IMMUNOCYTOCHEMICAL LOCALIZATION OF DNA IN SYNAPTONEMAL COMPLEXES OF RAT AND MOUSE SPERMATOCYTES, AND OF CHICK OOCYTES

The distribution of DNA in synaptonemal complexes of rat and mouse spe rmatocytes, and of chick oocytes was investigated by immunogold electr on microscopy. Except for a few specific sites, DNA was not immunoloca lized in the space between lateral elements of the complex. Some label ed fibrils connecting the lateral elements with the central element we re observed associated with recombination nodules or near them. Howeve r, other labeled fibrils in the space between lateral elements did not appear to present any relationship to recombination nodules. The immu nocytochemical approaches used here confirmed the presence of signific ant amounts of DNA in the lateral elements as previously indicated by preferential DNA staining methods. Furthermore, our findings support t he view that recombination nodules are the site of chiasma formation.