Prophase occurs in both meiosis and mitosis but Prophase 1 (as a stage) only occurs in meiosis. Homologous chromosomes pair and link up, creating synapses during meiosis prophase 1, a process that only occurs during meiosis. Prophase one (Prophase I) and Prophase two (Prophase II). Homologous chromosomes come together to form pairs and appear as bivalentsįigure 1.Microtubule-organizing centers (e.g., centrosomes) begin to move towards opposite ends of the cell, produce and organize the spindleĬonversely, Prophase I is unique in such a way that….Breaking down of nuclear envelope and nucleolus.Condensation of genetic material (chromatin), referred to as chromosomes.Nevertheless, all three are highlighted by the following features: These distinct stages are, therefore, not observed in Prophase II and in Mitotic prophase.

These five stages of Prophase I make up the first stage of the first meiotic division. (The condensed chromatins are referred to as chromosomes.) However, Prophase I differs from Prophase of mitosis and Prophase II of meiosis II in having these stages - leptotene, zygotene, pachytene, diplotene, and diakinesis. In particular, the chromatin (a combination of DNA and proteins) of the parent cell, is condensed during prophase. Now, what is prophase? Is it the same as Prophase 1? How about Prophase 2? Prophase is that phase of mitosis and meiosis where the duplicated genetic material undergoes condensation in the nucleus. One chromosome from each parent makes up the bivalent’s two chromosomes and four chromatids. These are visible under a microscope because of chromosomal condensation. The paired homologous chromosomes in synapses are known as bivalents, and it is now clear that genetic recombination is what causes chiasmata to occur. Each of these phases is designated as I or II depending on where it occurs, i.e. These are prophase, metaphase, anaphase, and telophase. There are two successive nuclear divisions: meiosis I and meiosis II.Įach of them has four major phases. Meiosis is a specialized form of cell division that ultimately gives rise to non-identical haploid gametes (or haploid sex cells).

Prophase I precedes metaphase I, a stage that features homologous chromosomes aligning along a single plane in the center of the cell.īefore we move on and become acquainted with the various substages of prophase I, let us first understand some basic concepts.

This stage then ends with the disintegration of the nucleolus and the nuclear membrane. Thus, this stage is important to increase genetic variation. Prophase I highlights the exchange of DNA between paired chromosomes via a process called homologous recombination and the crossover at chiasmata (singular: chiasma) between non-sister chromatids.

This stage is characterized by five stages, namely leptotene, zygotene, pachytene, diplotene, and diakinesis, that make it up. Prophase I is the first stage of meiosis I. Let’s read on to find answers to what is prophase 1, what happens in prophase 1, and what is the importance of prophase 1. This includes prophase, which consists of prophase 1 (for meiosis 1) and prophase 2 (for meiosis 2). The stages of meiosis 1 (or meiosis I) are named after the first process and the same occurs for meiosis 2 ( meiosis II).

During prophase 1 of meiosis