i 



DATA ON A PECULIAE MENDELIAN EATIO IN 

 DEOSOPHILA AMPELOPHILA 



JOSEPH LIFF 1 



A mutant with pink eyes was found by Professor T. H. 

 Morgan in the summer of 1910, in one of his culture 

 bottles which contained wild, red-eyed Drosophila. He 

 described it as follows : 2 



' ' The pink eye is more translucent than the red eye, but 

 of about the same general tone. It lacks the dark fleck 

 seen in the red and vermilion eye when the eye is exam- 

 ined with a lens. This black fleck changes its position as 

 the lens travels over the eye. The pink eye, P, is witli a 

 little experience easily distinguished from the other colors, 

 especially in newly hatched flies. When the fly gets old 

 the eye turns to a brown color very characteristic of this 

 type of eye. ' ' 



Pink was found to be recessive to red. The Mendelian 

 expectation in the F 2 , viz., three red to one pink, gave the 

 following (Morgan, 1911) : 



The expectation in either case was 3 : 1, but the num- 

 bers realized were' 18 : 1 and 5 : 1. 



In the spring of 1912 I repeated this experiment under 

 the direction of Professor Morgan in order to find 

 whether or not the above ratio would persist. The results 

 have already been published (Morgan, 1912), but a brief 

 summary is here reproduced for reference : 



1 From the Zoological Laboratory of Columbia University. 



2 Jour. Exp. Zoology, Vol. 11, No. 4, November, 1911. 



97 



