This article is from the WSSF 2010 AFRMA Rat & Mouse Tales news-magazine.

Candy Evans, NRMCI, New Jersey, e-mail
Q I have some questions regarding the Transgenic (Splashed) mice. Well, actually, can you tell me a little more about them. I’ve been told that you have to breed them to Siamese or to each other. Here is what I’ve been told regarding the transgenics.

Originally, Mike Chiodo got them from a lab supplier. He gave one single male to Beth Cooper with instructions on how to make more—breed it to a regular Siamese. We later got some others from him, but always the same process. Beth undoubtedly gave them to Wanda Wilson, and either Wanda didn’t trust what Beth told her, or Beth didn’t tell her how to make more.

The transgenic is not quite as simple as a plain dominant—it’s actually a scientifically altered gene on the C locus which suppresses the dominant C except in spots, allowing a recessive to show up as the background color. It only works on the C locus, which is why they are generally Siamese splashed with Black. You might be able to make Coffee splashed with black. You might be able to make them splashed with chocolate. If you outcrossed, to say, the reds, you might get white splashed with red. If you bred in albino, you’d have white with spots—both would look just like regular spotted mice, so not such a great idea. If you went to the silver/champagne dilutes, you’d probably get white splashed with silver/champagne—again, looking like a regular spotted mouse. So you really only want to breed them to Siamese or to each other.

Is this correct? What other information can you give me.

A Good to know this information. What Wanda told me is one of their people got them from a Lab (I don’t remember who) and they were created from gene splicing and to never outcross them or you will lose the pattern. The original ones I got from Wanda Wilson in March of 1995 always threw Transgenic and PEW in every litter—nothing more. The TG were everything from super dark, almost a self Black, to less black splashes and more background showing through. All the outcrossing I’ve done to make other color versions are not spotted mice whatsoever—they are the splashes on the background color.

Two of the original transgenic (Splashed) mice I got from Wanda Wilson in March 1995. Note the ruby eyes on the lighter one. These were black mice on a gray background, nothing Siamese there.

Some Black Splashed mice from my first litter in August 1995 from the original stock from Wanda Wilson, owned and bred by Karen Robbins.

I don’t recommend breeding them to Siamese. They come out a muddy mess—instead of the gray background you get “mud” plus points. You can see the Siamese points and shading but they have the splashes on top of it, and because of the brown background of the normal Siamese, the background on the Splashed are a muddy color. I’ve had light marked Siamese Splashed, and I’ve also had very dark ones that really look like mud. I’ve also seen one that looked like a Siamese Sable Splashed.

A Siamese Splashed from 2000, owned and bred by Karen Robbins.

A Chocolate Fox Splashed from 2000, owned and bred by Karen Robbins.

I’ve also had them in Fox/Tan. Interesting when you get the Tan gene in there. The belly for the most part will be a Fox/white color except where a very dark splash mark would be and those are Tan/orange.

An odd-eye Black Splashed male from 2007 showing very nice type and size, owned and bred by Karen Robbins.

A Splashed 4-week-old kitten from 2001 showing patched markings in black, “brown,” and light gray which would work well to make “tri-color” (Broken-Multi) mice, owned and bred by Karen Robbins.

When I outcrossed them in 1998 to one of my English Beige Fox males so I wouldn’t lose them, that’s when I found they are dominant, so you don’t have to breed to each other to get more; however, once you get some, then breed them to each other and have separate lines going with them. You will get mostly PEWs with a few Splashed if you breed them to a PEW. When you need to outcross to improve something, then I put them into English (take a Splashed female to an English male) then take those and breed back into the Splashed. Since they are dominant, it is very easy to improve the type and size on them by outcrossing with the large English show mice. I’ve found I can breed Selfs out of Splashed to a non-Splashed and still get Splashed (only a couple but still there). They will throw Selfs in every litter—mostly PEW. I will keep PEW females once in a while (or another Self color) only if they show exceptional type, to use them to breed back with a Splashed. I normally don’t keep Self males out of Splashed (though I did keep one really nice PEW male with good size and type and bred him to Splashed and got very nice kids; you just don’t know what the splashing is like on the Self colors)—I always use Splashed males with Splashed females or Self females. Any Selfs that you keep out of Splashed, make sure you keep a note that they are out of Splashed so you won’t breed them into your non-Splashed lines or you may have Splashed showing up when you aren’t expecting it.

A Blue Splashed (L) and a Lilac Splashed (R) from 2003, owned and bred by Karen Robbins.

A Champagne or Beige Splashed 4-week-old kitten from 2000, owned and bred by Karen Robbins. You can barely make out the splashes.

