Hypothetical Bristlenose Genetics

Punnet squares apply to each separate pair of genes. So for every egg, you have a punnet square roll for each set of genes depending on what the parents carry. Hence, unless you know the exact lineage of the fish, you probably just don't know (and that's fun!) 

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Once again this is **purely hypothetical.** And probably extremely simplified. I just whipped this up for fun because I like genetics, and it's turned into a bigger project. I figured it might be interesting for some people to give a little perspective on why it's not always clear cut on what colour fry would be the result of any given breeding. 

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In addition, it is known and well documented that contrary to normal evolutionary logic, Longfin is a dominant gene. 

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°Note° Often Type 2 Albino is mixed up with Blue Eye Lemons. For this model I believe the true no-spotted Type 2 Albinos (they don't have blue eyes, and are a washed out pinkish yellows) are in fact coming from the Yellow / White / Green line and getting mixed up. There also appears to be some albinos that only get spots on their heads which may allude to a third type or another gene interaction (may be a het indicator for the G gene?) 

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Punnet Squares rolls happen for the crosses - capital letter is dominant, lowercase is recessive eg. 

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AA x AA = AA 

AA x Aa = 50/50 AA to Aa (reverse for Aa x aa)

Aa x Aa = 50% Aa, 25% AA or aa

AA x aa = all Aa

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So for every set of genes, you do these calculations. Each chance is °per egg° so you are not guaranteed out of 120 eggs that you would have exactly 60 commons and exactly 60 albinos as an example. 

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(I have replaced the recessive yellow gene n with y in the following just for ease of use) 

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There may be a link between YY and WW. 

We know that YY X WW (unrelated parents) creates all yellow fry. 

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This means that the WW fish must have Yy or YY - so it was YYww x YYWW or YyWW. 

When those fry are bred back to each other, they are about 75% yellow and 25% white, and sometimes no-spot greens pop out from this mix. This only means the original yellow parent from the first YY X WW cross did not carry the W gene, so it was indeed YYww.

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If the original white fish was YY, that explains why all of the resulting fry were yellow. However, it does not explain why in the F2 batch, no-spot greens turn up. This must mean that there is still a recessive yellow gene in there somewhere in order to create Yyww fry.

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So the white parent must have been YyWW. 

However, it does not explain why all of the F1 fry come out yellow. Therefore, we could assume that a YyWw fish is also yellow, °hypothetically° explaining the link between the two genes. Something about the two genes reacts to start the reduction of black and red pigment. However, YYWw is also yellow, but Yyww is green, and YYww is yellow.

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So Y and W as recessive genes together are doing some sorcery. This may suggest both are Incomplete Dominant genes that react with each other in some way. Heterozygous White is still producing washed out fish, and Homozygous is producing pure White. These genes may be what's called Co-Dominant, and White cannot exist without Yellow. There may be some involvement with GG going on here as well. 

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Our cross was YYww x YyWW. 

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We got 50% YYWw and 50% YyWw - and this made all yellows. 

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Then for the F2's, we have a 50% chance of Ww, 25% chance of WW and a 25% chance of ww. Fry with the dominant yellow gene still show up yellow without white (YYww) 

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Then with the YY to Yy, we have 50/50 YY to Yy again. 

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The roughly 75% occurrence of yellow fry in the F2 batch also means the F1 fry were Ww but they were also all YY because yellow doesn't show up unless you have both dominant genes. So there is no chance the original white fish didn't have the Y gene. 

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Because this roll is °per egg° this supports the theory that the original white fish must have had a recessive yellow gene because of that tiny portion out of that 25% on the ww's they then have another 50% chance after that to have Yy. They are the green dragons that turn up -- Yyww, because they carry the Y gene but if you go back to the start these fish are ccGG and have their spots switched off. 

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So, what happens if we cross Yyww to YyWw? Does a fish that is YYWw show up white? No, we know this from our first batch, because they were all yellow. 

