Meiosis in Sxr male mice: II. Further absence of cytological evidence for a Y-autosome rearrangement in sex-reversed (Sxr) mice.

If the sex-reversal factor (Sxr) in mice is represented by a segment of the Y chromosome translocated on to an autosome, this segment might be expected to show some evidence of attempted pairing with the normal Y chromosome at the first meiotic division. Our failure to find such evidence in a light microscope study of the silver-stained pachytene spermatocytes from Sxr/4, XY males further supports existing cytological information that the factor is more likely to be represented by an autosomal dominant gene mutation.