During Telophase, the spindle fibres break down and disappear, allowing the nuclear membrane to re-appear around the two sets of 46 haploid chromosomes on opposite poles of the cell. The nucleolus also reforms. The chromosomes become uncoiled (spaghetti-like).
The process of cytokinesis occurs as the cell is compressed from the middle and divided into two; two identical daughter cells that each contain 46 haploid chromosomes form. These daughter cells also contain the same genetic material as the original parent cell. Once this process is over, the organelles begin to reform as well.
Meiosis in Locust Testis Squash Cells
The chromosomes in the locust testis cells undergo replication in the S phase of Interphase. The 46 single stranded (46 haploid) chromosomes duplicate and form 92 single stranded (96 haploid) chromosomes which are in the state of chromatin. They do not form diploid chromosomes as they are not yet condensed. The nuclear membrane still exists and protects the chromosomes.
In Prophase I, the 92 single stranded chromosomes become condensed and form 46 diploid chromosomes. The centriole divides into two daughter centrioles and they each move to opposite poles of the cell. The nuclear membrane disappears along with the rest of the organelles. A tetrad is formed when two homologous diploid chromosomes come together. Every tetrad consists of two homologs, each containing sister chromatids of the maternal and paternal DNA, in total there are four chromatids. These homologous pairs go through a synapsis process where they join and intertwine; they are expected to exchange alleles (pieces of corresponding genes on the DNA) and form new genetic combinations in chromosomes; however, this process called crossing over may not always occur.
During Metaphase I, once the nuclear membrane completely disappears and allows the spindle fibres which grow from centrioles to hook on to the centromere that holds the homologous chromosome pairs together and align the 23 tetrads at the equator of the cell. Random assortment will lead to genetic variation as the diploid chromosome pairs align randomly.
In Anaphase I, the pair of homologous diploid chromosomes are separated from each other and pulled to the opposite poles of the cell by the shortening of spindle fibres. Sister chromatids remain, only the maternal and paternal diploid chromosomes are pulled to opposite poles.
During Telophase I, the nuclear membrane re-forms around the two sets of 23 diploid chromosomes which are now placed in opposite poles of the cell. The chromosomes become string-like again and the cell divides into two through the cytokinesis process, forming two daughter cells of 23 double-stranded chromosomes.
The two daughter cells enter Meiosis II. The first phase is prophase II, where centrioles duplicate and begin to form spindle fibres, also moving to opposite poles of the cell. The 23 diploid chromosomes in each of the two cells become condensed again.
The nuclear membrane begins to break down. In Metaphase II, all the 23 diploid chromosomes align, unpaired, on the equator of the cell with the help of spindle fibres manoeuvring them. The spindle fibres grow and attach to the centromere (that holds the sister chromatids) from both sides of the cell in order to manoeuvre the chromosomes into aligning position.
In Anaphase II, this time the centromeres of each diploid chromosome are separated and the sister chromatids are pulled to opposite poles by the shortening of the spindle fibres. This results in 23 haploid chromosomes on each side of the cell. Telophase II is when the nuclear membrane re-appears around the two sets of 23 haploid chromosomes in the two daughter cells. The haploid chromosomes become un-coiled and spaghetti-like again. The spindle fibres break down and disappear. Cytokinesis occurs to divide both the cells with each containing 23 haploid chromosomes. This results in four daughter cells, each containing 23 haploid chromosomes.
The four daughter cells, each containing 23 haploid chromosomes are not genetically identical to each other due to the recombination between chromosome segments of the original parent cell, which is crossing over. Random assortment during the lining up of the 23 tetrads in Metaphase I has also caused genetic variation in the daughter cells produced.