a little genetic math

[Hybridfish7]

so there's an old article on one guy's findings in regards to convict genetics but wait wait before you click off because convicts, hear me out
so in the article he established the pink gene is recessive to the normal black
the pink gene is the leucistic gene in convicts (a.nigrofasciata)
however, the leucistic gene in HRPs is platinum
so, as seen in my other posts with nick, he is a platinum, and just a little side info- his parents were marbles, but as a result of that he is not a pure HRP and must have marbled convict genes somewhere down his family tree.
however, in my experience with breeding him, I have found that the blue gene in HRPs cannot combine with the black gene of convicts. What I believe is that the coloration in HRPs is caused by a dominance in iridophores and or guanophores, which gives them that iridescent blue coloration. When most of the pigment is stripped by the leucistic gene, this results in the shiny white "platinum" scales. On the other end of things, convicts don't seem to have this, and rather have a dominance in melanophores, which in bettas, controls the melanistic and cambodian genes (cambodian bettas are fish that are pretty much genetically supposed to have black pigment but don't, which results into a pink/fleshy colored fish) which leads me to believe that the pink coloration in leucistic a.nigrofasciata is caused by their scales having a dominance of melanophores, but the actual coloration being stripped with the leucistic gene.
What I do not understand yet, is why the blue gene cannot combine with the black gene, maybe they're just not dominant over eachother, which results in there being a random split of some fry having the gene and some not. In his first two spawns, there was 4 way split of platinums, pinks, blues and blacks (I got ~150-200 of each color per spawn). His mate is a normal black convict, which for one means she is carrying the leucistic gene, and two, there is technically a 50/50 split with the blue and black, since as I stated before the leucistic version of the black gene is "pink", while the leucistic version of the blue gene is "platinum".
Now back to the whole thing about marbles and the other guy's findings, he found that marble is recessive to black, but dominant over leucistic (and shows up in leucistic fish as a result)
Nick is technically a marble, he has black stripes on his fins (which have faded as he matured and as his colors solidified)
The other post found that the with 0 copies of the marble gene, the resulting fish is just leucistic, with one copy it has light marbling, and two copies it has heavy marbling. In that case Nick has one copy of the marble gene.
Another thing he found was that marble to leucistic produces a split of marbles and leucistics, black to marble produces blacks carrying the marble gene. When the latter was crossed to a pink, they produced a small percentage of marbles, but primarily pinks and blacks. What I don't understand is why none of nick's fry have come out marbled. By the previous logic, it should just be working a bit backwards, as instead of crossing a black carrying the marble gene to a pink, I'm crossing a marble to a black carrying the leucistic gene. By that logic it should just be the leucistic gene interacting with the marble, as the fry are coming out visually pink or platinum, meaning nothing is dominant enough over the leucistic gene for it to not show up in its pure form.
My understanding is, his fry are then at the very least carrying the marble gene, so if I cross his leucistic fry together should they then be genetically capable of producing marbles? Would I need to breed the blues or blacks, since the leucistics would be showing the gene if they had it?

 

[ichthyogeek]

Yeah you're going to have to back up. I don't know who Nick is, or what HRP (Common Name? Sci name?) are. Here's what I think I understand:

• A. nigrofasciata have a color gene for leucistic (pink), which is recesssive to the dominant Wild Type (WT: black)
• In HRP's, the dominant WT gene is also black, but the recessive gene is platinum(please elaborate)
• Nick is probably a hybrid between Convicts and HRPs, who possesses two copies of the recessive color gene (phenotype: platinum)
• There is a gene for blue color in HRPs. It either does not show up, or is masked by Convict WT genes.

Marbles? Have you tried punnett square-ing this? Like, I think it might be easier to just list what genes you're thinking about, and assign standard genetic language to it (ex. color in peas: GG = dominant homozygous green, Gg = dominant heterozygous green, gg = recessive homozygous purple). I think there's something something in the platinum/pink/blue/black spread, but I'm having trouble keeping up with everything.

 

[Hybridfish7]

HRP as in honduran red point, they currently don't have an actual scientific name other than amatitlania sp. "honduran red point" but it is currently recognized that the ones that come out of rio danli are at least their own species.

• A. nigrofasciata have a color gene for leucistic (pink), which is recesssive to the dominant Wild Type (WT: black)
• In HRP's, the dominant WT gene is also black, but the recessive gene is platinum(please elaborate)
• There is a gene for blue color in HRPs. It either does not show up, or is masked by Convict WT genes.

As for this, each species does not have an individual leucistic gene, as far as I know.

This is Nick by the way, as you can see he is a platinum. His mate, if you can see her down there, is a normal black convict. She is carrying the leucistic gene. I have been referring to it as leucistic when referring to the white coloration as opposed to pink or platinum because from what I can tell, both are controlled by the same gene, but when I refer to it as pink I just mean the leucistic gene in a.nigrofasciata, because that's easier than saying "the leucistic gene in a.nigrofasciata". Same thing for honduran red points and platinums. If nick's mate wasn't carrying the leucistic gene, their fry would solely come out as black and or blue. Obviously she isn't a metallic blue, so this leads me to believe that she is solely carrying the leucistic gene she probably picked up from a pink ancestor. The leucistic gene needs two copies of itself to become visual in an animal. Nick has two copies, which make him visually leucistic. His mate as it turns out, is carrying one copy of the leucistic gene. If they were different genes altogether, the fry would come out WT colored and carrying both genes. Also by this logic, if pinks and platinums crossed, they would still produce WT fry. However, since the fry do come out visually leucistic, this means they now carry two copies of the leucistic gene, meaning the "platinum" and "pink" coloration are controlled by the same gene.
To put it simpler, let's reiterate, nick and his mate produce black, blue, pink and platinum fry. Black and pink are the result of a.nigrofasciata pigmentation. Blue and platinum are the result of a.sp."honduran red point" coloration. The fact that there is a variety/usual clean split in the coloration of the fry throughout each batch means blue is not dominant over black, vice versa, and nor can they combine. From what I can see in other species of fish whose scale pigments have been proven to behave this way in combination with certain pigment removing genes, I believe that the WT coloration of each species in question is controlled by different genes, but the leucistic gene is the same between species, which allows platinums and pinks to interbreed and produce more of both when crossed to eachother, because the base genes, blue and black, are not dominant over one another and thus do not interact.