Genes: You are Richer Than You Think

I have been so busy on my books this summer that I have been neglecting the documentation of my crosses, like the above beauty that came out of an experimental cross between a Kaden Snakeskin male and a Silverado (Magenta) female. I wanted to see the effect of the magenta gene on the snakeskin pattern. I got a wide variety of phenotypes, including a version with a solid blue body and red spotted fins. and the above Peacock version with its expression of the snakeskin pattern in the belly and fins. In fact, what really surprised me about this phenotype is that it has the same pattern of expressions as the Schimmelpfennig Platinum sword X Kaden snakeskin cross I did some time ago. I called the result of the cross a "Medusa."

You can see why I call this phenotype a "Peacock" can't you?

I have created a graphic for a new book I am writing that attempts to divide the guppy body into the zones you see in crosses like these.

The graphic is based on a photo of the Medusa. As you can see the Peacock's pattern of expression fits these zones.

The new book I am writing surveys the scientific literature of guppy genetics and color biology, and wanders into related fields and even goes as far afield as the work of Sean B. Carroll, the Evo-Devo proselytizer. I have found his book "Endless Forms Most Beautiful" to be a treasure trove of information on the biological and genetic basis for patterns, from zebrafish to zebras.

You do not normally think of guppy bodies as being segmented, but it is, and it is well established that color cells migrate to positions on the body probably using a world coordinate system (longitude and latitude plus height and depth) as well as local cues like the segmentation of the body. Reading Carroll's account of how hox genes pattern the body leads me to believe that the half-black pattern is coincident with a major division of the body. I develop a case for this in the new book.

Actually Carroll's book is not that far afield from guppy studies as you might think. Carroll is presenting fundamental research into how vertebrate bodies are patterned. The patterns on animals like butterflies, zebras and zebrafish are the expression of the same basic processes that create arms or fins, hair or scales. So the key to reading Carroll is to relate his fundamental principles of pattern formation back to guppies. That is exactly what I am doing in the new book. Of course this is only one chapter in the book. In another chapter I survey the work of Fujii and Bagnara, whose study of pigmentation systems is key to understanding guppy color and pattern. And I plan to do a chapter on the current research being done on zebrafish patterns.

In the past couple of months I have also been working diligently on a project that I set for myself a couple of years ago, which was to collect and incorporate into crosses all the known mutant genes of the guppy. The snakeskin X magenta and snakeskin X platinum crosses are part of that program. I have a grid on the wall in my fish room that lists all the genes I have collected and the combinations I have done, or are in the process of doing. I am documenting those crosses and using the results to update my existing books and as fodder for new books. For example, I have discovered that the Micariff guppy is not the result of a simple cross of a snakeskin and a Stoerzbach guppy. So the prevailing wisdom about the genotype of a Micariff is probably wrong. I will probably have to go the other way and take apart a Micariff to see what genes it really does have. I have tentatively called it the "solid" gene, using the name given to it by some Asian sources.

One of the crosses I have done is a reciprocal cross between a Moscow and Full Red. I wrote about this in a previous blog. The update is that I succeeded in creating a Full Red Moscow in the very first generation. All you need to do is use a heterozygous or homozygous blond Moscow and a blond x-linked Full Red. At first I was incredulous. But fortunately Rick Squire (the retired genetics professor) was riding shotgun on this foray into the unknown. He helped me analyze my results and came up with many astute theories for the anomalies I found. This is going to be a chapter in one of the books I have planned. Here is a picture of a Red Moscow male taken at four months of age.

You see a lot of blue and purple metallic in the body...but this is typical of a Full Red at this age. Here it is five weeks since that picture was taken, and the male in the picture is just as red as his Full Red cousins at the same age. And the Red Moscows have something their cousins do not have: there is red color developing on their heads. The other trait that betrays their Moscow heritage is the spotting you see in the caudal fin. It will be interesting to see how they turn out in a couple of more months. Meanwhile I have them set up with Full Red females. I already have a drop from siblings. It will be interesting to see how they color up, as they have the Midnight black gene...

I titled this blog, "Genes: You are Richer Than You Think." The phrase is actually an echo of a advertising slogan used by a Canadian bank. What it means in the context of guppy breeding is that you can create new guppy strains from the genes you already have in your fish room, like the Peacock from snakeskin and magenta strains, or the Red Moscow from Moscow and Full Red strains. But there is another meaning. I have been missing an important gene in my grid of crosses. That is the golden gene, which is called Bronze by Americans, Tiger by Asians, and Gold by Europeans. But last week a Midnight Black Moscow female dropped what I first took to be a blond fry. Then it developed some black color. I was puzzled until Rick pointed out that it may in fact be a Golden. I think that must be it. So I have had the golden gene all along, hidden in my Midnights. In terms of guppy color genes, I am richer than I think.