40 SEX-DETERMINATION 



conditions of the male- and the female-determining factors 

 of the different races form an orderly quantitative series in 

 regard to their effect and that different possible combina- 

 tions behave exactly as if the different degrees of strength of 

 these genes could be expressed in numerical values. 



The genetical basis of sex and intersexuality as under- 

 stood by Goldschmidt is given by the amount of balance 

 or imbalance between M and F at the beginning of develop- 

 ment. In the uneventful differentiation of the normal male 

 M is always effectively in excess of F; in the case of the 

 normal female F is at all times effectively in excess of M, 

 but in the development of the intersex the relationship of 

 M and F is disturbed; M (or F) overtakes and replaces 

 F (or M) at some point — the turning-point or switchover. 

 The effect of this genie situation is that at a certain moment 

 in development the switch-over occurs and the control of 

 the remaining events in sexual differentiation is shifted from 

 the F to the M genes, or vice versa, and the time of occur- 

 rence of this event is the simple function of the relative 

 degree of balance or imbalance between F and M. It would 

 seem that M and F respectively are responsible for sex- 

 determining reactions which proceed with a velocity pro- 

 portional to the strength or valency or quantity of these 

 genes; that the quicker reaction controls the sexual differ- 

 entiation and that the two curves of M and F reactions may 

 have points of intersection, that is, at the switch-over, if the 

 quantities of M and F are not properly matched. If this is 

 so, then it should be possible to produce abnormal forms by 

 changing the relative velocities of these two reactions within 

 a pure normal race, through the differential action of 

 temperature, for example. This Goldschmidt has done with 

 positive results, producing intersexuality by the action of 

 extreme temperature within a pure race. 



Winge (1937) offered an alternative explanation of the 

 observations that required Goldschmidt to postulate cyto- 

 plasmic inheritance. He suggested that the X-chromosome 

 contains a preponderance of male-determining genes, 

 strong (M 50) in the Japanese variety and weak (M 10) in 

 the European; that the Y has a preponderance of female- 



