The three genes are se sepia ss spineless and ro rough

The three genes are se ( sepia ), ss ( spineless ), and ro ( rough ).

Wildtype 338

Sepia 96

Spineless 46

rough 156

sepia, spineless 173

sepia, rough 43

spineless, rough 114

sepia, spineless, rough 370

total 1336

What are the map distances?

Calculate the interference:

Solution

Answer : Map- Distance= [Number of recombinants/ Total]x100

Here Map-Distance= [700/1336]x100 = 0.52395x100= 52.395 cM

To measure interference, we first calculate the coefficient of coincidence (c.o.c.) which is the ratio of observed to expected double recombinants. Interference is then calculated as 1 - c.o.c=1-[observed number of double recombinant/ expected number of double recombinants]; C.o.c= 3.7x52.395=[193.8615]

Interference= 1- 193.8615= -192.8615