Individuals homozygous for linked  ‘p’ and 'q' genes were crossed with wild type (+ +). The ${\mathrm{F}}_1$hybrid thus produced was test crossed. It produced the progeny in the following proportion:
++=800
pq= 900
+p= 100
+q= 200
Calculate the distance between p and q genes present on the same chromosome.
 

• A

  20 map units

• B

  15 map units

• C

  10 map units

• D

  30 map units