Mini Mouse consists of a red nose, and Mickey Mouse consists of a red nose too. They had some children and of their F1 half of the males had black noses, half the males had red noses and all of the females had red noses!
Mini was as well married to the other mouse named Timmy. Timmy had a black nose. Mini and Timmy had children and half of all their F1 had black noses, the other half had red noses. The red nose in a mouse is caused by the expression of R gene. The R gene has one intron. In black nosed mice, the R intron is not removed as these mice are missing a SnRP. This specific SnRP is expressed in noses of red nosed mice.
Describe these results by describeing how and why introns are eliminated and proved the genotypes of the Mini, Mickey and Timmy and also their children.