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But what about a fish that is yyWW? That is the last piece of the puzzle. We need to work out if the white gene depends on the presence of a single dominant Y gene. 

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It is possible that the recessive W gene may be leucism, which tends to show up washed out animals in other species that carry the gene (leucism in this case may need to be "super" ie, need two pairs of the dominant gene but they may still be leucistic if they're Ww) -- which may explain the unusual calicos that turn up occasionally as well as the snow whites that are covered in black spots like dirty reds. YyWw appear yellow - so they have two lots of a gene that is working in a similar way to lighten the colour. 

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So, how does the red gene react with the YyWw mix? Well, this model is based on horses in which the Agouti gene reduces red in particular points on the body. The logic is calicos always tend to lose colour in very similar places. Agouti is dominant over other genes - if you cross a bay horse with a gray one you're going to get chestnut or bay. If you cross a type 2 albino with no spots with a Calico you still get calicos. This does need more investigation but we do know that the word Super in genetics means two lots of the same dominant gene - Super Reds has to mean RR just based on simple logic. 

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So, what needs to happen now? How can we start to prove the theory? 

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There's a few main areas that I want to look at now. 

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In theory, if I am correct about Green turning off the spots (we know it was originally from a hybrid pairing, likely a species with different spots to the normal ones because there is a gene disrupting that normal function) this should produce all yellow fry, GgYyWw. These fry then need to breed back to each other producing a mix of colours but most importantly those GGyyWW fry. Does a "super" version of the white gene result in white fry, or does it entirely depend on the presence of at least one dominant Y gene? Is Green Dragon really just a normal with the GG turning the spots off or is it going to cause a problem when it turns out all the Green Dragons also carry dominant Y genes? 

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Well, we may be a bit closer to the answer. We have Blue Eye Lemon X Green Dragon as another example.

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The fry were ~75% common, and there were a few different shades of lemon/yellow; both more washed out and normal type ones. 

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That must mean the lemon didn't have the GG gene or Gg - but those lemons that were the fry could be Gg. It also means, if lemons turned up, that either the Green or Yellow parent may have White, but the most probable is that Green also had a dominant Y gene. 

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ccGGYyww X ccggYYww 

Or potentially one of the parents had a W as well. 

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So, all the common fry were Gg or Gg, because the spots didn't switch off, and they were also Yy. Now, we know that Yy normally produces common or green fry unless it's combined with Ww, which makes yellow. In the other White X Yellow combination, we didn't get any particularly washed out fry when they were YyWw. This may mean that the hypothesis about Y reacting with G and making a more washed out looking fish (like a Het indicator) is on the right track. 

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What it also means is, yellow is not dependent on green. There would have been green fry if the yellow parent was originally from green parents as the single G would have combined with that of the parent. However, we have another instance where the Green Dragon was also carrying the Y gene...

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This is something I have been contemplating, as Greens are the newest colour. Before them we did have Yellow and White, but we also know the Greens have come from a hybrid pairing. L088 is the best match in terms of just general body appearance and the specific shade of green, but unless somebody analyses the DNA it's a mystery for now. 

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Lemon might not depend on Green but it may be that green and white both depend on yellow... So one copy of Y gives washed out fry so that explains those, but if there were true lemon fry then the green must have also had a Y...

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Type 1: Albino Common. These are quite yellow, and may in fact be Amelanistic (or perhaps Lemon is Amelanism and this one is Xanthism?) They are often imported under the name "Gold." Even as fry, they look quite different. 

Type 2: This is the gene that I believe causes the weaker fry and is more likely true Albinism as the yellow pigment is also reduced. It's subtle, but side by side it's clear they're different colours. These fish also only have spots on their head, and they generally just don't look very yellow and sparkly. We can import these from Europe under the name "Albino." It's always been interesting that they specifically have them under different names. 

