Individualisation complexes form in the testes of Ts(1Lt;YSt)P7+Ts(YLt;3Lt)W27+Ts(1Rt;3Rt)W27 males at the elongated nuclear bundles and traverse caudally along the spermatid tails as in wild type, suggesting that spermatids are individualised. A large number of individualised spermatids are produced in the basal region of the testes. However, defective spermatids are degraded before entering the seminal vesicles.