the frequency of silver stain of the nucleolus organizer regions ( nor 's ) an indicator of the transcriptional activity of the dnar , and the frequency of the association between acrocentric chromosomes ( a.a.c . ) , possible indicator of the non-disjunction risk , were studied in the chromosomes in metaphase of eight married couples with regular 21 trisomy children , five couples that have had consecutive miscarriages and fifteen control normal persons , eight men and seven women .
C0008059
children
C0027361
persons