Predicting the Future

Predicting the Future

Okay, so you have some mice, you want to breed them, and you have some particular goals in mind. Let’s go back to our friends Hershey the chocolate doe (girl) and Ashes the lilac buck (boy). What might their babies look like? Anybody interested in statistics and probability?

Let’s look at Hershey and Ashes genetically first.

Hershey is a chocolate, so we can look at the chart and know she looks like this: aabbC*D*P*. Simply put, Hershey is a self with the brown dilution and black eyes.

Ashes is a lilac, so he looks like: aabbC?ddP*, he’s a self with both the brown and the blue dilution, and black eyes.

So, let’s look at the recessives first. Both Ashes and Hershey have brown bb, which means neither one has the dominant “not brown”. All the babies are going to get a “b” from Hershey and another “b” from Ashes, so they’ll all be bb, which is brown.

The babies will all get blue d from Ashes, and they’ll get either not-blue D from Hershey, or they’ll get the mysterious “*” for the gene we don’t know, which could be either D or d. If you think about probabilities, half the babies will get the D from Hershey, and the other half will get the *. So half the babies will definitely be Dd and not blue, but the other half could either also be Dd and not blue, or they could turn out dd and blue if Hershey is hiding a recessive blue gene!

How do we know what recessive Hershey might have? Well, you can wait for the babies, and if you get blue ones you know she had it. If you know what Hershey’s parents looked like it can help you guess, too. If one of Hershey’s parents was blue, she definitely has the gene, just like all Ashes’ babies will have blue and brown recessives from him no matter what their mother looks like. Otherwise, you just guess, usually.

If both Hershey and Ashes are hiding a recessive “p” so that they’re Pp, then some of the babies could have pink eyes, but otherwise they’ll all be P* with black eyes.

They’re both “selfs” so the babies will also be “selfs” because “a” is a recessive. And they both are “bb” brown, so all the babies will be colors with brown.
So, the babies will have:

  • aabbC*DdP*, chocolates just like Hershey, is a guarantee.
  • aabbC*ddP*, lilacs like Ashes is possible if Hershey carries blue
  • aabbC*Ddpp, Champagnes, if both parents carry pink eyes
  • aabbC*ddpp, Lavenders, if both parents carry pink eyes and Hershey carries blue.

See, you know what the babies will look like and Hershey hasn’t even met Ashes yet!
Okay, it isn’t quite that simple, because we haven’t played with the C-Locus here. If both Ashes and Hershey are recessive for albino, you’ll get some surprise white mice with pink eyes, even without the pink-eyed gene, because once the mouse has “cc” all the other colors are erased.