Hatching BBS Wiki Article
After going through a bout of bad BBS hatches, I finally put my finger on the problem, and now am enjoying better hatches then ever. Read about the methods I use to hatch brine shrimp eggs in this Wiki article:
No Such Thing as a Bad Cross
A recent discussion on the Guppy Designer forum brought to light an enduring truth for the guppy genetics hobbyist.
The best crosses are not those that work out according to plan. The best crosses are those that produce unexpected results.
From a geneticist point of view, a successful cross confirms something that is already known. That is useful for validating information. But an unsuccessful cross leads to questions that have no answers. And that is where learning and new knowledge starts.
You spent two years following a hunch about the interaction of certain genes. But all your attempts at confirming the hunch failed. If you did not record in pictures and words the results of the failed crosses then you indeed wasted your time. You wasted a very, very valuable learning experience. What do you have to show for it? You have harvested the negative when there was so much positive to harvest.
Let's look at an example of this. The discussion on the GD forum was about how to improve the green color of an American solid green guppy.
This "Florida Green" looks more blue then green. How would you make it "greener?" Good question.
Intuitively you would think that crossing a yellow guppy with a blue guppy would yield a green guppy. That's because guppy green is composed of two color cells, blue light reflecting iridophores overlaid with a semi-transparent yellow pigment layer of cells. It is a simple color mixing model: yellow plus blue equals green. But this cross does not work. Apparently when you cross an American half-black yellow with an American half-black blue, you get a gray color. (As an aside, I would say this is very strong evidence that tables that try to simplify guppy genetics into simple color blending are useless to the practical breeder.) The expert breeders suggest the best way to alter the quality of green on a solid or half-black green guppy is to cross it with a solid blue or half-black blue guppy.
Half Black Yellow. You don't actually see much yellow in the body.
I find the failed crossing much more interesting than the successful crossing. In fact this is a cross I want to try in the future precisely because it does not work. I'll bet in doing a reciprocal cross and following it through two generations to the F2 I will learn a lot about guppy yellow and blue.
My friend Bill Gill and I were discussing this and he pointed out that the fins on the half-black yellow actually have a lot of white in them. In fact it is the case that the half-black yellow has entirely different genetics for the body and the fins, as the body does not have leucophore color.
That observation by Bill turned on light on my head. Of course! This combination of white leucophores (a type of cell composed of white pigment) and yellow color cells is found in the Full Platinum from Asia. What is interesting is that Full Platinum is actually a half-black yellow as well, the difference being that the yellow / white color is on the body as well as the fins. The so-called "yellow platinum" color of the Full Platinum covers up the half-black area of the body.
Full Platinum (Full Gold Leucophore) Notice the dark yellow color of the peduncle. Full Platinum genetics converts black to yellow.
I have written a chapter about the genetics of the Full Platinum in my latest "Design Lab" book. In it I show that the Metallic Gold (Mg) gene is responsible for the yellow color.
The yellow in an American green is a different yellow. It exists apart from leucophores. That is the reason why the cross does not work. The yellow on the half-black yellow is a completely different gene. And the reason you get gray when you do the cross is because you are introducing leucophores into the mix.
Why is the blue a good cross to greens? I suspect there are blue and yellow modifier genes that up regulate or down regulate the pigments involved, the color cells or both. Think of these modifiers as acting like digital thermostats turning the colors up or down. Only a properly documented cross will begin to confirm or deny this theory.
I have always found that the learning occurs during the process of documenting the cross. You cannot properly evaluate a cross with your naked eyes looking into a tank. You need to take a picture and put it on the computer screen and really look at it close up. You need time to think about it. The second generation of a cross is where segregation occurs. The genes break out and recombine in different ways, showing you in glorious colorful detail how the individual genes are interacting. In the act of sorting through the pictures and discovering the different gene combinations learning occurs. In the act of sitting down and writing about what you see, you organize your thoughts, follow along a line of reasoning. compare pictures and ideas to other research, think objectively and critically. The temptation to see what you want to see is too great otherwise. And often the key to a mystery is found in a small detail that your naked eye would have missed or you would have missed because you did not think about it in a logical and thorough manner.
My discussion raises the possibility of another cross: between the half-black yellow and the Full Platinum. This would be a good cross for altering the body shape and intensity of yellow on an Full Platinum, or vice versa, improving the yellow and body shape of a half-black yellow. Would this be a good cross? The problem it would pose for the person attempting to "improve" the half-black yellow is that the genes for the fins and the body on the Full Platinum are probably linked on the same chromosome. You would have to do quite a few crosses before they would separate out. This linkage may exist going the other way as well. But it might be worth it in the long run.
I really like discussing bad crosses. Look what happened in this discussion. We discovered that the difference between the Full Platinum (which I tend to call the Full Gold Leucophore) and the American half-black yellow is the presence of the yellow / leucophore genes in both the body and the tail of the Full Platinum. Can't wait to test this theory with a cross between these two strains.