Mouse Coat Colour

More than you ever wanted to know...

Okay, here is why I did this: I have a genetics class that you need to have a project for. I thought, hmmmm... I own mice, I own a snake, why not do an exsperiment in mouse coat colour and use the exstra mice for snake food? Cold hearted? Maybe. Interesting? Certainly. So here we are 4 months later with a tale (tail?) to tell! Enjoy.

These are the Parental types the black mouse is the father and the white one is the mother. The mother is actualy Albino which is a mutation (Aabb or aabb). The Aabb is how we show genotypes, the rescessive trait is in lower case and each letter reprsents a diffrent gene. There are 50 genes that control mouse coat colour!

The father is officaly Nonagouti (aaBb or aaBB), which is a hetrozygous recessive trait, in other words he has black fur. The dominate trait is Agouti (AaBa or AABB), which gives the mouse a brown coat. The intresting thing is that since these are found on diffrent locus (place on a gene) when you mix the albino and the black you get brown! See? Aabb x aaBb = AaBb

These two pictures are the offspring of the above parents. As you can see they are all brown.

They grow up so fast! And soon they were ready to be mated back into each other. These are two of the adults from the first set of offspring. Now it may seem like incest to the rest of us, but in animals this is quite common. By inbreeding two siblings you increase the chance of recessive traits showing up. Which brings us to...

Just look at this gentic mess! There are a total of five diffrent coat colours here! There are seven of the dominate Agouti (brown), two Nonagouti (black), three Albino, and the real surprize: two Lethal Yellow, and two Silver!!

The Lethal Yellow is called 'lethal' because if the egg and sperm that come together both have the Yellow gene then the union will never turn into a mouse. That means that we know for a fact that the yellow ones are heterozygous for this trait.

Here is a cute picture of the five diffrent varities of mice that we got. Rest assured that the Silver and Yellow mice have been given homes as pets. Now I know that it isn't fair that the others will most likely become snake food, but that's the way of the world! Only the strong or the beatiful survive!

See what I mean. This is my snake, Aliwishes.

But wait! There is more! I also crossed on of the sons back into the Albino mother. (In fact all in all I had about 38 mice involved in this exsperiment! Three of them escaped into my house!). These ones came out fity/fifty for Albino and Agouti. This is exspected since there these ones were not exsactly inbreed therefore they didn't get the rescessive traits showing up.

So the next time you see a common house mouse think again about how complex even the simplest of creatures is!

If you have any other questions e-mail me at