Chocolate???

[fishes2catch]

Hi All,

As I have stated before, I'm a newbie to goldfish so please be gentle.

What does it mean to be a chocolate goldfish both at the tissue and genetic level?

Mark

[joe]

It simply is a a darker brown colored goldfish, usually seen in orandas mostly and now showing up in ranchus. They are very attractive though not as popular color as some of the others. I am not sure what you mean at the genetic level

[fishes2catch]

What I was wondering is if it known if this is an increase/decrease in the amount of melanin? xanthine? guanine? and at what tissue level. Also, has anyone worked out the genetics of the brown trait?

Mark

[Virginia ranchu]

Mark,

I have the Joe Smartt book on goldfish genetics, and I will see what he says about chocolate and let you know if there is any information there.

Keep in mind that many goldfish color varieties are transient. Also, goldfish are tetraploid (4 copies of each chromosome), so there are significantly more genotype possibilities than with a diploid species. I had a chocolate colored Ryukin which eventually became all red at about 15 months old. I think these fish have fewer copies of the demelanizing gene, or perhaps a different mutation all together which causes a much more gradual loss of melanin.

Just my guess.

Rob

[bekko]

The Chen paper which Guenther pointed us to a few days ago has the best information on the genetics and pigmentation of blue and brown coloration. I believe the reference is in the veiltail breeding thread.

-steve