Difference Between Anaphase I and Anaphase II

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.

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

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

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.

The difference between anaphase I and anaphase II is given below in tabular form:

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.

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

Also Read:

• Diagram of Mitosis
• Diagram of Meiosis
• What is Karyokinesis?
• What is Cytokinesis? 
• Diagram of Cell Cycle
• Meiosis ll : Equational Cell Division
• Cell Cycle – Definition, Phases of Cell Cycle

What is the Major Difference Between Anaphase I and Anaphase II?

Anaphase I separates homologous chromosomes, while Anaphase II separates sister chromatids.

What is the Difference Between Anaphase A and Anaphase B?

Anaphase A involves the movement of chromosomes towards the poles, while Anaphase B involves the separation of spindle poles.

What is the Main Difference Between Metaphase I and Metaphase II?

Metaphase I aligns homologous chromosomes at the metaphase plate, while Metaphase II aligns sister chromatids.

What are Two Important Facts About Anaphase 1?

Anaphase 1 is the third phase of meiosis 1, throughout the phase of anaphase 1, one pair of the homologous chromosome, which forms a bivalent, is moved towards the opposite ends of the cell with the help of spindle fibers attached to the centromere through kinetochores.

Why is the Anaphase Phase Different?

Anaphase is a very important phase of meiosis 1 of cell division. It ensures that homologous chromosomes, or sister chromatids, separate into two equal sets. This separation of chromosomes is referred to as disjunction. Each set of chromosomes will become part of a new cell.

How Many Chromosomes are in Anaphase 1?

In anaphase I, the attachment of the spindle fibers is complete. The homologous chromosomes are pulled apart and move toward opposite Poles. At this point in which reduction takes place with 23 chromosomes moving toward each pole.