in addition to the above a labelled diagram is also required to show the product cells derived from this cell at the telophase 2 stage of meiosis.there is no crossng over.what differences would there be in the product cells at telophase 2 of meiosis if there had been one crossing over at a position halfway betwen the huntington desease gene and the centrome.
To create a labelled diagram to show the product cells at telophase 2 of meiosis, it is necessary to understand the process of meiosis and the effect of crossing over.
1. Normal Meiosis without Crossing Over:
In the absence of crossing over, the homologous chromosomes separate during meiosis I, leading to two daughter cells. These daughter cells undergo another round of cell division in meiosis II, resulting in a total of four haploid cells (gametes). Each of these cells has a random combination of chromosomes from the parent cell. The Huntington disease gene is located somewhere on one of the chromosomes.
To draw the labelled diagram, start by drawing a parent cell with its chromosomes and label the Huntington disease gene in the appropriate position. Then, draw the two daughter cells resulting from meiosis I. Lastly, draw another round of cell division, resulting in four haploid gametes (product cells), ensuring that each gamete has a random combination of chromosomes.
2. Meiosis with Crossing Over:
If crossing over occurs at a position halfway between the Huntington disease gene and the centromere, it will affect the final products of meiosis II.
Crossing over is the exchange of genetic material between homologous chromosomes that occurs during prophase I of meiosis. This process leads to a recombination of genes in the offspring's chromosomes.
In this case, when crossing over occurs between the Huntington disease gene and the centromere, it will result in the exchange of genetic material between the chromatids.
To depict this scenario in the labelled diagram, start by drawing a similar parent cell with its chromosomes and label the Huntington disease gene and centromere. Then, illustrate a crossing over event between the Huntington disease gene and the centromere by showing a break and rejoining between chromatids of corresponding homologous chromosomes in prophase I.
After that, proceed with meiosis I and draw the resulting daughter cells. In meiosis II, each of these daughter cells will now have a different combination of alleles for the Huntington disease gene due to the crossing over event. Label the new combinations accordingly.
Finally, complete the process by drawing the four haploid gametes (product cells) resulting from the second round of cell division, which will now have different combinations of chromosomes as a result of crossing over.
By creating this labelled diagram, you will be able to visually represent the product cells at telophase 2 of meiosis, both without and with crossing over.