+  + + 642
cv f y 368

cv f + 67
+  + y 130

cv + y 280
+  f + 350

+  y f 20
cv + + 35


cv - f = 280+350+20+35/1892 = 0.36 = 36 m.u. 

f  - y = 280+350+67+130/1892 = 0.43

cv - y = 20+35+67+130/1892 = 0.13

What you need to do then is do all strains and then do averages of all.  Because you're going to plot a map of the location of the genes and compared it to what's in the book, you need to average the resulting