In meiosis I, which phase precedes the separation of homologous chromosomes?

In meiosis I, which phase precedes the separation of homologous chromosomes?

• A. Prophase I
• B. Anaphase I
• C. Metaphase II
• D. Telophase II

Answer: (B)

The phase just before the separation of homologous chromosomes in meiosis I is metaphase I. In metaphase I, homologous chromosomes pair up as tetrads and align at the cell’s equator, with spindle fibers attached to kinetochores. This positioning, along with chiasmata that hold the homologs together after crossing over in prophase I, sets the stage for the actual separation that occurs in anaphase I, when the homologous chromosomes are pulled to opposite poles while sister chromatids remain joined. Prophase I happens earlier, enabling crossing over; metaphase II and telophase II occur in meiosis II after the separation of homologs.

The phase just before the separation of homologous chromosomes in meiosis I is metaphase I. In metaphase I, homologous chromosomes pair up as tetrads and align at the cell’s equator, with spindle fibers attached to kinetochores. This positioning, along with chiasmata that hold the homologs together after crossing over in prophase I, sets the stage for the actual separation that occurs in anaphase I, when the homologous chromosomes are pulled to opposite poles while sister chromatids remain joined. Prophase I happens earlier, enabling crossing over; metaphase II and telophase II occur in meiosis II after the separation of homologs.