Electron microscopy of meiosis in Drosophila melanogaster females: II. The recombination nodule--a recombination-associated structure at pachytene?

The recombination nodule is a transient structure present during pachytene in intimate association with the synaptonemal complex. The total numbers of these structures per nucleus and their locations along the bivalents correspond to the total numbers and distributions of genetic exchanges. It is suggested that this structure may be involved in the recombination process.