Suppose that a human zygote begins life with 1500 telomere r

Suppose that a human zygote begins life with 1500 telomere repeats. Most somatic cells lose telomeres at every mitotic cell division. Further suppose that a cell begins to lose essential genes (non-telomere sequences) from its ends after 50 cell generations. How many cells are produced from one precursor cell after 50 cell generations? On average, how many telomeres are lost at each mitosis? Explain why telomeres are lost in the context of question 1.

Solution

Each Mitotic Division results in 2 daughter cells. Consider the following sequence:

From a single precursor cell, 1 mitotic division results in 2 daughter cells (1 cell generation)

These 2 daughter cells undergo mitotic division to produce 4 daughter cells (2 cell generation)

These 4 daughter cells undergo mitotic division to produce 8 daughter cells (3 cell generation) and so on...

Therefore, the no. of cells produced after \'n\' cell generations can be calculated as 2ⁿ, where \'n\' is the number of cell generations.

Therefore, after 50 cell generations, the number of cells produced from a single precursor cell = 2⁵⁰ =

1 125 899 906 842 624 cells.

Now, to produce 50 cell generations, 1 125 899 906 842 624 times mitosis occurs. Since there are 1500 telomere repeats which are lost over 1 125 899 906 842 624, therefore at each mitosis 1500/1 125 899 906 842 624 telomeres are lost, which is approximately 1500/125900000000000 = 2 X 10^-5 telomere repeats.

Thank you!

1 125 899 906 842 624 cells. Now, to produce 50 cell generations, 1 125 899 906 842 624 times mitosis occurs. Since there are 1500 telomere repeats which are lost over 1 125 899 906 842 624, therefore at each mitosis 1500/1 125 899 906 842 624 telomeres are lost, which is approximately 1500/125900000000000 = 2 X 10-5 telomere repeats. Thank you!