the ag-stainability of the nors , an indicator of the transcriptional activity of the r-rna genes , is present during the meiotic prophase until pachytene and is absent during the remainder of the meiotic prophase , to reappear during the first stages of spermiogenesis and then disappear again during the elongation phase of the spermatids .
C0040649
transcriptional
C0035668
rna