The end of Pachytene terminates the process of recombination between homologous chromosomes but leaves the chromosomes linked with each other at the location of crossing over.ĭIPLOTENE: Disintegration of the synaptonemal complex Marks the beginning of the Diplotene stage. It is an enzyme-mediated process where the recombinase enzyme functions. In crossing over, the exchange of genetic materials between the two homologous chromosomes takes place. Recombination nodules are the locations where, between the nonsister chromatids of the homologous chromosomes, crossing over takes place. One of the characteristic features of this stage is the appearance of recombination nodules. PACHYTENE: In the Pachytene stage, the distinction and clear appearance of the four chromatids of each of the bivalent chromosomes as tetrads is seen. These complexes are better visible from the next steps. The complex produced by the pair of homologous chromosomes that have undergone synapsis is termed a bivalent or a tetrad. Formation of the synaptonemal complex also accompanies the process of synapsis, which becomes evident in the electron micrographs of this stage. These paired chromosomes are eventually called homologous chromosomes. Synapsis is the process of association or pairing of chromosomes. During this process, the process of synapsis occurs. ZYGOTENE: Zygotene is the second step in the Prophase of Meiosis I which follows Leptotene. During Leptotene, the condensation of chromosomes continues throughout this stage. LEPTOTENE: During this step, the chromosomes start to be seen under the light microscope. This single substep of Prophase is further subdivided into 5 stages, namely - Leptotene, Zygotene, Pachytene Diplotene, and Diakinesis. The Prophase of Meiosis is quite long and more complex than the Prophase of Mitosis. This is the first step in the process of Meiosis cell division. Broadly, the meiosis cell division occurs in two steps - Meiosis I and Meiosis II, which again have their substeps.
Four haploid cells are formed at the end of the process of meiosis. They may also get separated into individual chromosomes when necessary.Īfter this, finally the process of meiosis, the reductional cell division occurs. The centromere connects both of them in the chromosome at the center for storage. After this, each chromosome has two sister chromatids which are the cloned DNA after replication. This is important before the starting of the reduction process.
PROPHASE METAPHASE ANAPHASE AND TELOPHASE FULL
Hence, there are now 4 copies of each of the genes, located in two full sets of DNA and each of those sets have two alleles. Before the initiation of the process of meiosis, a very important event has to occur, which is the replication or duplication of the normal diploid DNA or chromosomes.
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