"Discus Genetics and Breeding Info and Discussion"

[James Yangzon]

there is what you learn in books vs what you learn in practice.

Definitely agree on this one Rick.

This is why I am always careful to note in every comment I made that it is only a suggestion as I have no opportunity of validating it yet, (I have yet to have a pair from my six month PB and bd).

With this I am grateful that guys like you and Rod, and the frequent forumers here and on the other thread, share their breeding experiences freely as it really helps newbies save a year or two in their breeding projects.

[nc0gnet0]

With this I am grateful that guys like you and Rod, and the frequent forumers here and on the other thread, share their breeding experiences freely as it really helps newbies save a year or two in their breeding projects.

I share my breeding crosses (much to the dismay of some others ) quite frequently. I suggest you take a look at my contest threads as well as my homesteader section.

Rick

[James Yangzon]

If I understand you correctly, what you are trying to say is that in my examples of what I call heterozygous expression of the bd gene, everytime I have noted such expression of the BD gene in heterozygous form, your asking isn't it possible that what I am seeing is not heterozygous expression, that in each case the non bd partner was carrying a reccissive hidden BD gene, thus making the examples I have posted in fact homozygous.

We're on the same page now Rick.

the odds that I just by chance have gotten several non blue diamond fish that just "happen" to be carrying the Bd gene very very slim.

The chance may be slim or may be not. It is better to speculate on percentages if we have accurate info on who or what is the parents of the supposed fishes (snow white and rose red) you have given as an example.

if this were the case, we would see many examples of two non blue diamond fish bred together and producing Bd offspring.

Here I cannot comment. I have no experience yet on discus breeding. And so we will just let other experienced breeders have a take on this.

[Rod]

Rod,

I am not saying the fish is a blue diamond - strain

What I am saying is the the blue diamond gene is being expressed, causing the blue peppering in the fish. For instance if the fish had a recessive golden or albino gene (both reccessive), it would not show a hint of either albinism or golden.

I think the blue peppering is being caused by the combination of the pb gene interacting with the multigenic blue coloring, Blue coloring in itself is not a defining feature of the blue diamond imo. There are many blue discus types that are not blue diamonds for example.

But then again a fish homogenous for the BD gene is not neccessarily a BD either. for instance:



Here we are seeing the results of a BD crossed with a Dark Angel, the cross did not result in any typical Blue diamonds (strain) and 100% of the progency turned out like this (there are two shades of blue however). It is interesting to note however, that over time a heterozygous BD fish lightens in blue coloration while the exact opposite happens with a fish that is homozygous for the BD gene.

I disagree with this. The dark angel is a blue diamond, that also happens to be a pigeon blood.

In other words, I think that the Blue diamond (strain) is both the combination of a homozygous blue diamond gene and the refinement/aligment of other polygenetic taits as well giving it a solid blue appearence.


Rick

My arguement is that it is the blue diamond gene itself that causes the solid coloring in the fins. My reasoning is that no other strain has produced such pure solid color despite selective breeding, and that this solid fin color must be caused by mutation rather than selection.

[Rod]

NO

Rod, isn't there a classification for a gene that is not totally reccessive, nor totally dominant? Or is your definition of "reccessive" different than mine? When I thik of reccessive, I think of a gene, that in its heterozygoous state, has to effect on the appearence of the fish. The albino and golden gene are classic examples of this. However, the BD gene and perhaps the ghost gene (have not worked with this one enough) seem to have some bearing on the fish's appearence in heterozygous form.

Another example of a fish that is heterozygous for the BD gene:





Now, there is a whole lot going on with this fish, BD recessive, SS reccessive, and quite possibly ghost reccessive as well.

Rick

Rick, I don't think the term dominant and recessive are preceeded by a superlative. They are already absolute terms and not subject to gradation. I like to think of single gene mutations as on/off switches, and in the case of recessives, an additional position i call standby. (still off, but primed)

[Rod]

I share my breeding crosses (much to the dismay of some others ) quite frequently. I suggest you take a look at my contest threads as well as my homesteader section.

Rick

No dismay here. I love your breeding experiments. The information and knowledge to be gained by experiments is far greater than doing boring old rational breeding.

[nc0gnet0]

I disagree with this. The dark angel is a blue diamond, that also happens to be a pigeon blood.

Ok then what is a mercury? I have a mercury that I believe is heterozygous for the BD gene, it's the only way to explain the offspring I see in my contest batch three. I have witnessed hat the BD gene and the PB gene do interact together sometimes with suprising results, it has me making some guess's as to there relative proximimity.

Blue coloring in itself is not a defining feature of the blue diamond imo. There are many blue discus types that are not blue diamonds for example

.

