SYNAPTONEMAL COMPLEX IN THE XY PAIR OF AKODON-AZARAE

Three-dimensional reconstructions of the XY chromosomal pair in spermatocytes of Akodon azarae show that the ultrastructural axes of the X and Y chromosomes pair partially to form a long synaptonemal complex. The differential (unpaired) region of the X axis shows an unusually long and permanent splitting into two elements, which form an anomalous synaptonemal complex. The chromatin of the XY body is less closely packed than the autosomal chromatin during all synaptic stages. The length ratio of the X and Y axes differs from the length ratio recorded for normal, somatic X and Y chromosomes. © 1979, Japan Mendel Society, International Society of Cytology. All rights reserved.