Fig. 1. Transient stretching of trailing chromosome arms is common during anaphase in crane-fly spermatocytes. (A-D) Selected frames from a time-lapse DIC recording of a primary spermatocyte in which arms of segregating partner half-bivalents stretched backwards during mid-anaphase. (A) The dichiasmic bivalent at metaphase. (B) The two half-bivalents began to segregate. (C) As anaphase progressed, trailing arms (arrowhead) of partners stretched backwards. (D) Partner arms retract as the half-bivalents continue moving polewards. Times are given in minutes and seconds. Bar, 5 µm (D). (E-H) Spermatocytes that were fixed in situ with glutaraldehyde. In each, arms of partner chromosomes are stretched backwards as if their telomeres were connected. The sex chromosomes normally lag at the spindle equator during anaphase in these cells and they are especially prominent in G and slightly in focus in E, F and H. Bar, 5 µm (H).

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