Guppy Genetics

[Cinnebuns]

I'm trying to do my own research on this and my head is spinning. I understand basic genetics but can't find the answer to what specifically I'm looking for. I would like to know what type of traits fin size and color are so I can more wisely pick which I want to breed together. Recessive/dominant or X/Y?  I heard somewhere that color is inherited from the male. Does this make color a Y trait? How does tail size fit in?  Those are the only 2 traits I'm really worried about for now. Health ofc is always a factor. 

Edit:  additional question:  one thing I did understand from some of the charts I read is that I never saw purple listed. Is purple a genetic anomaly or something? It reminds me of something someone on Facebook once said to me about purple guppies not being natural. Is this a color I should not try for?

Edited January 8, 2022 by Cinnebuns

[Fish Folk]

I’m not an expert. Just a low-brow understanding. I’m glad to be corrected!

The way I think about this is that there are a variety of different traits. Let’s number them something like this…

1. Fin size

2. Fin color

3. Body color

Now, to simplify… for each trait, let there be a Dominant X and a Recessive Y. This  would theoretically break down according to the genetic makeup of male and female into three different Punnett squares, one for each trait.

So, for example:

A large-finned male is crossed with a small-finned female. Let’s say small fins are a dominant trait. Now, the question you may not be able to answer is this: Is the small-finned female an XX or an XY? Both would appear small-finned, but one is heterozygous (XY) meaning that large-finned trait will distribute more readily to fry. Let’s say she’s XY. The male is YY. So.. fry end up distributing this trait like this…

50% = XY

50% = YY

Half will look small-finned (dominant heterozygous), half will look long-finned (recessive).

But now let’s add in another trait: fin color. Let’s say that Red is dominant and Blue is recessive. And let’s say that the large-finned male above is Red-colored, while the short-finned female is Blue. And, for argument’s sake, let’s say he is XX for the red trait, while she is YY.

So, the result will be…

100% = XY

So ALL fry will appear RED in color, but ALL will be heterozygous, meaning that their fry would split back out to Blue and Red again, but only 25% of the 2nd generation would be blue.

But let’s think about this now. If all you really want to selectively breed are large-finned, pure Red Guppies … you’ve got 75%, but none of them will breed true.

Add red body vs. silver body as a third trait consideration, and even more issues arise. It is very hard to line breed a fish exactly as you want it, because the challenges of each trait are multiplied by the reality that there are many more than “x” and “y” two-choice binaries. There are dozens of colors. Only very experienced breeders know what is dominant and what is not. 

Edited January 9, 2022 by Fish Folk

[GameCzar]

I'm following this thread because this interests me too.  
I did find this PDF that helped me understand the basics.
https://www.myaquariumclub.com/images/fbfiles/files/GuppyGeneticsPrimer.pdf

[Fish Folk]

Some miscellaneous guppy stuff…

We did this for a 5th grade class a couple years back…

And here is a Firecracker Guppy line my son earned BAP for…

Here is what I’m working on now indoor with my “mutt guppy” breeding project…

 

[Fish Folk]

The way that I think about breeding guppies is to take one of several approaches:

(1) Buy a bunch, and breed them in ponds / tubs, and collect them after a season (preferably with some sunshine). Now, you can then select certain “breeders” and line breed them.

(2) Buy select. Get highly rated pairs, and focus on an exclusive line, culling to preserve the best. Since this eventually inbreeds, in theory do this with two lines, and cross these to prevent detrimental genetic weakness. Or, buy a new fish to breed in and “reset” the genes.

(3) Breed up a mixed batch, and separate out only the most desirable to continue community breeding. Similar to #1, but not ending in “line breeding.”

(4) Breed up a mixed batch, but only remove “undesirables.” Maintains broad diversity but roots out the worst. 

[PineSong]

On 1/8/2022 at 5:23 PM, Cinnebuns said:

Is purple a genetic anomaly or something? It reminds me of something someone on Facebook once said to me about purple guppies not being natural. Is this a color I should not try for?

I'm no expert and the videos and articles I've seen about guppy genetics made my head spin, too. I have seen purple guppies listed on Aquabid and in some videos but I get the feeling it's a very unstable color, genetically, or we would see it more often. Here is a video D.Grey had about his:

and Hawaii Hobbyist has some in this one:

 

[Levi_Aquatics]

I have a strain of purple mosaic guppies and they look great from the top but not so amazing from the side so i put them in a low aquarium so I can look down at them. They throw a few Rainbow colored fish that I have to cull but I still love them!

[Cinnebuns]

So it sounds like purple isn't a good choice to start with since it's more difficult. I'm thinking then of going with blue since it's similar. Am I correct that blue is the recessive of red?  So I wanna avoid any reds that come out?

[GameCzar]

On 1/9/2022 at 11:40 PM, PineSong said:

I'm no expert and the videos and articles I've seen about guppy genetics made my head spin, too. I have seen purple guppies listed on Aquabid and in some videos but I get the feeling it's a very unstable color, genetically, or we would see it more often. Here is a video D.Grey had about his:

and Hawaii Hobbyist has some in this one:

 

D Grey has great vids about breeding!