True, but it's distrubution is usually somewhat different. Rod, take a look at the many crossing of the VR/RC type to a blue diamond. You will see the blue coloring in the prodigy. I have yet to see an expample of such distrubution of the blue coloring over the brown body produced by anyother fish other than a Blue Diamond. It leads me to beleive that it is in fact the BD gene expressing itself in heterozygous form. If not, how do you explain it?

This is not quite what I was looking for but an example none-the-less:



If not a bd gene in heterozygous form, how do you explain the coloration on some of these fish?

Rick

[Rod]

Ok then what is a mercury? I have a mercury that I believe is heterozygous for the BD gene, it's the only way to explain the offspring I see in my contest batch three. I have witnessed hat the BD gene and the PB gene do interact together sometimes with suprising results, it has me making some guess's as to there relative proximimity.

.

True, but it's distrubution is usually somewhat different. Rod, take a look at the many crossing of the VR/RC type to a blue diamond. You will see the blue coloring in the prodigy. I have yet to see an expample of such distrubution of the blue coloring over the brown body produced by anyother fish other than a Blue Diamond. It leads me to beleive that it is in fact the BD gene expressing itself in heterozygous form. If not, how do you explain it?

This is not quite what I was looking for but an example none-the-less:



If not a bd gene in heterozygous form, how do you explain the coloration on some of these fish?

Rick

A mercury shares the same single mutations as a dark angel. The difference in phenotype is explained by multigenic traits, in other words the selection criteria of the respective breeders. I don't think the pb gene is close to the bd gene, because when taken seperately and together, they each still follow basic mendalian inheritance rules. If they were linked on the chromosome, then when bred together, we should see a pattern of distribution not conforming to basic mendal genetics.

In the VR/bd het's example, i think this is explained by a reshuffling of muligenic traits. To go back to my earlier example of 10 genes that switch on or off to control a particular trait (muligenic), for arguements sake i will assume that all 10 are in the on position for blue, and all are in the off position for the vr. When this trait is combined you will get a reshuffling of these 10 genes. Each individual fish will receive a pattern of on or off on each of these alleles. If only one is on, a small amount of blue shows, 5 on gives more blue coloring while 10 on gives a lot of blue coloring. But it will not remove the pattern in the fin edges, no matter how many of these genes are turned on.

I know the above is very much oversimplified, for example it is my belief that the vr could well have some of the blue genes switched on, but is being masked by the dominant gene that controls the expression of blue color. This gene i also believe is not located close to the blue coloring gene and they work independently of each other, so if this is the case it makes no difference how many color genes are switched on, the result will be the same. Its when we cross it and the dominant "no pattern" gene is in heterozygous form, we appear to get some blending of the traits not unlike the white heterozygotes we are more familiar with. This probably suggests some form of codominance in heterozygote vr's, but i don't think it shows the bd gene itself is actually involved in the distribution.

Rod

[nc0gnet0]

A mercury shares the same single mutations as a dark angel. The difference in phenotype is explained by multigenic traits, in other words the selection criteria of the respective breeders. I don't think the pb gene is close to the bd gene, because when taken seperately and together, they each still follow basic mendalian inheritance rules. If they were linked on the chromosome, then when bred together, we should see a pattern of distribution not conforming to basic mendal genetics.

What if they were different mutations of the same allele, one dominant and one reccessive? Not saying this is the case, but curious what we would see. It does seem to stand to reason that certain allelles might be more prone to mutation than others.

There does seem to be some interaction when the two mutations are combined (pb and BD), not that they are linked, but rather the two interact with each other on some level. The Dark angel and Mercury are perfect examples of this interaction. We know when we cross a pigeon blood with a non pigeon blood, most often the resultant offspring are heavily peppered fish, and the pepper is black. However, when we cross a pigeon blood with a blue diamond, quite often this pepper is no longer black, but blue.

Now if this phenomenom that I am described has nothing to do with the BD gene, but rather the carefull alignment of other polygenic traits, would'nt it stand to reason that we would see if happen with other solid colors that were carefully aligned through years of selected line breeding as well? A fish with red, yellow, or orange pepper?

So, if I understand you correctly, what you are saying that the BD gene has nothing to do with this, even though I can show you several cross's either I or others have done, each with the BD gene in a heterozygous state, and that has nothing to do with what I am seeing? I can think of no such examples that exist without the existance of the BD gene, but if what your saying is correct, one would think there should be several.

