In my first litter i had 3 agoutis and 2 non agoutis. The father is a broken marked and the mother is a REW. One of the little black baby's tail is pink at the tip. Genetically what does this mean? All of the other mice have tails and feet that match there fur. I have been doing research on genetics and would like to know what gene causes the skin on the tail and feet to be different color?