Surface spreading of synaptonemal complexes in locusts

Details are given of techniques for preparing surface spreads of locust spermatocytes for light and electron microscopy. The pachytene synaptonemal complex (SC) karyotypes of Locusta migratoria and Schistocerca gregaria are analysed and compared. Up to six different SCs can be identified in Locusta migratoria based on lengths, centromere positions, and possession of nucleolar organiser regions, but only two SCs are identifiable in Schistocerca gregaria. The total SC length is significantly greater in Schistocerca gregaria than in Locusta migratoria, and this difference is almost exactly proportional to the difference in the genomic DNA contents of the two species.