Hypothetical explanation of genetic color distribution

This is just a simplistic, hypothetical explanation of colours in Ipomoea (Not set in stone, plust there are many modifier, mutable, etc. genes that must be considered).

Source: Morita, Yasumasa (2005) et. al. Japanese morning glory dusky mutants displaying reddish-brown or purplish-gray flowers are deficient in a novel glycosylation enzyme for anthocyanin biosynthesis, UDP-glucose:anthocyanidin 3-O-glucoside-2''-Oglucosyltransferase, due to 4-bp insertions in the gene. The Plant Journal, 42: pp. 353-363.

"The Japanese morning glory (Ipomoea nil) displays bright blue flowers (Figure 1b) that contain the peonidin (3¢-methylcyanidin) 3-O-sophoroside derivative named Heavenly Blue Anthocyanin (HBA) (Figure 1f; Kondo et al., 1987; Lu et al., 1992), and a number of spontaneous mutants exhibiting various flower colors have been isolated since the 17thcentury (Iida et al., 1999, 2004; Imai, 1927). Genetic studies on the color of I. nil have shown that blue flower coloration was mainly controlled by two genetic loci, Magenta and Purple (Hagiwara, 1931; Imai, 1931). Recessive magenta and purple mutants bloom magenta and purple flowers, respectively, and double mutants carrying both magenta and purple alleles display red flowers (Figure 1d).... Among the various colors of I. nil flowers, the most favorite hue for Japanese floriculturists has been reddish-brown or purplishgray petals (Figure 1c,e) since the early 19th century, and the flower coloration is caused by recessive dusky mutations (Hagiwara, 1956; Imai, 1931)....Although their flower coloration may subtly vary due to various genetic backgrounds, the dusky mutants carrying the wild-type Magenta allele generally exhibit bluish or purplish-gray flowers that contain cyanidin derivatives, whereas those with the magenta mutation tend to display reddish-brown flowers that contain pelargonidin derivatives, as represented in Figure 1(c,e). Among them, Magenta plants with the wild-type Purple or Purple-revertant allele show a tendency to produce more bluish-gray flowers than those with the purple mutation. Similarly, magenta mutants with the Purple or Purple-revertant allele generally exhibit darker reddish-brown flowers than those with the purple mutation."
Taken from Morita (2005) pg. 355

According on the quote above, Ipomoea nil alleles are as follow:

Mg = wild-magenta
Pr = purple
mg = recessive magenta
pr = recessive purple

DY = Dusky
dy =dusky

Genotypes with DY mutation:

MgPr = Blue blooms.
Mgpr = Purple blooms
mgPr = Magenta blooms
mgpr = Red blooms

Genotypes with dy mutation (this includes dy-1 and dy-2; see http://davesgarden.com/community/forums/fp.php?pid=5683018):
MgPr = Darker blueish-grayish-purplish blooms.
Mgpr = Lighter blueish-grayish-purplish blooms.
mgPr = Darker reddish-brown blooms.
mgpr = Lighter reddish-brown blooms.

This message was edited Oct 18, 2008 3:22 AM

This message was edited Oct 18, 2008 3:23 AM

Punett squares for possible filial combinations

Genotypic Ratio based on the punette square (above image)

1. Mgmg x Prpr
25% MgPr
25% Mgpr
25% mgPr
25% mgpr

2. Mgmg x prPr (sorry I made a mistake on the Punette square; lower right quadrant is suppose to be mgPr not MgPr)
25% Mgpr
25% MgPr
25% mgPr
25% mgpr

3. Mgmg x prpr
50% Mgpr
50% mgpr

4. mgmg x Prpr
50% mgPr
50% mgpr

5. mgmg x prPr
50% mgPr
50% mgpr

6. mgmg x prpr
100% mgpr

NOTE**** the probability ratio DOES NOT mean that if you have four seeds from a Mgmg x Prpr (no.1) filial combinations does not mean that you will each get MgPr, Mgpr, mgPr, mgpr genotypic combos for each seeds. The ratio calculates the probability of what kind of genotype you will most likely get for 1 seed. Therefore, for a seed coming from the same filial combination, there is a 25 percent chance of this seed having an MgPr genotype, etc. etc.

This message was edited Oct 17, 2008 8:59 AM

Phenotypes: what colour you will actually see (hypothetically)

1. Mgmg x Prpr
25% (MgPr) Dark bluish gray
25% (Mgpr) Light bluish gray
25% (mgPr) Dark reddish-brown
25% (mgpr) red

2. Mgmg x prPr
25% (Mgpr) Light bluish gray
25% (MgPr) Dark bluish gray
25% (mgPr) Dark reddish-brown
25% (mgpr) red

3. Mgmg x prpr
50% (Mgpr) Light buish gray
50% (mgpr) red

4. mgmg x Prpr
50% mgPr) = Dark reddish-brown
50% mgpr) = red

5. mgmg x prPr
50% (mgPr) Dark reddish brown
50% ( mgpr) red

6. mgmg x prpr
100% (mgpr) red

This message was edited Oct 17, 2008 9:01 AM

Note that Filial combinations no.1-6 are HOMOZYGOUS. We also have to consider HETEROZYGOUS combinations because they could also produce chocolates

