This is a theory that I just thought of, that would better explain Jack Dempsey genetics. Haven't really delve too deep into it or anything, but it would seem to answer a lot of questions in my mind, so here goes.
As most would know, Jack Dempseys come also comes in a popular color morph - electric blue, and less popular color morph - gold (more inclined to call it yellow, but hey).
Now, the general consensus is that both of the morph genes/alleles are recessive and the 'normal' coloration' being dominant, and so you can get gold or electric blue Jack Dempseys by breeding the recessive genes yada yada yada.
However, it irks me a bit - many recessive alleles are recessive because there are mutations that doesn't allow the gene product to function properly. In this case, the 'better' coloration (subjective, I know) would make seem as if it's a gene product that works, not one that doesn't. Think of the xanthic (pink) convict - it's pink because it lacks bars, and it's recessive. Albinism is where organisms lack melanin, and guess what... it's recessive. But yeah, it is possible for the recessive allele to be 'better' than the dominant allele, so I chalked it up as such.
However, it really still irked me and so I began to think of alternative possibilities.
Now, the genetics of the color morphs follow two streams of thoughts. One would indicate that the gold and electric blue alleles are both alleles of the same gene (So you have stuff like 'BB' (normal JD), 'bb' (EBJD), 'gg' (GJD), all variations of the same gene (and hence you can also have 'bg' and stuff). The second stream of thought is that they're separate alleles of different genes, so you have 'BB' and 'bb' for one set, and 'GG' and 'gg' for the other set, in which case for example your usuable 'EBJD' may be 'bbGG' or 'bbGg'.
However, it still irks me that these alleles are recessive. And then it struck me, that it could actually very well be the reverse - that an EBJD isn't electric blue because it has the recessive EB genes - rather, it may be caused from a lack of gold genes. In which case an EBJD, rather than being 'bbGG' or 'bbGg', would be 'BBgg' or 'Bbgg'. It felt like it makes more sense, so I searched for images of normal, gold and electric blue JDs via google images and compared them side by side - I noticed that an EBJD really looks like a normal JD that lacks the gold sheen, and vice versa.
Comparing these two pics for example:
http://www.liveaquaria.com/product/prod_display.cfm?c=830+889+2816&pcatid=2816
to
http://wereallwet.com/jack-dempsey-cichlid-fish-care/
The black background of the two is the same, the pearls are similar, just that one is very blue, the other one is not.
Delving deeper, I found this topic: http://www.gcca.net/forum/3-central...c-blue-x-gold-jack-dempsey-spawn?limitstart=0
It's a spawn between an EBJD and a GJD. If you go to page two, you'll see OP posting the offsprings after they've grown quite a bit, and they look like normal JDs. Which, if true, confirms my hypothesis.
In which case, the genetics of the two color morphs would be as so:
BBGG = Normal Jack Dempsey
BbGG, BBGg, BbGg = Normal-looking Jack Dempsey
bbGG, bbGg = Gold Jack Dempsey
BBgg, Bbgg = Electric Blue Jack Dempsey
bbgg = ???
The genetics of the fish in the above topic would then be bbGG (the Gold) x BBgg (the Electric Blue) = BbGg (all normal-looking) - which makes sense.
So yeah, basically my theory is that both electric blue and gold are dominant alleles. The recessive forms produces defective gene products that is either completely masked, or mostly masked (some EBJDs have a tiny little bit of gold on them and vice versa), which isn't surprising if the gene product, despite being mutated is still quite similar to the fully functioning form. And therefore, EBJDs are simply JDs lacking the gold, and GJDs are simply JDs lacking the electric blue.
In regards to the bbgg, I assume that they would lack both the gold and electric blue coloration (or only have 'em present in little quantities) - which may be what the black JDs are (like this: http://www.monsterfishkeepers.com/forums/attachment.php?attachmentid=339862&d=1237595538). Or it may not be that. *Shrugs*
But yeah. I think this would make more sense than our currently theories. May dig deeper later on for more evidence or something, this just popped into my mind, but it feels right.