A light Chocolate Splashed on white from 2000, owned and bred by Karen Robbins.

A Dove Splashed, SPS Splashed, and Dove Fox Splashed 5-week-old females from 2000, owned and bred by Karen Robbins.

A 5-week-old Lilac Tan Splashed female from 2000, owned and bred by Karen Robbins.

A 14-day-old litter of Lilac Splashed on white kittens (one is Satin) from 2007, owned and bred by Karen Robbins.

A 6-week-old Lilac with Lilac Splashes kitten from 2010, owned and bred by Karen Robbins. The dark “spots” are the splashes. They usually become almost impossible to make out once they grow up.

The most dominant color is the Black (classic) splashed. I’ve also had Chocolate (pretty), Blue (pretty), Beige on white background (too light), Champagne on white (too light), Dove (okay), Siamese (yuck), and Lilac (a lot I have are on a white background with Lilac markings but I’ve also had Lilac Splashed on a Lilac background as well which are hard to see the splashes). The background seems to be affected by the color it was bred from. For example, I use a lot of PEW Selfs so some come out with a white background. I’ve had a couple Black Splashed with a very light/white background, but I didn’t keep those going as the Standard calls for a gray background. You will notice several different colors in the splashing—black marks, gray marks, brownish marks all on one mouse. Ideally, you want small splash-spots all over—not specific markings/patches. Also, odd-eye is a common thing—not real obvious with pink/black eyes, but with black/ruby eyes. Also, ruby eyes are common—very odd to see a “black” mouse with ruby eyes but they have it.

So, that is what I can tell you based on my experience.

I then asked Mike Chiodo for information on his experience with them and who got them from the lab; see e-mail below and the article “Transgenic Mice & Tricolors.” Karen Robbins

Mike Chiodo, NY, e-mail
Re: TRIs: On 1-28-96, I received 5 splashed mice from Wanda Wilson. She told me they had come from a lab, and I can’t remember who it was that got them (a mouse person who was also a lab technician, I believe). She wanted me to try my hand at breeding them, because she was about to lose them and wasn’t having much luck. These mice were not very healthy, and two of them died soon after I acquired them. The others developed bulbous joints as they aged, almost like arthritis. I immediately crossed these remaining mice with my own mice and in a generation had improved the line immensely. I continued to breed these splasheds, and eventually got more and more color combinations. On 4-15-96 I may have gotten my first poor tri, but she was tiger brindled and caracul with a little bit of pied possibly so it was hard to tell what was going on. On 12-7-96, after a few generations, I got my first true tris, two bucks—Figarucci and Varmint. They were caracul and had patches of black, beige, and white fur. They were still not the best tris, but after that I bred tris to look much better, and tried to distribute them to others, including giving a bunch back to Wanda, who then gave them out to other breeders as well. By the way, I didn’t meet Pedro (Guppy) till much later (maybe 4 or so years later?), after they had been well established in the community, but he took a liking to tris and was someone who definitely helped get them out to the masses in the 2000s.

A somatic mosaic mouse from 1980 owned by Linda Huscher. This mouse has Black, Beige, and white patches.

Question to Carmen Jane Booth, D.V.M., Ph.D.
Q Have you ever heard about or seen a “tri-color/calico” mouse in the lab stock? We get somatic mosaics on occasion in both the rats and mice, and England had the varitint waddlers many years ago, but was wondering if there is a true “tri-color/calico” out there. Karen Robbins

A This is a complicated question. First of all the gene for hair color is on the X chromosome in cats.

Tri color or Calico cats are usually female because the triple hair color is due to trisomy X, that is the cat has three X chromosomes where XX/X in some cells because there was failure of meiosis and one X chromosome did not divide. Note the scientifically correct way of indicating this genotype for this type of individual is XXX/XX. Second you have X-inactivation because in any one cell (skin cell for example) the cell has to choose which coat color gene to express and inactivates the other gene. Thus, in a cat with an X/XX phenotype the cell has three choices and you can get the three different coat colors. This is not a problem in female cats but in male cats an XXY/XY genotype results in the disease syndrome known as Klinefelter’s syndrome. Male Klinefelter cats have problems with infertility and respiratory problems. Cat coat color and pattern genetics is complicated. Here is a good link http://en.wikipedia.org/wiki/Cat_coat_genetics.

Coat color in mice is different. There are experimental mice with Klinefelters, but there is no mention of coat color. Here in research we use predominantly inbred strains for uniformity and most are either black, agouti, or white (albino). I have never seen a tricolor mouse. Here is a nice paper on mouse coat color genetics www.afrma.org/pdf/mousecolorgenetics.pdf.

Go to Transgenic Mice & Tricolors