What is Meiosis?
Meiosis is a type of cell division which produces four daughter cells. Each of these cells consists of half the number of chromosomes present in the parent cell, as in the production of gametes and plant spores.
A. Meiosis I:
Here, the pairs of homologous chromosomes are separated and a special cell division takes place reducing the cell from diploid to haploid.
Meiosis I is also divided into the following stages,
- Prophase I
- Prometaphase I
- Metaphase I
- Anaphase I
1. Prophase I:
In Prophase I homologous chromosomes pair and exchange DNA and recombinant chromosomes are formed.
Five Phases of Prophase I:
2. Prometaphase I:
In prometaphase I formation of spindle apparatus takes place and chromosomes are attached to spindle fibres by kinetochores.
3. Metaphase I:
Here, the homologous pairs of chromosomes are arranged in a double row along the metaphase plate. These chromosomes are randomly arranged along the metaphase plate.
4. Anaphase I:
In this phase separation of pair of homologous chromosomes occur and they migrate to the opposite ends of the cell.
5. Telophase I:
In the final stage of meiosis I, chromosomes become diffuse and reformation of nuclear membrane occurs.
Here, cells are finally divided to form two new cells, followed by Meiosis II. The Haploid cells (newly formed) consist of one copy of each chromosome.
B. Meiosis II:
Two chromatids are formed by separating each chromosome in Meiosis II.
Note: Meiosis generates Genetic diversity.
To know more about the different Stages of Mitosis, click here.