The meiotic pairing behaviour in human spermatocytes carrier of chromosome anomalies and their repercussions on reproductive fitness. I: Inversions and insertions. A European collaborative study.

The synaptic behavior of pachytene chromosomes was studied in men heterozygous for inversions and one inversion-insertion by analysis of synaptonemal complexes at the electron microscopy level. The human meiotic data were collected from European laboratories in order to test the current theories and to link the arrest of spermatogenesis and the risk of chromosome imbalance to the mode of pairing and their consequences. The breakpoint location would allow to predict the synaptic and recombinational behavior of chromosome aberrations and particularly the risk of aneusomie de recombinaison in the progeny of inversion carriers.