Multiple copies of Sly and Asty/Asty(rec) map to MSYq. (a, b) Southern of EcoRI digested DNAs showing hybridization of Sly probe MTnH-K10 and Asty exon 4 probe, respectively, to multiple male specific bands, with reduced hybridization to all bands in 2/3MSYq- males. (c, d) Southern of EcoRI-digested DNAs from 2/3MSYq-, 9/10MSYq-, and MSYq- males together with control XYRIII, showing reduced hybridization in 2/3MSYq- males and an apparent absence of hybridization to Y specific bands in the males with more extensive MSYq deficiency. (e) Two week exposure of a Southern blot of EcoRI digested DNAs from 9/10MSYq- and MSYq- males together with XO and XX females, and an underloaded XYRIII control. X derived fragments now cross-hybridize with the Sly probe (dosing with the number of X chromosomes), but in addition there are at least three male specific bands (outlined) retained in the 9/10MSYq- males that are absent in the MSYq- males.