370 



GENES MODIFYING NOTCH. 



Inspection of table 13 shows no significant correlation between the 

 kind of Notch shown by the F2 mother and the presence in it of the 

 bent chromosome derived from the black pink bent stock; for six F2 

 short Notch females had this bent chromosome, four did not; six F2 

 intermediates did not have it and two F2 did have it. There is no 

 correlation with black or pink either, hence there were no dominant 

 autosomnal modifiers in black pink bent stock. 



Table 13. — F2 Notch 9 by black pink bent cf. 



RECOMBINATION OF BENT AND SHORT NOTCH. 



As a matter of cm-iosity, largely, the possible interaction of ''bent" 

 in double dose on Notch was determined. Flies of the desired recom- 

 bination were made by crossing bent males to short-Notch females and 

 then by breeding the Fi Notch females to their brothers. Amongst the 

 F2 flies were pure bent females that were also Notch. These showed 

 the wddest possible range of modification as does the bent character 

 itself. In extreme cases, as shown in figure 95, the wing is as narrow as 

 stumpy wings (see Critique of Theory of Evolution, p. 11, figure 5, 

 c, d). It is noticeable, too, when looking through such a series, that 

 the extent to which the bent factor manifests itself in other ways, such 

 as in the shortening of the legs, is a sort of index of the extent to which 

 the wing is affected. This might, on first thought, be interpreted as 

 furnishing evidence in favor of the view that the extent to which a 

 character develops may be an index of the quantity of the gene present 



