Page 10: Another Metaphase I and Anaphase I


Metaphase I (top) and anaphase I (bottom) in Tradescantia (n=6). In the top figure, the large arrows point to two unpaired homologues in metaphase I; each is a univalent. The two homologues probably synapsed, but were not held together after pachynema because there was no crossing over between them, thus no formation of chiasmata. We know that the two univalents are still in metaphase I and not in early anaphase I because the chromatids have not begun to repel each other as seen in the anaphase I chromosomes (small arrows) in the bottom figure.