1 Premeiotic G2 in a diploid lily pollen mother cell. Four nucleoli are visible; chromatin is relatively uncondensed except for small segments of heterochromatin.

Metaphase II in a diploid lily. The chromosomes of both nuclei are lined up on the metaphase II plates.

Anaphase I in a diploid lily pollen mother cell. Homologs have separated and chromosomes, led by their kinetochores are moving to the poles.

Telophase I in a diploid lily. Chromosomes have reached the poles and are beginning to decondense in the two resulting nuclei.

2 Prophase I of meiosis , leptotene substage in a diploid lily pollen mother cell. Four nucleoli are visible; chromatin has condensed into uniformly thin threads.

Prophase II in a diploid lily. The two cells produced by the first meiotic division are now separated by a cell wall. The chromosomes are condensing.

Anaphase II in a diploid lily. The chromatids have separated and are moving to opposite poles in both nuclei.

Metaphase I in a diploid lily pollen mother cell. The nuclear envelope is gone and the 12 bivalents can be seen lined up on the metaphase I plate. Counting from the top left and moving to bottom righ...

Prophase I of meiosis, diakinesis substage in a diploid lily pollen mother cell. Nucleoli are not visible. The 24 chromosomes have condensed, and are each paired with their homolog to form the 12 bi...

Model of the structure of the synaptonemal complex (SC) in Drosophila females based on EM immunolocalization of SC components C(3)G and C(2)M.