Suppose you have a line of mice that has cytologically distinct forms of chromosome 4. The tip of the chromosome can have a knob (called 4K ) or a satellite (4S) or neither (4). You cross a 4K/4S...

Suppose you have a line of mice that has cytologically distinct forms of chromosome 4. The tip of the chromosome can have a knob (called 4^K
) or a satellite (4^S) or neither (4). You cross a 4^K/4^Sfemale with a 4/4 male and find that most of the progeny are 4^K/4 or 4^S/4, as expected. However, you occasionally find some rare types as follows (all other chromosomes are normal):

a. 4^K/4^K/4