Figure 4.

Trisomy IV is corrected. (A) Fluorescence images of the head/pharynx regions of adult worms bearing the transgenes used to generate the ABC trisomy IV strain. Bar, 10 μM. (B) Fluorescence images of DAPI-stained diakinesis nuclei showing six chromosome bodies in N2 wild-type and seven in ABC trisomy IV. Bar, 5 μM. (C) Punnett square showing expected genotypes resulting from a cross between an ABC hermaphrodite and a CB4856 diploid male without markers. Bar graph shows observed phenotypes of cross-progeny compared to expected frequencies from random (1:1) or 2.8:1 biased segregation. (D) F1’s from five broods of mated ABC hermaphrodites crossed with CB4856 males. Worms with single markers were observed 73.8% of the time, corresponding to a 2.8:1 bias of oocytes inheriting one copy:two copies of chromosome IV from the mother. (E) Punnett square showing expected genotypes resulting from ABC hermaphrodite self-progeny. (F) Observed frequencies of self-progeny, compared with expected frequencies with no correction in sperm, demonstrating that the phenotypically ABC worms are ABC trisomy IV rather than AABC tetrasomy IV. diplo, diploid; haplo, haploid; Obs., observed.