Stages of Meiosis

• Stages of Meiosis


  1. Interphase

  2. Meiosis I: Prophase I, Metaphase I, Anaphase I, Telophase I

  3. Interkinesis

  4. Meiosis II: Prophase II, Metaphase II, Anaphase II, Telophase II
• Meiosis I


  • Reduction division (diploid → haploid)
  • Homologous chromosomes separate
• Meiosis II

  • Sister chromatids separate
• Meiosis is preceded by interphase, in which DNA is replicated to produce chromosomes consisting of two sister chromatids
• A second growth phase called interkinesis may occur between meiosis I and II, however no DNA replication occurs in this stage
• Meiosis I: Prophase I


  1. Chromosomes condense

  2. Nuclear membrane dissolves

  3. Homologous chromosomes form bivalents

  4. Crossing over occurs
• Meiosis I: Metaphase I


  Spindle fibres from opposing centrosomes connect to bivalents (at centromeres) and align them along the middle of the cell
• Meiosis I: Anaphase I


  Spindle fibres contract and split the bivalent, homologous chromosomes move to opposite poles of the cell
• Meiosis II: Prophase II


  Chromosomes condense, nuclear membrane dissolves, centrosomes move to opposite poles (perpendicular to before)
• Meiosis II: Metaphase II


  Spindle fibres from opposing centrosomes attach to chromosomes (at centromere) and align them along the cell equator
• Meiosis II: Anaphase II


  Spindle fibres contract and separate the sister chromatids, chromatids (now called chromosomes) move to opposite poles
• Meiosis II: Telophase II


  Chromosomes decondense, nuclear membrane reforms, cells divide (cytokinesis) to form four haploid daughter cells
• The final outcome of meiosis is the production of four haploid daughter cells
• These cells may all be genetically distinct if crossing over occurs in prophase I (causes recombination of sister chromatids)