Type 3: Double Whammy of Type 2? Or another gene like G... These are the ones I believe are presenting the gene that causes them not to live for very long. I can't find many photos of adults, and in my experience especially if mixed with other colours they don't tend to do too well and struggle to keep well conditioned. Notice these fish do not have spots on the body but the eyes are a very clear pink. These come from both Yellow X Yellow and Type 2 x Type 2 pairings. 

Type 1 x Type 2 produce brown fry. This may give us the answer to this spot cancelling gene, but we need more information. This is what we can assume if the theory is correct about the no-spot gene. 

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If we have CCggAA (Type 1) x ccGGAA (Type 2) then the resulting fry should be CcGgAA. That means that the original theory on my handwritten notes is incorrect, because AA should be cancelling out the Cc. Perhaps albino commons are actually Cc - but then we should have still had albino fry. The dominant Cc gene has created all brown spotty fry and the Gg is recessive and has not switched off the spots.

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If the Type 2 albinos had the same albino gene as the Type 1's, then AA not cancelling out Cc, that doesn't explain why the Cc is Albino in Type 2's but the fry with Cc come out brown. This suggests Type 2 Albino is a different gene entirely. In many online sources, Type 2 Albinos are confused with the Blue Eye Lemons, but it is the weaker washed out pinkish albinos that are also referred to as Type 2 Albinos. 

Pairs of normal Type 1 Albinos can also occasionally throw very weak, washed out fry that look white like Type 3. They often don't grow correctly and don't make it to adulthood. There may be an additional gene at play here that is producing a reaction with the normal albino gene, which we can assume is 'original' normal albinism and not related to xanthism, amelanism or leucism. It may be that we have Albinos (Type 2/3?) Amelanistic (normal) Xanthic (Yellow) and Leucistic (White - but may also be two types of leucism as seen in other animals). Albino is potentially a lethal or inhibiting combination with some of these.

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We know that Yellows, Whites and Reds can all get black spots on them and both the Type 1 Golds and Type 2 Albinos do not. These fish have fully disrupted melanin production. 

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There may be a few different bases instead of for instance GG switching off the spots and YY being a form of leucism. This is, however, the best explanation I have for Red working the way it does though, and why if you cross Calico to most things you get Calico; there are aspects of this I am more confident with than others.

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Yellow X Yellow also occasionally throws Whites. This might support the conversation about Yellow and White being related, as those yellow parents were capable of producing WW fry. However, we don't know why it is such a small percentage - it's similar odds to the no-spot greens turning up in that F2 batch above. That means the parents were probably YYWw or YyWw and only a small number came out YYWW - because we know that YyWw makes yellow fry. 

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What happens when we breed CcGgAA fry together and get CCGGAA plus a bunch of others? This would help to confirm if GG does indeed switch off the CC gene entirely or whether it's depending on another gene. The evidence is starting to suggest that some of the different colour modifiers aside from the common albinos are not dominant over CC or CC genes. 

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We know that if we cross Green Dragons with Super Reds we get all common brown spotted fry. 

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ccRRgg X ccrrGG should have produced ccRrGg which °should° have been Calico fry if that was the end of the story here, so the reds or the greens must have been Cc. There's a dominant C coming from somewhere - I believe it's likely the Green Dragon here and the GG was trumping the Cc, which is interesting because of the following...

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Reds are likely ccRRgg or Cc, and a dominant CC gene trumps the other colours...  Is it possible that both CC and Cc trump the recessive RR RR Red and Calico in any instance? This may explain why first generation fry crossed to the "G" line come out as commons. It appears that Calico and Super Red can only appear when there is a double recessive cc gene.

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Calico X Albino also produces all brown fry in the same way.

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Albino would have likely been CCrrAA, and the Calico would have then logically been ccRraa. So the fry would have been CcRrAa and CcrrAa - not combos that allow for the Calico or Red to turn up if Cc is trumping Rr. Okay, so if we're going down this path, perhaps it's starting to look like there is a connection between G and Y after all... Perhaps if the fish has both G and Y that is trumping any existing Cc...

