438 



Genetics of Sex Determination 



However, a number of cases are known in which XY individuals be- 

 come more or less hermaphroditic (subandroecious) and, as it seems, 

 more rarely, XX individuals may show male characteristics, are sub- 

 gynoecious. In addition, it was found a long time ago by Strasburger 

 that females infected with Ustilago will develop male characters, 

 which is a very important fact to be kept in mind. 



The authors mentioned above studied sex determination in this 

 plant with the aid of polyploid combinations, thus paralleling Bridges' 

 work in Drosophila. Without going into the genetic technique for 

 producing the combinations, we give the results in table 5, in which 

 the corresponding Drosophila combinations are entered (A = set of 

 autosomes; ^ = intersex in Drosophila, subandroecious in Melan- 

 drium). 



TABLE 5 

 (From M. Westergaard, 1953) 



The table shows that in Drosophila the balance of male deter- 

 miners somewhere in the autosome set versus female determiners in 



