Complete autosomal chromomere maps of human early and mid/late pachytene spermatocytes

Specific identification of each bivalent of human spermatocytes at early and mid/late pachytene was obtained from chromomere maps developed by analyzing complete, well-spread cells from five subjects aged 31-49. The total number of chromomeres on the early autosomal bivalents was 499 and 386 at the mid/late stage. Regional analysis revealed more chromomeres at early pachytene than at mid/late, with 12 exceptions having equal numbers. Correspondence of chromomeres with mitotic prometaphase G-bands was found in all bivalents. Four chromomeres were found in region 1 of the 9q at early pachytene and two at mid/late. Differences between the map for chromosome no. 10 observed in this study and others were noted.