Albinism ratio in P. pulcher fry

[Joe Gatchell]

So I have a pair that the female is albino and the male is a red morph (non albino). They have spawned twice and thrown 100% albino fry each time. 20 or so fry the first spawn and 30+ this time. What's the deal here? Why aren't they throwing some non-albino fry?

 

[viejo]

Interesting. It would be good to see some pics of the parents. If I am reading this right, the male is dark (wild coloration) with a red belly & chin & the female is normal albino, is that correct? Actually, if I'm recalling correctly, in pulcher both pure albino & heterozygous exhibit pink coloration. If my recollection is correct, a pure albino crossed with a normal colored mate would either throw 100% het fry or 50/50 albino or het fry which all would show pink coloration. I did a little research, check out this thread: http://www.apistogramma.com/forum/index.php?threads/are-they-true-albinos.10958/

 

[Joe Gatchell]

In P. pulcher albinism is a dominant trait. The strains that throw both albino and wild type are heterozygotes... one of each gene type. Heterozygous albinos tend to be more hardy, and are therefore the most common. Homozygous albinos, even if only one of the pair is truly homozygous, will through 100% albino.

Could it be she's homozygous albino then?

Female is a little blurred but you get the idea.

 

[wethumbs]

Just do the punnett squares.

 

[Joe Gatchell]

Just do the punnett squares.

I'm a truck driver not a biology student. Have no clue how to do those.

 

[gerald]

Yes ... 100% albino offspring ... how much more proof do you need? Looks like Ted must be correct on the albino gene being dominant in P.pulcher.
IF albinism is controlled by just one gene (maybe it's not that simple), then dad should be homozygous normal, all their kids should be heterozygous normal/albino, and a pairing of those kids should yield 75% albino and 25% normal.

Could it be she's homozygous albino then?

 

[Joe Gatchell]

This is all above my pay grade. Just wondered how a non albino and albino were throwing 100% albino fry. Guess I got my answer. Thanks.

 

[wethumbs]

Sorry Joe, what's obvious to me may not be so clear to others.
It is really very simple. I have attached the punnett squares for F0 and F1.

'AA' is the female albino (dominant gene), 'aa' is the red. Crossing the two will get you 100% 'Aa'. Since 'A' dominants 'a', all the progenies will exhibit albino trait. However, they are all heterozygous albino as they all carry the 'a' gene but do not exhibit its physical characteristic (in this case, the red morph).

Breeding the first generation together (Aa x Aa) will get you 75% albino (AA, Aa) and 25% red (aa).

If the albino female you have is a heterozygous to begin with (Aa) instead of a homozygous (AA), then you will not get 100% albino offspring. Therefore, your female albino is a homozygous. A heterozygous albino female crossing with a red (aa) will get you 50% heterozygous albino and 50% homozygous red as indicated by the following Punnett square.

 

[Joe Gatchell]

Sorry Joe, what's obvious to me may not be so clear to others.
It is really very simple. I have attached the punnett squares for F0 and F1.

'AA' is the female albino (dominant gene), 'aa' is the red. Crossing the two will get you 100% 'Aa'. Since 'A' dominants 'a', all the progenies will exhibit albino trait. However, they are all heterozygous albino as they all carry the 'a' gene but do not exhibit its physical characteristic (in this case, the red morph).

Breeding the first generation together (Aa x Aa) will get you 75% albino (AA, Aa) and 25% red (aa).

If the albino female you have is a heterozygous to begin with (Aa) instead of a homozygous (AA), then you will not get 100% albino offspring. Therefore, your female albino is a homozygous. A heterozygous albino female crossing with a red (aa) will get you 50% heterozygous albino and 50% homozygous red as indicated by the following Punnett square.

Thanks, that makes sense.