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When the resulting fry were bred back to each other, then the results were 50/50 Calico to Albino.

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Assuming the parents were CcRrgg, that makes some sense - the resulting fry would have been a mixture of rolls of CC, Cc and cc etc. There may have been a chance for some ccRR fry to turn up, but the odds were slim. Rr can't go over Cc or CC -- RR can't either? So the original C gene from the Green Dragon X Red must have come from the Green Dragon parent and not the red - assuming Rr and RR can't go over Cc or CC. 

Fry from the Albino X Calico breeding (that came out brown) were then bred back to Super Reds. In both instances, the fry were 50% Calico and 50% normal. 

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Super Reds - ccRR - Browns - CcRr or Ccrr

Logically the fry chosen here were likely Ccrr. Remember our punnet squares - Cc to cc is going to give us a 50/50 mix of both. So we got 50% cc Rr fry showing the colour. If the selected parent fish had been CcRr, there would have been a few reds in the mix if this is correct. This is why it's not such a simple answer - you have no idea if that fish is het for that gene until it's been bred!

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Another good example of this is in another case where a Blue Eye Yellow male was bred to a Common Female. 

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The resulting fry were extremely interesting - the majority were common coloured (specifically the lighter yellow spotted kind that's associated with cf. Cirrhosus) but there was a very small number of both a quite washed out Red (almost halfway between red and Yellow) with black dirty-red like spots, and also a few clearly Calico babies. 

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With both parents being longfin, we might assume that there was some influence of other genetics at play here; notably the common female very likely carried the Calico gene. We already know that just the one copy of the Calico gene is needed to create the Calico; we also need a double recessive cc gene to make the other colours show up. 

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So the male was likely ccGGrrYYww

The female was likely CcggRryyww

As a result, a lot of the fry inherited a dominant C gene which didn't allow the colour morphs to turn up. 

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The fry that came out Calico were ccGgRrYyww. Now, we could also assume that perhaps the female was in fact carrying a single Y gene. The post plausible explanation for the washed out reddish yellow fry with a few Calico spots is that there was some sort of interaction happening with the red and yellow gene. This is supporting the theory that Calico and Red are modifiers that produce a mask-like effect. It also supports the theory that a single Y can also produce a muted effect. 

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So if the female was CcggRrYyww, then with the father having a dominant YY paid, some of the fry would have then indeed been ccGgRrYyww. The theory is starting to come together and work for different case studies. We must find more!

 

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Does Red "Agouti" cancel out White, which seems to cancel out everything else? 

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There are Albino Green Dragons. Whether they're genetically the same as albino versions of the Blue Eye Yellows that turn up though, the ones with no spots, remains to be seen. We know a double whammy of the Type 2 Albino gene produces very weak looking, pale pinkish "fake snow whites" that often don't make it to adulthood.

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Green Dragons x Type 1 Albinos produces a mixture of albino and common fry. That may mean that particular parent fish was carrying at least one A gene (ccGGAa and CCggAA to make CcGgAa and CcGgAA)

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Investigation into the YY genes -- is it a form of leucism on a different fork to WW? What happens if you cross a Yellow to a Green Dragon, and what happens if you cross a Yellow to a Common (all common, carrying yellow) and then start breeding them back and forth to see if you can get Blue Eye Yellows that still have spots. Does the Y gene also depend on that disrupting effect of the GG gene? Logically, you would think we would have seen spotty yellows by now if Y did not also depend on G the way we think W may depend on Y. 

Investigation into Super Reds - are there really two types? Are the really clean ones actually Green Dragons underneath and they're cleaned up because of the gene disrupting the spots. 

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Once again, this is all purely hypothetical, but perhaps if we can crack this, it might open up the world of BN colour genetics up even more and we can start working out how to get even more colours. 

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Previous theory notes:

Version 2:

Version 1