The difference between anaphase I and anaphase II lies in the timing of their occurrence during meiosis and the number of chromosomes present in the daughter cells. In anaphase I, homologous chromosomes separate, resulting in haploid daughter cells with duplicated chromosomes, while in anaphase II, sister chromatids separate, producing haploid daughter cells with unduplicated chromosomes.
In this article, we will cover the major difference between Anaphase I and Anaphase II.
Table of Content
What is Anaphase?
Anaphase is the third phase of mitosis, by which parent cells produce two identical daughter cells from their nucleus. Anaphase is a stage of cell division where sister chromatids or homologous chromosomes separate and move to opposite poles of the cell. This process ensures that each daughter cell receives the correct number of chromosomes during cell division. Before anaphase starts, the sister chromatids are positioned on the metaphase plate with their equator towards the cell.
Also Read: Overview on Anaphase
What is Anaphase I?
Anaphase I is a subphase of meiosis I. The process of meiosis begins with the first stage of prophase and then metaphase I, in this stage the homologous pairs of chromosomes align on each side of the equatorial plate ( this is also referred to as metaphase plate) and their centromeres attach with the spindle fibers coming from either pole of the cell. Once this chromosome arrangement is completed then the anaphase I phase begins.
The paired homologous chromosomes would start to separate (into haploid sets) from each other and move toward the opposite poles as the kinetochore microtubules shrink. This stage starts as soon as homologous chromosomes begin separating and ends when the chromosomes reach opposite poles
What is Anaphase II?
Anaphase II is a subphase of meiosis II. The process of meiosis II begins with the first stage of prophase and then metaphase II, which is the phase wherein the chromosomes are at the equatorial plane and spindle fibers are attached to the kinetochores. which is moved by 90º relative to anaphase 1.
The Anaphase II phase begins when sister chromatids (referred to as a daughter chromosome) Further contraction of the kinetochore microtubules pull each daughter chromosome separate and begin to proceed towards the opposite Poles. The shrinking of the kinetochore microtubules causes separation and movement.
Difference Between Anaphase I and Anaphase II
The difference between anaphase I and anaphase II is given below in tabular form:
Feature | Anaphase I | Anaphase II |
| Meiosis Phase | Anaphase 1 occurs during the meiosis 1 process of cell division. | Anaphase 1 occurs during the meiosis 1 process of cell division. |
| Separation During the Phases | In this phase, homologous chromosomes are separated and move toward the opposite Poles. | In this phase, sister chromosomes are separated and move toward the opposite Poles. |
| Haploid vs Diploid | This phase consists of two sets of chromosomes, one from each parent taking place in diploid cells. | This phase consists of a single set of chromosomes the haploid cell, |
| Metaphase Plate | in this stage, the homologous pairs of chromosomes align on each side of the equatorial plate | is that phase wherein the chromosomes are at the equatorial plane which is moved at 90º |
| Division of centromere | The centromere does not divide in this phase. | In this step, the sister chromatids are separated by the division of the centromere. |
| Spindle Fibers | Spindle fibers attach to homologous chromosomes | Spindle fibers attach to individual chromatids |
Similarities Between Anaphase I and Anaphase II
Despite the difference, there are some similarities between Anaphase I and Anaphase II as well which are given below:
- Both Anaphase I and Anaphase II are part of the cell division process in meiosis.
- Both Phases' spindle fibers pull chromosomes toward the ends of the cells.
- Spindle fibers shrink in both phases.
Conclusion - Difference Between Anaphase I and Anaphase II
In conclusion, Anaphase is a crucial phase of mitosis and meiosis where chromosomes separate and move to opposite poles of the cell, ensuring accurate chromosome distribution in daughter cells. Anaphase I and Anaphase II occur during different stages of meiosis, with Anaphase I separating homologous chromosomes and Anaphase II separating sister chromatids. While there are differences in chromosome count and spindle fiber attachment, both phases play vital roles in cell division, emphasizing accurate chromosome segregation
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