"Discus Genetics and Breeding Info and Discussion"

[nc0gnet0]

- And now the most secret iridophores. I believe that they are present in PB, but because of lacking melanophores below them, their ability of iridescence and reflection is touched somehow and ability to reflect light is shifted to higher wave length.

Tomas, sometimes I am not quite sure I am following you completely with what you are trying to say. I think it is more of a language thing more than anything else. so bear with me here.......

I agree with you completely on the fact an iridophores appearence will be altered by any underlying chromotophores. This is due to the fact that they are the most trasparent of all the chromotopores and will take on (as far how they appear) the basic color of the chromotophore beneath them. for those people out there struggling with the terminology (and my bad spelling), think of iridophores as the clear coat you put on your car after you paint it. But in your example of the pigeon blood, I can assure you they are still there, at least sometimes. One of my cross's is a classic example of this, with the iridophores lying over the top of both white (leucophores) and orange (erythrophores).

[nc0gnet0]

- BD can darken little bit and pepper especially keeps normal melanophores function (hormonal or environmental reaction) – it shows us that defect in melanophores is not complete (in Albinoss for example, we can see complete lack of melanin and no melanpohores at all).

Well I wasn't going to go there just yet, but sense you touched on it.....

First of all in Discus, albinism is a bit of a hot topic. Even more controversial than the pb. Are they even albino's? Not in the classic sense because they obvioulsy do have chromatophores (ie red albino's, yellow albino's) but what is interesting is the lack of blue albino's(ie no cyanophores), and the lack of pepper (melanophores-brown/black).

Why is this?

The albino gene is not 100% penetrant, ie: it doesn't appear to effect all layers of the dermis. It would appear then that cyanophores and melanophores occur in the lower layers of the dermis, while the light colored chromatophores lie on top of them. This stands to reason as vice versa would not make any sense at all. I understand that albinism effect the production of melanin, but why is it also effecting the production of the blue cyanophores as well? Ever see a albino blue diamond? It's not blue.....

Here we seem to see a crack in Mendall's principles......or do we? We need to remember that Mendal studied peas, the rules change a bit in cold blooded animals, or at least appear too.

Perhaps in some mutations wether or not it is in heterozygous form or homozygous form, to some degree effects its level of penetration throughout the dermis? I have sworn, (but cannot prove) that the inclusion of one albino allele (ie heterozygous) in a pb to non pb cross, has lessed the degree of pepper in the resultant f1 offspring. How can this be?

Another question to ask is, can a mutation appear as dominant in the lower regions of the dermis, yet reccesive in the upper regions? Is this possible? If not, why?

If we have a dominant mutation, thats penetrance is effected by whether or not it is in heterozygous or homozygous form, wouldn't it be easy to misclassify it?

[James Yangzon]

Is it stress bars or mood bars?

Does the bars appear only when they are stress? Or they also appear on other occasion such as it is more accurate to call them mood bars?

TIA

[tomas_ch1]

Tomas, sometimes I am not quite sure I am following you completely with what you are trying to say. I think it is more of a language thing more than anything else. so bear with me here.......

I agree with you completely on the fact an iridophores appearence will be altered by any underlying chromotophores. This is due to the fact that they are the most trasparent of all the chromotopores and will take on (as far how they appear) the basic color of the chromotophore beneath them. for those people out there struggling with the terminology (and my bad spelling), think of iridophores as the clear coat you put on your car after you paint it. But in your example of the pigeon blood, I can assure you they are still there, at least sometimes. One of my cross's is a classic example of this, with the iridophores lying over the top of both white (leucophores) and orange (erythrophores).

Rick, sorry for my language. This topic is quite tough exam for my English. Another source of confusion may be our different understanding of Blue color in Discus fish. In my view I disregard the cyanophores. As far as I know it was found out that they are extremely rare in fish. They were described in Mandarin sea fish (Synchiropus splendidus), and may be in few other species, but otherwise it seems to be exemption of form production of blue colour. Contrary most of blue in fish (and reptiles, butterflies etc) is caused by iridophores. For example, blue stripe in neon tetra comes from iridophores, blue in guppies comes from iridophores, blue stripes in Danio rerio, blue in Betas, etc. –it all comes from iridophores. I am not aware of study in Discus species, but it seems to me very improbable that blue in discus would be caused by cyanophores.
(For others reading it. Difference between those two types of chromatophores is quite huge. Blue in cyanphores comes from pigment, i.e it is very similar to creation of red, yellow and black in discus), whereas blue form iridophores comes from reflection of light of specific wavelength. Google for Structural coloration)
Now if you will have a second look on my definitions of BD or PB I think we may have closer view. Every time I was mentioning iridophores, I was thinking about turquoise(blue) patterns of discus fish. I fully share your opinion, that missing layers under iridophores cause altering their appearance. But I do not thing they are transparent. In my example of PB I believe their reflection ability is changed and we see patterns rather white to violet. The fact they may appear bluish also in PB (top dorsal, end of fins) may be caused by the areas where some remaining melanophores persist.
Tomas.

