470 Genetics of Sex Determination 



more or less the same as for diploid sex determination. Hartmann 

 insists upon the need of the AG factors. I think they are superfluous, 

 and the argument is the same as discussed above. Also in haploids a 

 F/M balance must be present, and both F and M can occur in different 

 potencies or valencies, as shown in what Hartmann termed "relative 

 sexuality;" this, in unicellular haplonts, which are simultaneously 

 sexual organisms and gametes, is the condition parallel to strong and 

 weak races in Lymantria, producing intersexuality in crosses. Corre- 

 spondingly, the explanation of relative sexuality is derived from the 

 Lymantria case, of course wath the difference that the haploid cells 

 are both gametes and sexual organisms. The chemical mechanism 

 which Moewus and Kuhn claimed for the action of F and M of 

 different valency has already been discussed (see III 5 C a aa). The 

 "valency" was a definite mixture — variable with different valencies — 

 of two sex-controlling stuffs (if this is true). Thus far, then, the 

 genetic theory is identical for the higher diploid organisms and the 

 haplonts. This includes also what Hartmann called "phenotypic sex 

 determination," since my criticism of this concept is directly applicable 

 to the haploid organism. The same applies also to the modifier actions 

 studied in haploids as mutant effects. Therefore there is no need to 

 go into the many details assembled in Hartmann's book, which is not 

 easily read on account of the cumbersome terminology, derived from 

 Correns' ideas and the failure to draw a clear line between sex deter- 

 mination and sex attraction (mating type). 



However, at one important point Hartmann's theoretical inter- 

 pretation, based upon the AG and realizator concept, is basically 

 different from what I believe to be the correct solution in harmony 

 with the theory of sex in diploid organisms. If Hartmann's interpreta- 

 tion is correct, the lower plants use a different mode of sex determina- 

 tion from that of the higher plants and animals. In order to under- 

 stand this, let us try first to derive the consequences for haploids (or 

 haploid phases) from the previous discussion (see Goldschmidt, 

 1929a). Assuming that the F/M balance mechanism works in the 

 same way as in diploids and that male heterogamety is present, we 

 see that the X-chromosomes can contain only F factors; and the auto- 

 somes, M factors. If the diploid condition were female, MMFF, the 

 haploid would be MF, just as in the post-meiotic eggs; that is, the 

 same balance makes this haploid a female. (This has been proved for 

 Drosophila by Bridges, 1925.) From the diploid male MMFf (f = O 

 or Y-chromosome ) two haploids would be derived (like gametes of a 

 diploid), MF = $ and Mi = $ . Here the male haploid would have 



