Genetics: Analysis and Principles 5th Edition by Robert Brooker

Exercise 7

In mice, a trait called snubnose is recessive to a wild-type nose, a trait called pintail is dominant to a normal tail, and a trait called jerker (a defect in motor skills) is recessive to a normal gait. Jerke mice with a snubnose and pintail were crossed to normal mice, and then the F 1 mice were crossed to jerker mice that have a snub nose and normal tail. The outcome of this cross was as follows:
560 jerker, snubnose, pintail
548 normal gait, normal nose, normal tail
102 jerker, snubnose, normal tail
104 normal gait, normal nose, pintail
77 jerker, normal nose, normal tail
71 normal gait, snubnose, pintail
11 jerker, normal nose, pintail
9 normal gait, snubnose, normal tail
Construct a genetic map that describes the order and distance between these genes.