SA-2^Z3-0317/SA-2^Z3-2138 males exhibit defects in chromosome segregation (random segregation of sex chromosomes) and conjunction during meiosis I; more numerous and smaller chromosomes during late S6 stage and prometaphase I; and high variation in the DNA content per spermatid nucleus in spermatid cysts compared to controls.

SA-2^Z3-0317 mutants show elevated frequencies of autosomal and sex chromosome nondisjunction. Analysis of mutant spermatocytes shows that nondisjunction is limited largely to meiosis I. Premeiotic and meiotic homolog pairing are normal. The earliest observable phenotype is that of "territory expansion" in late G2, with homologous chromosomes being at a greater distance from one another than in wild-type spermatocytes. SA-2^Z3-0317 spermatocytes show incomplete chromatin condensation and form up to eight large clumps of chromatin form by metaphase I, instead of the one central mass observed in wild type. The clumps represent bivalents and univalents, consistent with a defect in formation or maintenance of bivalents. In early anaphase I, chromosomes are distributed unevenly and asymmetrically along the spindle. In late anaphase I, there is a high frequency of laggards and polar chromatin masses of unequal size, indicating high frequency of nondisjunction.

SA2^{βTub85D.C.EGFP}, SA2^Z3-2138/SA2^Z3-0317 has sex chromosome | spermatogenesis phenotype, suppressible | partially by mod(mdg4)^{βTub85D.mnm.C.EGFP}

SA2^{βTub85D.C.EGFP}, SA2^Z3-2138/SA2^Z3-0317 has spermatocyte | spermatogenesis phenotype, suppressible | partially by mod(mdg4)^{βTub85D.mnm.C.EGFP}

SA2^{βTub85D.C.EGFP}, SA2^Z3-2138/SA2^Z3-0317 has testis | adult stage phenotype, suppressible | partially by mod(mdg4)^{βTub85D.mnm.C.EGFP}

SA2^Z3-2138/SA2^Z3-0317 has sex chromosome | spermatogenesis phenotype, non-suppressible by mod(mdg4)^{βTub85D.mnm.C.EGFP}

SA2^{βTub85D.C.EGFP}, SA2^Z3-2138/SA2^Z3-0317 has autosome | spermatogenesis phenotype, non-suppressible by mod(mdg4)^{βTub85D.mnm.C.EGFP}

SA2^Z3-2138/SA2^Z3-0317 has autosome | spermatogenesis phenotype, non-suppressible by mod(mdg4)^{βTub85D.mnm.C.EGFP}

SA2^Z3-2138/SA2^Z3-0317 has spermatocyte | spermatogenesis phenotype, non-suppressible by mod(mdg4)^{βTub85D.mnm.C.EGFP}

SA2^Z3-2138/SA2^Z3-0317 has testis | adult stage phenotype, non-suppressible by mod(mdg4)^{βTub85D.mnm.C.EGFP}

SA2^{βTub85D.C.EGFP}, SA2^Z3-2138/SA2^Z3-0317 has nucleus | spermatogenesis phenotype, non-suppressible by mod(mdg4)^{βTub85D.mnm.C.EGFP}