CHROMOSOMAL-ANOMALIES AND DISTURBANCE OF TRANSCRIPTIONAL ACTIVITY AT THE PACHYTENE STAGE OF MEIOSIS - RELATIONSHIP TO MALE-STERILITY

Morphological analysis of pachytene spermatocytes obtained from male m ice carrying three chromosomal rearrangements - a Robertsonian translo cation. Rb(X-2)2Ad; an autosomal reciprocal translocation, T(16;17)43H ; and a tertiary trisomic. Ts(113)70H - demonstrated frequent associat ion between the XY bivalent and the T43H and T70H translocation chromo somes. Quantitative autoradiographic data revealed that the normal tra nscriptional inactivity of the XY bivalent was not significantly distu rbed, in contrast to that of the 16;17 quadrivalent and the extra 1(13 ) marker chromosome. These results are interpreted as an extension of the XY inactivation process to the associated autosomes and discussed in relation to male sterility.