Figure 8.

Proposed Model for ZYGO1 Function during Early Prophase I.

In the wild type, accompanying homologous pairing, telomeres gradually aggregate from late leptotene to zygotene and finally are clustered into a typical bouquet at zygotene. Meanwhile, linear chromosomes gradually aggregate into a fused mass. The telomere bouquet and chromosome mass completely dissolve and homologous chromosomes are fully synapsed at pachytene. In zygo1, however, both the telomere bouquet and chromosome mass do not form. Although some chromosomes initiate pairing and synapsis, full-length chromosome pairing and synapsis are not completed. Finally, crossover formation is restricted to the partially synapsed region of chromosomes in zygo1.