120 " Ounandromorphism" and Kindred Problems 



appears to me to be disproved by the existence of gynandromorph 

 hybrids, some halved, in which both the male and female portions show 

 precisely similar mixture of chai-acters derived from both parents. 



The other theories rest largely on the supposition that sex itself is 

 a Mendelian unit character. 



This supposition is based on numerous breeding experiments in 

 cases of sex-limited inheritance. In insects, with a few exceptions such 

 as Drosophila, and in birds maleness appears to be a homozygous 

 recessive and femaleness a heteroz3'gous dominant. The character for 

 sex is supposed to be carried by a special chromosome. Secondary 

 sexual characters are probably also unit characters but are closely 

 linked with the primary characters and it is thought that they are 

 present in the same chromosome. 



Breeding experiments by Brake repeated and amplified by Gold- 

 schmidt with various strains of Lymantria dispar Linn, and its larger 

 and more strongly marked variety Lymantria dispar var. japonica 

 Motsch. have produced large numbers of gynandromorphs of three kinds 

 distinct in their external appearance and in their internal structure. 

 These are female and male gjmandromorphs and " weibchen-mannchen." 



These were always absent in certain crosses and present in definite 

 proportions in others. 



By making certain assumptions the numbers were found to follow 

 Mendel's law. 



Goldschmidt uses the following symbols : 



F = female sex factor. 



f = its recessive. 



M = male sex factor. 



m = its recessive. 



= the factor for secondary sex characters of female. 



g = its recessive. 



A = the factor for secondary sex characters of male. 



a = its recessive. 



The male factor M is more potent than the female factor F but the 

 potency is such that two female factors FF are more potent than one 

 male factor M. The relation between G and A is similar. For con- 

 venience Goldschmidt gives the following arbitrary values in figures : 



.4=60, G = 40, ^yl = 120, GG = SO. 