Possible Filial combinations of heterozygotes
7. mgPr x mgPr
8. mgpr x mgpr
9. mgPr x mgpr

Genotypic Ratio

7. mgPr x mgPr
25% mgmg
50% mgPr
25% PrPr

8. mgpr x mgpr
25% mgmg
50% mgpr
25% prpr

9. mgPr x mgpr
25% mgmg
25% mgPr
25% mgpr
25% Prpr

Phenotypic Ratio

7. mgPr x mgPr
25% (mgmg) Recessive magenta
50% (mgPr) darker reddish brown
25% (PrPr) Wild purple

8. mgpr x mgpr
25% (mgmg) Recessive magenta
50% (mgpr) red
25% (prpr) Recessive purple

9. mgPr x mgpr
25% (mgmg) Recessive magenta
25% (mgPr) darker reddish brown
25% (mgpr) red
25% (Prpr) Heterozygote purple

NOTE: For recessive magenta (mgmg), recessive purple (prpr), wild magenta (MgMg), wild purple (PrPr), heterozygote magenta (Mgmg) and heterozygote purple (Prpr), colours are not addressed as of yet; I cannot find comparisons/studies for these combinations.

To sum it up, these are the combinations that will probably produce a chocolate or reddish tint in your mgs..

1. Mgmg x Prpr
25% (MgPr) Dark bluish gray
25% (Mgpr) Light bluish gray
25% (mgPr) Dark reddish-brown
25% (mgpr) red

2. Mgmg x prPr
25% (Mgpr) Light bluish gray
25% (MgPr) Dark bluish gray
25% (mgPr) Dark reddish-brown
25% (mgpr) red

3. Mgmg x prpr
50% (Mgpr) Light buish gray
50% (mgpr) red

4. mgmg x Prpr
50% mgPr) = Dark reddish-brown
50% mgpr) = red

5. mgmg x prPr
50% (mgPr) Dark reddish brown
50% ( mgpr) red

6. mgmg x prpr
100% (mgpr) red

7. mgPr x mgPr
25% (mgmg) Recessive magenta
50% (mgPr) Dark reddish-brown
25% (PrPr) Wild purple

8. mgpr x mgpr
25% (mgmg) Recessive magenta
50% (mgpr) red
25% (prpr) Recessive purple

9. mgPr x mgpr
25% (mgmg) Recessive magenta
25% (mgPr) Dark reddish-brown
25% (mgpr) red
25% (Prpr) Heterozygote purple

Here's a chart from the same journal article again. Note that the Dusky allele (DY) works along with Mg, mg, Pr, and pr alleles. If you look/compared the colours, dy-1 and dy-2 (false persimmons) "dilutes" the colours from DY...this is another story though

This message was edited Oct 17, 2008 10:31 AM

Please let me know if i've made mistakes and I would appreciate it if any of you have inputs/comments/suggestions

Eliz =D

Was it easy to get the 1931 publications of Hagiwara and of Imai?

Hi Joseph,

I didn't get the publications of Hagiwara and of Imai, the author Morita quoted Hagiwara and Imai. this article by Morita I found online.

I did borrow a book from my campus, with a 1903 publication by Imamura and Shun-ichiro titled Physiology of flowering in Pharbitis nil. It was old and dusty hehehe and smelled funky hehehe. It talked about exposure to light and the "dark period". I'll look at Morita's references/bibliography and see if I University of Toronto libraries have them...Thank you for the heads up =). Hopefully we can get more info on Ipomoeas/hybridizing.

Eliz, I have to get back to this - just want to thank you for doing this for now - I've been curious about genetic underpinnings to what we can see - my crystal ball says there are oodles of grow-outs in the future of this forum, thanks to your posting this.

Maybe from this hypothetical(?) genetic coding of color, we could explore what else might link up with these gene/phenotype relationships and thus better understand Dr. Yoneda's gene linkages here - http://protist.i.hosei.ac.jp/Asagao/Yoneda_DB/Images/PCD4764/D/14.jpg -- but that's putting the cart before the horse...don't mind me...it's just that I. nil is not known to self-sow over the winter here, but one of Emma's grays certainly did this past year; so who could help wondering if there's something special about Emma's grays that the other nils don't have with respect to self-sowing kind of winter hardiness?

For those with rusty science skills (including me), I think Wikipedia is great because of the way each term is highlighted so you can click on it to get a definition in plain English. So, as an aid to following evr's threads, try this:

http://en.wikipedia.org/wiki/Botany
scroll down to "Scope and Importance of Botany" and click on the word, genetics
There are some great charts on the genetics webpage that illustrate what evr is referring to at a glance.

well, a frost is coming and I'm losing daylight - thanks again, Eliz

Have to edit all my entries..I did something wrong: Mg and Pr work together but located at two different loci...which changes the whole story.....

Note to interested MG afficianados - Eliz has rewritten this thread to a revised version here: http://davesgarden.com/community/forums/t/914303/

Thank you bluespiral for the link =).