i;;s BEREDITY AND SEX 



carried by the female-producing sperm. The analysis 

 is then as follows: One "dose" of horns (H) in the 

 male produces horns, bui two doses are necessary for 

 the female. 



Hornless ? hX — hX 



Horned 6 H X — H 



As pointed out by Punnett a test of the correctness 

 of this interpretation is found by breeding the F\ 

 hornless female to a hornless male (of a hornless breed). 

 It is assumed that such a female carries the factors for 

 horns in a heterozygous condition ; if so, then half of 

 her sons should have horns, as the following analysis 

 -hows : 



F l Hornless $ HX — hX 

 Hornless S h X — h 



h X HX hornless $ 



hXhX hornless $ 



h H X horned S 



h h X hornless S 



