Figure 7.

(A–D) Phase-contrast images of four examples of the same sperm LBC derived from R. pipiens sperm heads injected 2 d previously into a Xenopus GV. Near one end of this chromosome is an unusually large loop with a prominent granule at its base (arrowheads). The loop is single, as expected for an unreplicated chromatid. (E) Same field as D, DAPI stain to show the prominent DNA axis. (F) Sperm LBC 2 d after injection of zebrafish D. rerio sperm heads into a Xenopus GV. Sample is stained with mAb K121 against TMG. Arrowheads point to two loops with unusually heavy matrix.