Cobalt progeny contain blue diamonds?

[mawhins]

Hi all,
I have a breeding pair of cobalts. Have just gotten the first batch of fry to 50c piece size. 25% of them are completely devoid of stress bars and only these fish are showing blue sheen over a light base. I know they have a long way to go but from what I've read cobalts have stress bars and blue diamonds don't.

I don't have any information on the genetic makeup of these parents but I guess its reasonable for them to carrying bd genes?

Time will tell but I'm impatient and would love to know more about what to expect if any of you know about the history of cobalts and or basic genetics. Uni was far too long ago.

I'll try to get some photos up tonight.
Here's a video of them, couldn't get a decent photo.
http://www.youtube.com/watch?v=5jHfHqQRFnM

[ILLUSN]

BD was derived from cobalt, cobalt was the 1st "solid blue discus", concider Bd and ocean greens improvements on the cobalt.

[mawhins]

Ahh i see. So the Cobalts I have must be heterozygous for what ever gene expresses as vertical bars.

[ILLUSN]

kind of, they've been bred over years to express lighter stress bars, even BD's usually have a bar just at the base of the tail.

all discus are pretty much the same species just diffrent colour varients, just like people

[sunshinediscus]

Blue diamond is controlled by a recessive mutant gene, so your results are to be expected in the case where both parents are carriers. This is a true mutation and was NOT developed by gradual steps from Cobalt discis. The blue diamond is a case of FINDING, not simple selection as many think. Genetically, they are very different breeds.
It is not uncommon for breeders to cross with blue diamonds, then by using the laws of inheritence, one can add the bd mutant gene to other types. This has been done with the pigeon gene, golden gene, albino gene and others.

[ILLUSN]

WELL SAID!

[mawhins]

So for argument's sake. Let's say the 10 lighter fish in the brood were the result of the bd mutant gene. If I line breed a pairing of these siblings would the offspring end up homozygous for the gene? Something tells me its not going to be that simple.

[sunshinediscus]

So for argument's sake. Let's say the 10 lighter fish in the brood were the result of the bd mutant gene. If I line breed a pairing of these siblings would the offspring end up homozygous for the gene?

Yes :)



Something tells me its not going to be that simple.

why not? When we are dealing with a single gene mutation like the bd, it really is that simple. Controlling quantitative genetic traits is the difficult bit for linebreeding a nice strain, that is controlling features like shape, fins, iridescence of color etc etc.

[mawhins]

hmmm interesting. We shall see what we shall see I suppose. I was thinking i should try and outcross the standard cobalt looking fry to some other blue strain to build more blue, the parents are not fully blue. Then again is it worth the time and effort doing that if i'm not aiming for something special and/or different. I should probably just buy a better quality breeding pair.

[scoob]

I bred two Brillant Turks lately and out of a spawn of 70 I had about 6 Blue Diamonds solid colour, with line bred discus you can never say what you would end up with.

[sunshinediscus]

hmmm interesting. We shall see what we shall see I suppose. I was thinking i should try and outcross the standard cobalt looking fry to some other blue strain to build more blue, the parents are not fully blue. Then again is it worth the time and effort doing that if i'm not aiming for something special and/or different. I should probably just buy a better quality breeding pair.

Yes, i would see what comes from it first. You never know, sometimes ordinary parents can produce great looking fry. Your line sounds like it came from a crossing at one point which in itself is not bad i don't think. But it does mean a major recombination of genetic traits which leads to a lot of variation between individuals. The type will go backwards in quality without strict selection and a certain measure of luck.

[sunshinediscus]

I bred two Brillant Turks lately and out of a spawn of 70 I had about 6 Blue Diamonds solid colour, with line bred discus you can never say what you would end up with.

Perhaps with uncontrolled linebreeding, you never know what you would end up with. But i think the point of line breeding, is to iron out those uncontrolled bits and purify the type to the point where they are homogenous both in phenotype and genotype. This ideal is not possible with some 'strains' due to other complications, but i think it should be the ideal.

[ILLUSN]

As I said before most discus are effectively 1 species just different color variants even with line breeding you will get genetic rearrangement of genes. Some will be turned on others off. Line breeding will increase the chances of your desired gene being selected and expressed but nothing is guaranteed. Remember pigeons were genetic mutants from Turks which were selected ( line bred) from wild blues and browns.

[mawhins]

Has anyone tried to map the "family tree"? At a high level I mean. Illusn you seem to have a good understanding of what came before what and which variants were crossed to make the colour forms we now see. Many years of experience and reading I'm sure.