Can you explain the full process of meiosis 1?

Dear Student,

Here is the answer to your question,

• Meiosis I is divided into 4 phases.

• Prophase I − longest phase and is further sub-divided into 5 phases
  • Leptotene − Condensation makes chromosomes become distinct and compact.
  • Zygotene − Homologous chromosomes start pairing together by a process called synapsis to form a complex structure called synaptonemal complex. Two synaptonemal complexes further form a complex called bivalent of tetrad.
  • Pachytene − Longest phase of prophase I
    Recombination nodules appear in this stage at the sites where crossing over has to take place between non-sister chromatids of homologous chromosomes.
  • Diplotene − Synaptonemal complex dissolves and recombinants separate from each other except at crossover sites to form X-shaped structure called chiasmata.
  • Diakinesis − Chiasmata terminalises and chromosomes condense. Mitotic spindle assembles and nucleolus and nuclear envelope disappear.
• Metaphase I − Bivalent chromosomes align on the equatorial plate and spindle fibres appear and attach to the homologous chromosomes.
• Anaphase I − Homologous chromosomes separate; sister chromatids remain attached at their centromeres.
• Teleophase I − Nuclear membranes and nucleolus reappear. Cytokinesis follows.
• Interkinesis − Stage between meiosis I and meiosis II