RE: Re: HYB:Pink:out crosses

Betty, the best way to get a handle on "tttt" is to think of "T" as the
normal condition, allowing at least some yellow to be present in a beard
without any red.  The recessive alternate, "t," is probably simply a
defective version of one of the converting enzymes that make beta-Carotene
and alpha-Carotene out of Lycopene.

Please note also that Chuck Chapman has run across another synthesis
sequence that doesn't follow this same track.  There's more than one recipe
for Lemon Pie.

In my earlier post, incidentally, I reversed the information about alpha-
and beta-Carotene.  It is the beta- version that uses one enzyme, the
alpha-Carotene involving two.  My memory of the details got turned around.

In any event, "t" is an enzyme catalyst--but one that isn't doing its job.
It is a complex protein with possibly some other things like sugars or metal
ions or both involved that is supposed to take one end of the Lycopene
molecule and twist it around into a ring.  It fails to do this when a normal
"T" enzyme is absent.  The abnormal version allows the petal and beard to
contain the tomato-pigmented Lycopene (orange-red) to remain unchanged into
the yellow alpha-Carotene.

Apparently the beta-Carotene pigment gets around this defect, allowing for
all the other versions of pink from peach to orange and yellow to occur,
depending on the mix of Lycopene and beta-Carotene in the beard and/or
petal.

"T" is the normal condition, the functional enzyme present.  The recessive
"t" is a broken tool, and if all four of the tools from the four chromosomes
of that set have a broken version, pink happens instead of the normal
yellow.  If any one of the chromosomes has the functional, working version
of the catalyst, yellow results.  Faint traces of Lycopene may occur in the
Tttt version, however.

Does this help?  The realities of the internal chemistry are undoubtedly
more complex than this, and as Chuck points out, are also complicated by how
much "yellow" is present in the first place, and whether violet, blue or
purple is expressed or not, either in petal or beard.

A blue plus orange-tangerine beard results often in a brownish tone, as in
AMBROISIE.  Sometimes the beard is red-purple, more often brownish.  Pale
warm violet tones with tangerine give vivid clear pinks as in some of Dave
Niswonger's blue-pink series, PINK BLUE GENE among them.  These have
blue-bearded whites or blue-whites in their ancestry, including Melvina
Suiter's LADY BLUEBEARD (aka Lady Blue Beard), SWEET ALICE LEE, Loomis'
"Blue Throat," and Thompkins' COURTESY crossed with pinks and inbred for
several generations.

The possibilities of color combinations is marvelous.  But the difference
between Lycopene versus one of the Carotenes present appears to be a fairly
simple one-gene difference--a broken version of an enzyme.

Neil Mogensen  z 7  Reg 4  western NC mountains

---------------------------------------------------------------------
To sign-off this list, send email to majordomo@hort.net with the
message text UNSUBSCRIBE IRIS
Other Mailing lists | Author Index | Date Index | Subject Index | Thread Index