[tomas_ch1]

- First of all in Discus, albinism is a bit of a hot topic. Even more controversial than the pb. Are they even albino's? Not in the classic sense because they obvioulsy do have chromatophores (ie red albino's, yellow albino's) but what is interesting is the lack of blue albino's(ie no cyanophores), and the lack of pepper (melanophores-brown/black).

Why is this?

Albinism. My laymen’s understanding is that there is lot of definisions of albinism, but the most accepted one is the complete impossibility to synthesize melanin. I believe that it is exactly what we see in Albino mutation of discus fish. One single gene mutation. Nothing else is impacted just no melanophores (or maybe ther are melanophores but without melanin). There are none in the skin none in the eyes, nowhere. Your ARSG is came to my mind as perfect example. It can synthetize, red, orange yellow, it can produce patterns etc. And blue? I agree with you that it is still there, just like in PB, but reflection is changed dramatically and we see rather whitish patterns instead of blue. No brown/black obviousely.

[tomas_ch1]

Hi James,
Stress or mood. Two names fo the same thing James. Yes, they use it for breeding, hiding and other behaviour, so mood bars may be more accurate. What is interesting form genetic point of view, that all mutation Rod mentioned in the list of mutation few pages back, in fact influence the stress bars.....
regards Tomas

[nc0gnet0]

Albinism. My laymen’s understanding is that there is lot of definisions of albinism, but the most accepted one is the complete impossibility to synthesize melanin. I believe that it is exactly what we see in Albino mutation of discus fish. One single gene mutation. Nothing else is impacted just no melanophores (or maybe ther are melanophores but without melanin). There are none in the skin none in the eyes, nowhere. Your ARSG is came to my mind as perfect example. It can synthetize, red, orange yellow, it can produce patterns etc. And blue? I agree with you that it is still there, just like in PB, but reflection is changed dramatically and we see rather whitish patterns instead of blue. No brown/black obviousely.

If we strictly adhere to the definition of albinism in discus as the complete lact of production of melanin, then there is no reason that we should not see an albino discus with blue coloration. There are however plenty of examples of blue coloration on a white base, so the production of blue coloration in discus does not depend on an underlying darker base color.

As for the existance of cyanophores in Discus, you are correct, cyanophores are rare but they do exist. As to whether or not they happen in discus I am not sure of, but if they don't, then what we ae probably dealing with more than one type of iridaphore. For the sake of discusion I refer to them now as cyanophores.....

As for structural coloration, that is another topic altogether, is somewhat rare, and I am not aware of an example of it occuring in "living" tissue. Structural coloration is quite different than color layering.....maybe you made a mistake in your reference?

But I do not thing they are transparent.

Maybe I would have been better served if I called them "semi-transparent", I will grant you this.

Rick

[James Yangzon]

Hi James,
Stress or mood. Two names fo the same thing James. Yes, they use it for breeding, hiding and other behaviour, so mood bars may be more accurate. What is interesting form genetic point of view, that all mutation Rod mentioned in the list of mutation few pages back, in fact influence the stress bars.....
regards Tomas

Hi Tomas,

I actually notice Rod refer to it as mood bars and I realized he may be in for something as I have observed that the bars appear in different occasions other than being stressed. To be more accurate I will now refer to it as mood bars.

If all single gene mutation has influenced on these mood bars, does it mean that all monogenetic deviations affected the melanin from the different stages of its creation?

TIA

[James Yangzon]

Rick, sorry for my language. This topic is quite tough exam for my English. Another source of confusion may be our different understanding of Blue color in Discus fish. In my view I disregard the cyanophores. As far as I know it was found out that they are extremely rare in fish. They were described in Mandarin sea fish (Synchiropus splendidus), and may be in few other species, but otherwise it seems to be exemption of form production of blue colour. Contrary most of blue in fish (and reptiles, butterflies etc) is caused by iridophores. For example, blue stripe in neon tetra comes from iridophores, blue in guppies comes from iridophores, blue stripes in Danio rerio, blue in Betas, etc. –it all comes from iridophores. I am not aware of study in Discus species, but it seems to me very improbable that blue in discus would be caused by cyanophores.
(For others reading it. Difference between those two types of chromatophores is quite huge. Blue in cyanphores comes from pigment, i.e it is very similar to creation of red, yellow and black in discus), whereas blue form iridophores comes from reflection of light of specific wavelength. Google for Structural coloration)
Now if you will have a second look on my definitions of BD or PB I think we may have closer view. Every time I was mentioning iridophores, I was thinking about turquoise(blue) patterns of discus fish. I fully share your opinion, that missing layers under iridophores cause altering their appearance. But I do not thing they are transparent. In my example of PB I believe their reflection ability is changed and we see patterns rather white to violet. The fact they may appear bluish also in PB (top dorsal, end of fins) may be caused by the areas where some remaining melanophores persist.
Tomas.

