LINKAGE 67 



ywabjvms rfb' 

 YWABi VMS RFB' 



A number of females of this type have been made 

 up by Muller. The next formula shows the kinds of 

 eggs that were produced by one of these females and 

 the numbers of each kind that were produced. 



Non-crossovers : 



y w a bj v m s r f b'-6. 

 Y W A Bi VMS R F B'- 8. 



Single crossovers: 



YWabi vms rfb' -2. 



YWABj vms rf b'-2. 



y w a b; VMS R F B'- 2. 



YWABj Vms r f b'-l. 



YWABi VMS r f b'-l. 



ywab; vms RF B'- 1. 



Double crossover: 

 y w a b s VMS RFb'-l. 



Counts of over 600 offspring from females of the 

 same type have given similar results. The character- 

 istic method of interchange here demonstrated may 

 perhaps be better realized by contrasting the com- 

 binations just given with the following, which illus- 

 trate types of eggs found not to be produced by such 

 females 



yWaBi VmS rfB' 

 Y W a bi Vms RfB' 



It is not supposed, however, that the per cent, of 



