ANOTHER CASE OF MULTIPLE ALLELOMORPHS. 233 



Yellow 9. Spot 9. Yellow <?. Spot & 



44 45 41 45 



This is the expected result for this combination. 



The body-color black belongs to our second group of linked 

 factors. A spot female was mated to a black male. The 

 daughters were gray without trace of spot, the sons were spot. 

 Female producing sperms bring in the normal allelomorph for 

 spot (Y), which, with the normal allelomorph for black (B), 

 gives gray. The sons are spot because the male receives his 

 sex chromosome from his mother. The formulas for the FI and 

 FZ generations are the following: 



Spot 9, y a By,B. 

 Blacky, Yb b. 



( Gray 9 , y,B Yb. 

 \ Spot d\ y s Bb. 



y g BYby 8 bYB, Eggs of \ 

 y s B y s b -B b, Sperm of / 



y s By s B, spot. y s B B, spot. 



Yby s B, gray. Yb B, gray. 



y s by s B, spot. y s b B, spot. 



YBy s B, gray. YB B, gray. 



y s By s b, spot. y s B b, spot. 



Yby s B, black. Yb b, black. 



y s by s b, spot black. y s b b, spot black. 



YBy s b, gray. YB b, gray. 



The F 2 expectation is 3 gray, 3 spot, I black, I spot black, and is 

 the same for the male and the female classes which are counted 

 together in the following F 2 results for this cross. 



Fs Females. F2 Males. 



Gray. Spot. Black. Spot Black. 



133 90 47 39 



The double recessive is spot black, which corresponds in color 

 to yellow black or "brown" of earlier papers. The light spot 

 shows here even more strikingly, because of contrast, than in the 

 simple " spot " itself. 



