A. cacatuoides genetics

[Ukilli]

Hello,

I have crossed male A. cacatuoides triple red (TR) to female orange flash (OF), and also did the opposite (male OF to female TR). TRs and OFs were from presumably pure lines. From the first cross got all fry (3 months old now) TR (some look more like double red (DR)), but from the second roughly half TR(DR) and half definitely OF. I expected to have same recombination picture in both crosses, or TR to be a dominant marker. Anybody can explain?

 

[fishgeek]

it probably is not just simple mendellian genetics as we all seem to feel most phenotypes are

by this i mean that the colour of the fish does not neccesarily have to be a result of just 2 colour(allele's) options
it may be multifactorial- more than 2 options combining to result in a colour(phenotype)
it may be co dominance is at play where neither triple red nor orange flash holds dominance over either and you can have a third phenotype(double red in this case) show from a combination of two different parents

hope that doesn't confuse things more
andrew

 

[cootwarm]

My original pair of OF cacs came from the same batch (siblings). The fins of the male were totally orange with no hint of red or spots. Now in his old age, he has a few spots on his bottom, rear fin.

Whenever this pair spawned, the male fry turned out to be about 25% OF, 25% TR, with 50% were a mix of "Double Red" and OF with spots of TR colors in patches on the orange. Most of the females had some splashes of TR color in their tail fin, but a few had an orangish tint to them.

Michael

 

[Ukilli]

Thank you for the explanations. It looks quite probable these traits (TR and OF) are controlled at least by two (or more) genes. It is also apparent that TR is not a strictly dominant (thanks Michael). Heterozygotes in "TR gene" probably are DR with extra color effect produced by OF alleles if present. Will see what happens in my "F2" if I have time for such scientific test.
Oleh