Figure 5. Recovery of GSC nucleolar morphology, Y rDNA dominance and Y rDNA copy number in F₁ flies.

(A) Changes in GSC nucleolar morphology in F₁ flies from old parents, as a percentage of total GSCs scored (n, number of GSCs scored). p-value from chi-squared test is shown. (B) Nucleolar dominance in GSCs from day 0 and day 10 old F₁ testes assessed by SNP in situ hybridization. DAPI (blue), Y rRNA (green), X rRNA (red). The hub is denoted by (*). Bars: 5 µm. Co-dominant GSCs are indicated by red dotted lines, Y-dominant GSCs are indicated by yellow dotted lines. Arrows indicate X rRNA signal, thus co-dominance. (C) Nucleolar dominance in F₁ GSCs during aging, as a percentage of total GSCs scored (n, number of GSCs scored). Mean ±SD. P-value of t-test is shown. Note that X-only rRNA transcription was never observed, except for once (out of 770 cells) at day 0, which is included in the graph. (D) Ratio of Y:X signal intensity for the 18S rDNA from mitotic chromosome spread of germ cells in F₁ flies. Mean ±SD, t-test.