I'd like to point out a couple of problems with the Dp(1;f)y+ entry.
Roberts (1969; FBrf0020571) used "Dp(1;f)y+" to describe a class of aberrations recovered after irradiating X chromosomes carrying y+ on the right arm.  These chromosomes were recovered repeatedly in his screens.  "Dp(1;f)y+" is really a generic category rather than the symbol for one specific chromosome, but it was listed in Lindsley and Zimm (FBrf0066905) as an aberration, so it's still in FlyBase as if it represents a unique chromosome.
The other references in the Dp(1;f)y+ entry refer to a unique chromosome duplicating 11DF to 12B7 and a segment from the X tip carrying y+. Bloomington currently has a stock with this Dp. Its origin and structure are obscure. FBrf0078125 cites Bruce Baker's lab as their source, but Bruce thinks it may have originated in George Lefevre, Jr's lab. FBrf0074917 gives no source, but the lead author Susan Zusman agrees that Lefevre is the likely discoverer. Based on the fact that it's a y+-marked free Dp, it seems likely that it was induced as a 2B7;20F deletion within the Ts(1Rt;YSt) segregant of a T(1;Y) with a 11DF;YS breakpoint.  Since most translocations used for such screens were derived from Dp(1;Y)y+ or Dp(1;Y)BSYy+, it would explain the presence of y+. Of course, this is just my guess...
The 11DF;12B7 duplication was originally called Dp(1;f)y+wy+, because it rescues wavy (wy) mutant phenotypes. It seems reasonable to use this name in splitting the current entry and to retain Dp(1;f)y+ for Roberts' duplications.
Thanks!
Kevin
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Kevin Cook, Ph.D.               
Bloomington Drosophila Stock Center
Department of Biology           
Indiana University