Subject: Dp(1;Y)y+g+ cytology Abe Schalet generated Dp(1;Y)y+g+ by irradiating C(1;Y)6, In(1)sc29 to delete most of the X chromosome (see /reports/FBab0003218.html). I analyzed polytene squashes of Dp(1;Y)y+g+ and determined that the proximal breakpoint lies in X heterochromatin and the distal breakpoint likely lies in 12A. The 12B4,5, 12C1,2 and 12C4,5 doublet bands were clearly present. The 12B1,2 doublet appeared to be tightly juxtaposed to the chromocenter in several spreads. My squashes of the duplication verified that the distal breakpoint in the In(1)sc29 precursor chromosome was between 1A5,6 and 1B1,2 and the proximal breakpoint was between 13A1,2 and 13A5,6. The structure of Dp(1;Y)y+g+ is X tip to 1A6-1B1 | 13A2-5 to 12A | X heterochromatin | YL - Y centromere - YS tip Genetically, the distal extent of the medial segment is limited by the male diplolethality of the Hdl locus in 12A. Minimally, the medial segment extends distal to garnet in 12B.