----------------------
tldr;
Theory: Electric blue and gold are dominant alleles, EBJDs simply lack gold, GJD simply lacks EB, bbgg are black(?).
As most would know, Jack Dempseys come also comes in a popular color morph - electric blue, and less popular color morph - gold (more inclined to call it yellow, but hey).
Now, the general consensus is that both of the morph genes/alleles are recessive and the 'normal' coloration' being dominant, and so you can get gold or electric blue Jack Dempseys by breeding the recessive genes yada yada yada.
However, it irks me a bit - many recessive alleles are recessive because there are mutations that doesn't allow the gene product to function properly. In this case, the 'better' coloration (subjective, I know) would make seem as if it's a gene product that works, not one that doesn't. Think of the xanthic (pink) convict - it's pink because it lacks bars, and it's recessive. Albinism is where organisms lack melanin, and guess what... it's recessive. But yeah, it is possible for the recessive allele to be 'better' than the dominant allele, so I chalked it up as such.
However, it really still irked me and so I began to think of alternative possibilities.
Now, the genetics of the color morphs follow two streams of thoughts. One would indicate that the gold and electric blue alleles are both alleles of the same gene (So you have stuff like 'BB' (normal JD), 'bb' (EBJD), 'gg' (GJD), all variations of the same gene (and hence you can also have 'bg' and stuff). The second stream of thought is that they're separate alleles of different genes, so you have 'BB' and 'bb' for one set, and 'GG' and 'gg' for the other set, in which case for example your usuable 'EBJD' may be 'bbGG' or 'bbGg'.
However, it still irks me that these alleles are recessive. And then it struck me, that it could actually very well be the reverse - that an EBJD isn't electric blue because it has the recessive EB genes - rather, it may be caused from a lack of gold genes. In which case an EBJD, rather than being 'bbGG' or 'bbGg', would be 'BBgg' or 'Bbgg'. It felt like it makes more sense, so I searched for images of normal, gold and electric blue JDs via google images and compared them side by side - I noticed that an EBJD really looks like a normal JD that lacks the gold sheen, and vice versa.
Comparing these two pics for example:
http://www.liveaquaria.com/product/prod_display.cfm?c=830+889+2816&pcatid=2816
to
http://wereallwet.com/jack-dempsey-cichlid-fish-care/
The black background of the two is the same, the pearls are similar, just that one is very blue, the other one is not.
Delving deeper, I found this topic: http://www.gcca.net/forum/3-central...c-blue-x-gold-jack-dempsey-spawn?limitstart=0
It's a spawn between an EBJD and a GJD. If you go to page two, you'll see OP posting the offsprings after they've grown quite a bit, and they look like normal JDs. Which, if true, confirms my hypothesis.
In which case, the genetics of the two color morphs would be as so:
BBGG = Normal Jack Dempsey
BbGG, BBGg, BbGg = Normal-looking Jack Dempsey
bbGG, bbGg = Gold Jack Dempsey
BBgg, Bbgg = Electric Blue Jack Dempsey
bbgg = ???
The genetics of the fish in the above topic would then be bbGG (the Gold) x BBgg (the Electric Blue) = BbGg (all normal-looking) - which makes sense.
So yeah, basically my theory is that both electric blue and gold are dominant alleles. The recessive forms produces defective gene products that is either completely masked, or mostly masked (some EBJDs have a tiny little bit of gold on them and vice versa), which isn't surprising if the gene product, despite being mutated is still quite similar to the fully functioning form. And therefore, EBJDs are simply JDs lacking the gold, and GJDs are simply JDs lacking the electric blue.
In regards to the bbgg, I assume that they would lack both the gold and electric blue coloration (or only have 'em present in little quantities) - which may be what the black JDs are (like this: http://www.monsterfishkeepers.com/forums/attachment.php?attachmentid=339862&d=1237595538). Or it may not be that. *Shrugs*
But yeah.
I think this would make more sense than our currently theories. May dig deeper later on for more evidence or something, this just popped into my mind, but it feels right.----------------------
tldr;
Theory: Electric blue and gold are dominant alleles, EBJDs simply lack gold, GJD simply lacks EB, bbgg are black(?).
