Fig. 5. GFP images of cen1 in a rec7 homothallic strain in meiosis I. Meiosis was induced in strain A5, and the divisions were observed as described in Materials and Methods. Numbers on the left of each image represent time in minutes. (A) GFP signals arising from homologous chromosomes which eventually moved to the same pole, resulting in nondisjunction I. The arrow points to the chromosome moving to the same pole as its homolog. (B) Chromosome re-orientation in rec7. The arrow points to the chromosome that moved to the same pole as its homolog and subsequently re-oriented to the other pole. Scale bar: 10 µm.