291 



SlXiKKtJATlON A.\l> KJ':('().MI'.lNATION OF THE (iENKS FOR TINGED, 

 niAMHK lU'FK. A\I» COIJAL IX DKOSOI'HH.A MELAN(K!ASTEK. 



|{()S('OE R. Hydk. 



From the Dcpiirl iiiciil of Iiiiiimiiolofiy. ScIkkiI of I lyfiiciic iiml rulilic 



IIc.illli. .!(.lms Hopkins I'liivcrsity. I'.altiiiKin-. 



Contoiits. 



1. Linkable of Imff iiiid liiif,'c(l. 



(a) Buff 9 hy imgi'do'. 

 (1)) Buff cT by tingfd 9 • 



2. lAwkniiv of l)Uff and blood. 



(a) Buff 9 by blood o'. 



(b) Buff cf by blood 9 . 



S. Linkajrt' of coral an<l tiii^'cd. 



(a) Coral 9 by tinged cf . 



(b) Coral cf by tinged 9 . 



4. LinkaRe of coral and blood. 



(a) (^oral 9 by blood cf. 



(b) Coral d" by blood 9 . 



;"). Linkajic of coral and buff. 



(a) Coral 9 by buffcT. 



(b) Coral cf by buff 9 • 



0. Linkage of tinged and blood. 



(a) Tinged 9 by blood cf. 



(b) Tinged c^ by blood 9 . 



7. Linkage of coral and eo.sin. 



(a) Eosin 9 by coral cf . 



(b) Eosin cf by coral 9 . 



5. Snunnary. 

 !). Literature. 



In a previous paper I reiwrted the origin of blood and tinged, two .sex- 

 linked eye mutants in Drosophila. Both mutants gave complete linkage 

 with white, eosin and cherry and consecpiently formed with the red of the 

 wild type a sextuple system of nudtiple allelomorphs. Safir and Lance- 

 field later reix)rted huff and coral, two other members of tliis sy.stem. as 

 shown by their linkage to white. T. H. Morgan has kindly supplied me 

 with stocks of buff and coral and this paper records the cond>inations made 

 with those two stocks to my stocks of blood and tinged.- The results of 

 these crosses bear out the expectation that, since l)lo()d and tinged are 

 allelomorphic to white and luiff and coral are allelomorphic to white, the 

 mutants buff, coral, tiiigeil and blood should show alleloinoriddsm to each 

 other. 



The evidence from such a .system is significant as it bears on the nature 

 of the change that takes place in the chromosomes of mutant stock.s. If the 

 different mutants are a result of losses of materials that lie at different 

 levels on the sex-chromosome, then the wild type eye should result in the 

 daughters on crossing any two of the.se mutants, since the daughter receives 

 two sex-chromosomes and each would restore the missing allelomorph of the 

 other. As a matter of fact the daughters from all combinations are com- 