[nc0gnet0]

Rod,

I finally found the thread to which I was refering, it is located here:

http://forum.simplydiscus.com/showth...bies-look-like

[James Yangzon]

No dismay here. I love your breeding experiments. The information and knowledge to be gained by experiments is far greater than doing boring old rational breeding.

Agree with Rod here Rick.

The experimental breeding you are into will prove valuable not only at present, countless breeders and genetecists will used the data gathered in your breeding projects to validate existing theories or to simply gain more insights into this difficult subject.

Keep the fire burning. . .

[Rod]

What if they were different mutations of the same allele, one dominant and one reccessive? Not saying this is the case, but curious what we would see. It does seem to stand to reason that certain allelles might be more prone to mutation than others.

I don't think that is impossible, but it does seem unlikely to me. Mutations are exceedingly rare, and for it to happen on the same pair of alleles twice in the last 20 years is not something i have considered. I'm not sure how many base pairs a fish has, but i know humans have over 3 billion of them along with about 20 odd thousand genes, and a higher animal like a fish probably have a similar amount. But you are correct, some areas of the genome seem to be more prone to mutation, than other parts.

There does seem to be some interaction when the two mutations are combined (pb and BD), not that they are linked, but rather the two interact with each other on some level. The Dark angel and Mercury are perfect examples of this interaction. We know when we cross a pigeon blood with a non pigeon blood, most often the resultant offspring are heavily peppered fish, and the pepper is black. However, when we cross a pigeon blood with a blue diamond, quite often this pepper is no longer black, but blue.

True, there does seem to be an interaction causing a unique phenotype. It does however defy Mendals observation that only one phenotype is expressed when crossing with 2 homozygous genes. The bd gene should be completely silenced by the homologous and dominant wild gene from the pb. I think because the defining traits of bd are not expressed (patternless fin color), then the reason for this unique phenotype you observe needs to be explained in a different way.

Now if this phenomenom that I am described has nothing to do with the BD gene, but rather the carefull alignment of other polygenic traits, would'nt it stand to reason that we would see if happen with other solid colors that were carefully aligned through years of selected line breeding as well? A fish with red, yellow, or orange pepper?

Perhaps the red, yellow and orange colors, because of the fact that they are on a different dermal layer to blue color, interacts with the pepper in a different way.

So, if I understand you correctly, what you are saying that the BD gene has nothing to do with this, even though I can show you several cross's either I or others have done, each with the BD gene in a heterozygous state, and that has nothing to do with what I am seeing? I can think of no such examples that exist without the existance of the BD gene, but if what your saying is correct, one would think there should be several.

I have bred and crossed the blue diamond a few times over the years (not with mercury/dark angel however) and it has always acted in a recessive manner from what i can tell. If it did interact as you suggest, then by definition it is a dominant gene or perhaps controlled by multiple genes. I shall give this more thought, and add on if i have any further ideas.

[nc0gnet0]

True, there does seem to be an interaction causing a unique phenotype. It does however defy Mendals observation that only one phenotype is expressed when crossing with 2 homozygous genes. The bd gene should be completely silenced by the homologous and dominant wild gene from the pb. I think because the defining traits of bd are not expressed (patternless fin color), then the reason for this unique phenotype you observe needs to be explained in a different way.

Ok, now we are getting on the same page

Sometimes I struggle to but into the right words/terminology, what I am trying to get across. There does seems to be some interaction, trying to explain it correctly is hard. Although you have not siad it directly, are you saying the blue diamond possess's two gene mutations, both the BD gene and a "patternless gene". I always thought the BD gene did both, and it was a single mutation.

As for the explanation of the blue coloration being on a different dermal layer, this is interesting and something I have considered, but there has to be more to it than just that, otherwise it would seem that a blue turq crossed with a pigeon blood might express some of the same color shift we see with the BD when crossed with the same pigeon blood. Unless, blue is a color that can happen on multiple dermal layers......

Rick

[James Yangzon]

Hi Rod and Rick,

Bit dizzy, information overload I guess. You got a flurry of posts here that leaves a newbie like me scratching my head as I look into the ceiling. And I have to beg for some patience as I try to situate the issues in a newbie perspective.

1. What is peppering? Is my understanding correct when I say that peppering is some kind of sprinkling of color, a different one, from the base color of the fish? (Is this redundant because you cannot see any peppering if the peppered color is the same as the base color?) So if the base color is white or red or blue, we might see a black peppering.

2. How do we described a pigeon blood mutation? Is the peppering exclusive only to PB gene? Aside from peppering, what are the characteristics of a PB gene?

3. What are the defining characteristics of a blue diamond?

TIA guys.

[bornlooser]

Very interesting and educational stuff...half of which is hard for me to digest.. but keep it coming ...lol.