During which phase of meiosis do the homologous chromosomes separate?
The Correct Answer and Explanation is :
Homologous chromosomes separate during Anaphase I of meiosis.
Explanation:
Meiosis is a type of cell division that reduces the chromosome number by half, leading to the formation of four genetically diverse haploid cells. It consists of two main stages: Meiosis I and Meiosis II. Each of these stages has distinct phases, and the separation of homologous chromosomes occurs during Meiosis I, specifically in Anaphase I.
- Prophase I: This is the first phase of Meiosis I, where homologous chromosomes (chromosomes that are similar in shape, size, and genetic content) pair up in a process called synapsis. These pairs, known as tetrads, undergo genetic recombination or crossing-over, where segments of chromatids are exchanged between homologous chromosomes. This process increases genetic variation.
- Metaphase I: In this phase, the homologous chromosome pairs align along the metaphase plate. Unlike in mitosis, where individual chromosomes align, the homologous pairs line up side by side during metaphase I.
- Anaphase I: This is the crucial phase where homologous chromosomes are pulled apart toward opposite poles of the cell. Each chromosome still consists of two sister chromatids, but the homologous chromosomes (one from the mother and one from the father) are separated. This reduction in chromosome number is essential for producing haploid cells. The sister chromatids remain attached at this stage.
- Telophase I: The separated chromosomes arrive at opposite poles, and the cell undergoes cytokinesis, resulting in two daughter cells, each with half the number of chromosomes (haploid).
After Meiosis I, Meiosis II follows, where the sister chromatids of each chromosome are separated, similar to the process in mitosis.
The separation of homologous chromosomes in Anaphase I is critical for ensuring that each resulting gamete (sperm or egg) has only one chromosome from each pair, allowing for proper genetic diversity during sexual reproduction.