Question

What does diakinesis of prophase-I indicate?

Answer 1

Meiosis 1:

Meiosis 1 splits a pair of homologous chromosomes and converts a diploid cell to a haploid cell.

The following phases help explain the various stages of meiosis 1:

1. Prophase 1: Prophase I in meiosis is the most complicated prophase repetition that occurs in both plant and animal cells.
2. Metaphase 1: A kind of cell division that produces gametes, cells with half the typical number of chromosomes.
3. Anaphase1: After prophase I, the third stage of the first meiotic division shows the separation of paired homologous chromosomes towards opposing ends of the cell.
4. Telophase: Between anaphase and interphase, the last phase of cell division is in which the chromatids or chromosomes travel to opposing ends of the cell and two nuclei develop.

Prophase 1:

1. Prophase 1 is the longest phase of meiosis, during which three major events occur.
2. The first part is the condensation of chromatin into chromosomes, the second is physical contact between homologous chromosomes, and the third is genetic information transfer between synapsed chromosomes.
3. All of these features take place in five sub-phases.

The five sub-phases of prophase 1 are as follows:

1. Leptotene: It is a meiotic prophase stage just before synapsis in which the chromosomes appear as fine distinct threads.
2. Zygotene: It is a stage of meiotic prophase that occurs soon after leptotene and during which homologous chromosomal synapsis occurs.
3. Pachytene: Crossing over occurs during this period to exchange chromosomal material between maternal and paternal homologous chromosomes.
4. Diplotene: It is a meiotic prophase stage that follows pachytene and is characterised by the separation of paired homologous chromosomes and the appearance of chiasmata.
5. Diakinesis: The last stage of prophase I of meiosis I, during which the chromosomes consolidate and the nucleolus fragments and nuclear envelope scatter.

Diakinesis of prophase-I:

1. Diakinesis is the last step of prophase-1 meiosis (a five-stage process).
2. Diakinesis is distinguished by chiasmata terminalization.
3. Bivalents are distributed equally in the nucleus at this stage.
4. The nuclear membrane degrades and the nucleolus vanishes.
5. Chiasma progresses towards the finish, a process known as terminalization.
6. Chromatids are exclusively connected at the terminal chiasmata and enter metaphase.
7. Recondensation of chromosomes occurs.
8. Tetrads migrate to the equatorial metaphase plate, and spindle development begins.
9. Diakinesis represents the shift to metaphase.