Chapter 5, Problem 48P

Figure 5.29 shows mitotic recombination leading to single spots or twin spots occurring in the G₂ stage of the cell cycle (after the chromosomes have replicated). However, because it usually is initiated by rare, random events of chromosome breakage, mitotic recombination can also take place in G₁, prior to S phase. Redraw Fig. 5.29 with mitotic recombination taking place in G₁ rather than G₂, and demonstrate why any such event could not yield single spots or twin spots.