Synaptonemal complex analysis in oocytes and spermatocytes of threespine stickleback Gasterosteus aculeatus (Teleostei, Gasterosteidae).

A surface-spreading synaptonemal complex (SC) technique was employed to analyze spermatocytes and oocytes of stickleback, Gasterosteus aculeatus, in order to visualize the process of chromosome synapsis. The mean SC length was 150 +/- 18 microm in three males and 143 +/- 12 microm in one female analyzed. A representative SC karyotype with 21 bivalents was also presented. Each SC had lateral elements of equal length. No bivalent displaying the atypical synaptic behaviour which is often associated with heteromorphic sex chromosomes was observed neither in males nor in the female analyzed.