IIS PHYSIOLOGICAL GENETICS 



2. As just mentioned, there is a similar phenomenon at the 

 other end of the scries: No-wing/ + 18 not of Wild type but shows 

 a certain percentage of scalloped individuals (1.3 per cent in 

 Mohr's case, more in (Joldschmidt-Hoener's counts). As Fig. 24 

 shows, this is shifted by the dominigenes to 100 per cent. In the 

 usual language, this means that the extreme allele No-wing is 

 somewhat dominant. If viewed in connection with the fore- 

 going facts, it has a very different meaning, as it fits now into 

 an orderly series. We know already (see page 28) that the 

 scalloping effect is produced by destruction of already existing 

 wing area, presumably by insufficiency of some growth substance 

 or by accumulation of some lytic stuff. Let us now assume, 

 adapting a deliberation of Mohr (1932) to the new body of facts, 

 that the amount of growth substance — to use only this possi- 

 bility; it could be just as well presented for lysis — produced by 

 the alleles could be measured and that the threshold for the 

 production of Wild type would be 40. (This method of analysis 

 goes back to Goldschmidt's treatment of the allelomorphic sex 

 genes in Lymantria since 1911; it has been used since, besides in 

 work with sex-genes, by Wright (1925) for the series of coat 

 colors in guinea pigs; by Stern (19296), for the bobbed series; 

 by Ogura (1932), for the molting genes of the silkworm; and 

 by Mohr (1932), for the vgr-series.) The different types of 

 scalloping would then be produced by values below 40, i.e., 

 insufficiencies, and these values may be read from a diagram like 

 Fig. 20. Using an arbitrary basis, Mohr makes the follow- 

 ing evaluation: No-wing = 6, vestigial = 10, notched = 15, 

 nicked = 22, Wild = 30 for one gene. From this the compounds 

 and heterozygotes may be calculated and are, according to Mohr: 



vg Nw vg vg vg n ° vg no vg ni vg no vg ni + vg ni + rg ni + + + 



VQ NV, jjgSw V g p gS W „g yg.V V V gUO „g „^.V W pg nO yg ygni vg nO vg ni _|. 



12 lt> 20 21 25 28 30 32 36 37 40 44 45 52 60 



Wild type 



This corresponds, of course, to the diagrams Fig. 20, 24 and 

 shows the same orderly behavior and the series of different Wild 

 types beyond the threshold of 40. Now, if we apply this 

 enumeration to the problem of dominance in the series, we see 

 that the combined action of a heterozygote or a compound 



