THE LINEAR .\ERANGEMENT OF SIX SEX-LINKED 



FACTORS IN DROSOPHILA, AS SHOWN BY 



THEIR ^lODE OF ASSOCIATION 



A. H. STURTEVANT 



From the Zoological Laboratory, Columbia University 



HISTORICAL 



The parallel between the behavior of the chromosomes in 

 reduction and that of ]Mendelian factors in segregation was 

 first pointed out by Sutton ('02) though earlier in the same year 

 Boveri ('02) had referred to a possible connection (loc. cit., foot- 

 note 1, p. 81). In this paper and others Boveri brought forward 

 considerable evidence from the field of experimental embryology 

 indicating that the chromosomes play an important role in devel- 

 opment and inheritance. The first attempt at connecting any 

 given somatic character with a definite chromosome came with 

 AlcClung's ('02) suggestion that the accessory chi-omosome is a 

 sex-determiner. Stevens ('05) and Wilson ('05) verified this 

 by showing that in numerous forms there is a sex chromosome, 

 present in all the eggs and in the female-producing sperm, but 

 absent, or represented by a smaller homologue, in the male- 

 producing sperm. A further step was made when Morgan ('10) 

 showed that the factor for color in the eyes of the fly Drosophila 

 ampelophila follows the distribution of the sex-chromosome al- 

 ready found in the same species by Stevens ('08). Later, on 

 the appearance of a sex-linked wing mutation in Drosophila, 

 Morgan ('10 a, '11) was able to make clear a new point. By 

 crossing white eyed, long winged flies to those with red eyes and 

 rudimentary wings (the new sex-linked character) he obtained, 

 in F2, white eyed rudimentary winged flies. This could happen 



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