Re: HYB: Gene Color Chart

: Hello Everyone,
:    I am trying to guess what my seedlings will look like and I have a
:couple of questions. An example is a cross between a red self x pink self.
:Does the dominant  I  overide the V and the PL ?

Yes. That's why it's called "dominant".  ;)  (Actually, I shouldn't be
flip. It's not altogether obvious. But in this case, yes, the presence of I
inhibits the expression of purple pigment, no matter how many Vs are
present.)

So expect at least half the seedlings to have the violet inhibited, perhaps
more than half. Red self x pink self would generally produce yellow selfs.

 Another question is how
:many xxx's does the offspring end up with? On the chart there are 5 for the
:red and 3 for the pink. Which 4 genes do they end up with?

You can't be sure. Since my "x" stands for "at least one", all that you
know is that it is _possible_ for this gene to be passed on to the
seedlings. Any of the seedlings _could_ receive any of the five x's the red
has, and _could_ receive any of the 3 x's the pink has. Whether any
individual seedling actually receives a particular gene or not is a matter
of random chance, influenced by the number of copies of that gene that the
parents have. But as I said in the section "When You Cross 'Em", if one
parent has the gene, expect at least half of the seedlings to have it,
possibly many more than half. Also note that unless there is a "o" for some
particular gene in the chart, the iris may very well carry it. We just
can't say. The pink self, for example, may very well have both V and PL.

Here's the cross of red self x pink self:

                V   I   Is  Y   H   A   T   PL  pl  pl-lu

red self        x   o   o   x   o   x   x   x

pink self           x       x   o   x   o

seedlings       +   +       *   o   *   +   +

+ = at least half of the seedlings should have the gene
* = at least 3/4 of the seedlings should have the gene

So there are a lot of possibilities for any particular seedling, they will
not all be the same. The only thing we know for sure is that there should
be no halos. (Actually, we probably don't even know this for sure, because
the genetics of the halo pattern has not been studied very extensively; it
may not be a simple dominant gene.) Each *, +, or blank amounts to "maybe,
maybe not"!

However, there are a few educated guesses we can make. First, "at least
3/4" is something that will be sure to be in evidence in a large number of
seedlings. Hence you won't find many that don't have the Y gene. This means
blues, whites, and violets should be quite rare.

Second, the recessives t and pl are pretty rare--you're only likely to find
them in any significant dosage in irises that have a pink or plicata
parent. Chances are your red doesn't have any immediate pink ancestors, and
neither parent have any immediate plicata ancestors. If this is the case,
the likelihood of the seedlings having T and PL becomes very high, almost
certain (not just "at least half" as the chart suggests). That means no
pink seedlings, no plicata or luminata seedlings. If you find such in the
seedling patch, it's a dead giveaway that your red carries the pink gene t,
and that both carry the plicata or luminata genes pl or pl-lu.

So where does that leave us? Almost every seedling will have yellow pigment
distributed throughout the flower. Many will inherit I, leaving them yellow
selfs. Those that don't get I will probably be red, brown, or blends (they
are very likely to have V). There might be a very small number of whites
and purples too, if some of the seedlings manage to avoid getting Y.

Bottom line: Anything is possible (excepting H, any of the genes in the
table might or might not be present), but the smart money is on yellow
selfs and reddish blends.

Happy irising, Tom.




~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Tom Tadfor Little                   telp@Rt66.com
Santa Fe, New Mexico (USA)
Telperion Productions  http://www.rt66.com/~telp/
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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