Again, I am glad to note that one of the two main components of how to accurately isolate the effect of the single gene mutations in the fish or Discus is now being explained Tomas.

Allow me to always take the perspective of the newbie (as I am in terms of breeding), so my queries may sound elementary to you but it always help to go back to the basics.

Is it possible to categorized what color in Discus is real (or those produced through pigments) and those that is 'seen' because of specific wavelength of light or combination of other environmental factors other than the pigment? (You correctly call this structural coloration)

Can these color be further categorized into 'melanin family pigments' and is there any 'family pigments' other than the melanin? I was thinking about reds, yellows and orange, what are they called if we are going to categorized them?

I believe, IMHO, that if approach this way, we can now more or less situate the more technical discussions on chromatophores and how single gene mutations affect their interactions.

[nc0gnet0]

Is it possible to categorized what color in Discus is real (or those produced through pigments) and those that is 'seen' because of specific wavelength of light or combination of other environmental factors other than the pigment? (You correctly call this structural coloration)

I beg to differ, in the context we are talking about, structural coloration is not correct. While there are indeed some examples of structural coloration, for instance a peacock's feather, I am unaware of any such examples of it's existance in living tissue(in animals), not to mention it's existance in conjunction with pigmentation.

[James Yangzon]

I beg to differ, in the context we are talking about, structural coloration is not correct. While there are indeed some examples of structural coloration, for instance a peacock's feather, I am unaware of any such examples of it's existance in living tissue(in animals), not to mention it's existance in conjunction with pigmentation.

As always Rick, I am indebted to the body of knowledge you are bringing to this Forum.

Just a quick clarification, it is common knowledge that structural coloration plays a big part in the creation of color in birds, specifically, parrots. Blue in parrots is a result of structural coloration, and in this manner green. Green is a result of blue structural color plus the color yellow (psittacine pigment), a trick of the eye (light of course) so to speak.

I was thinking there might be similarities in fish. Nevertheless, I am aware that structural coloration is part of many cephalopods, so I guess they count as an example of living tissue in animals.

Anyway, for proper information for us newbies, where can we access scientific studies of chromatophores interaction specifically in Discus?

God bless

[nc0gnet0]

Anyway, for proper information for us newbies, where can we access scientific studies of chromatophores interaction specifically in Discus?

To my knowledge there is none, if you happen upon any let me know.

Just a quick clarification, it is common knowledge that structural coloration plays a big part in the creation of color in birds, specifically, parrots. Blue in parrots is a result of structural coloration, and in this manner green. Green is a result of blue structural color plus the color yellow (psittacine pigment), a trick of the eye (light of course) so to speak.

Yup, but those are occurring in feathers, which is the equivallent of hairs, etc. and they are not depending on pigmentation AND stuctural coloration. Which brings us to....

Nevertheless, I am aware that structural coloration is part of many cephalopods, so I guess they count as an example of living tissue in animals.

Octipi and squids, etc. Definitely unique, still being studied, and an exeception, not the rule. Until proven otherwise, I think we should stick with pigmentation and the production of it, rather than make an assumption the discus depends on structural colorationg rather than color layering.......

Rick

[James Yangzon]

Yup, but those are occurring in feathers, which is the equivallent of hairs, etc. and they are not depending on pigmentation AND stuctural coloration.

Structural coloration indirectly (or even ultimately) depends on pigmentation, melanin in particular. I am talking here about the blue structural coloration in birds. If you are referring to the Discus then I do not have any information whatsoever; as what you have stated, there is no scientific studies that we can count on to.

Octipi and squids, etc. Definitely unique, still being studied, and an exeception, not the rule. Until proven otherwise'

If scientific studies are scarce on the issue of structural coloration on fishes, how can we state absolutely that the structural coloration found in cephalopods is an exception? Isn't it that we can only say that something is an exception to the rule if the rule is already established? Studies are scarce, hence, rule is yet to established.

I think we should stick with pigmentation and the production of it, rather than make an assumption the discus depends on structural colorationg rather than color layering.......

I am not saying that Discus coloration is all structural, I am asking if there are some color like blue, that may be a result of structural coloration.

[QUOTE=nc0gnet0;1021239]To my knowledge there is none, if you happen upon any let me know.

If there is none, and when we hypothesize, does this mean that the system we are adopting is from the study of other fishes and that we are actually making an assumption that what is applicable to other fishes maybe applicable also to Discus?

Thanks in advance.

God bless.

[nc0gnet0]

Bird feathers don't occur in a dermal layer, your spinning this conversation way off track. Stuctura coloration and the known mutations in discus just don't coincide.

[James Yangzon]

Bird feathers don't occur in a dermal layer, your spinning this conversation way off track. Stuctura coloration and the known mutations in discus just don't coincide.

Pardon me Rick, but I have reviewed my previous comments and there is nothing there that I have claimed that bird feathers occur in dermal layers.

Again, I may have not made myself clear enough. Could be a sign of a newbie trying hard to understand technical stuff.

God bless.