Q. The Neurospora cross was made between a strains that carried mating type A and mutant allele arg-1(arg) and another strain the carried mating-type a and the wild type arg-1 (+) gene. Four hundred linear octads were isolated and they fell into the 7 categories specified in the table below.

a. Label each class and PD, NPD or TT

b. Are the genes linked?

c. What are the map distance between these genes and centromere?

Class 1 Class 2 Class 3 Class 4 Class 5 Class 6 Class 7
A arg A + A arg A arg A arg A + A +
A arg A + A + a arg a + a arg a arg
a + a arg a arg A + A arg A + A arg
a + a arg a + a + a + a arg a +
127 125 100 36 2 4 6