Fig. 1.

Origin of Sxr variants. (a) Wild type XY. (b) Duplication and translocation of Yp created Sxr ^a. (c) PAR-PAR recombination in XYSxr ^a males generates the XSxr ^a chromosome. (d) An unequal crossover in an XSxr ^aYSxr ^a male created the Sxr ^b deletion variant. (Color codes: Red = PAR; Blue = non-PAR X; Dark green = non-PAR Y except Sxr ^b; Light green = Sxr ^b; Yellow = Zfy1; Orange = Zfy2; Orange/Yellow = Zfy2/1 fusion gene.) ^* Rbmy copy number estimates based on information provided by Soh et al. (2014) and Mahadevaiah et al. (1998)