, or be relatively few, as in a few thousands of pairs.  In any case, there is ample room in the "locus" for many variations.
 
Neil Mogensen  z 7  western NC mountains


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