Preleptotene chromosome condensation stage in human foetal and neonatal testes.

A preleptotene stage of chromosome condensation analogous to that already described in various plants and in the oocytes of several animal species has been observed in the human foetal testis. Contrary to what has been previously described, this stage in the testis is not followed by decondensation leading to leptotene filaments. This observation underlines the problem of the precise significance of this stage and its relation to initiation of meiosis. It is suggested that meiosis may be initiated during this condensation phase and that the male germ cell, despite its XY chromosome constitution, tends to evolve towards meiosis. This proposal pleads in favour of both the role of somatic cells in the inhibition of meiosis in the male foetus and the role of environmental factors rather than genetic constitution of the germ cell in meiotic induction.