Fig. 3.

Recombination in XSxr ^bY* males. (a) The sex chromosomes of XSxr ^bY* males showing the complex Y*PAR and associated X-derived centromere, note that the original Y centromere is inactive. (b) PAR-PAR recombination arising from parasynapsed and staggered associations—note that the dicentric X and YSxr ^b (with inactive Y centromere) recombinant chromosomes are prone to loss at MI thus generating “O” gametes and are not present in the offspring. (c) Yp-Sxr ^b recombination with expanded views showing the Y gene content of the paired segments and potential crossovers—no recombinants were obtained from crossover 2, and recombinants from crossover 4 could not be detected due to a lack of markers. (d) The four types of recombinant from crossovers 1 and 3. (e) Bar chart of non-recombinant and recombinant frequencies. “Other n = 4” comprises one animal from an XΔSxr ^b gamete and three from Y*^ΔΔSxra gametes (generated by crossover 3)