Question

Why is it that mitosis is used to produce new body cells instead of meiosis?

Answer 1

Mitosis as we all know as equational division which means that the ploidy of the cell remains maintained even after the cell division takes place. In contrast meiosis is a process of reductional division where in the ploidy of the cell becomes halved after the division takes place. Meiosis generally takes place only in the gamete cells (sperm and egg cell) and rest all of the body cells divide by the process of Mitosis.

Keeping in mind the fact that the cells have 46 chromosomes and this is the ploidy (2n=46) which needs to be maintained in all the cells of the body uniformly. Therefore all the cells of the body divide by the process of Mitosis where in the cell ploidy remains same even after one cell divides and give rise to two daughter cells which can further divide similarly and the process continues. Cell division does not take place by meiosis because then a cell with 46 chromosomes will give rise to four daughter cells with 23 chromosomes each, as the ploidy gets halved. Further such daughter cells if undergo meiosis to divide further would reduce the ploidy of the cells to another half and at a certain point the division would become finite. Also, eventually all the cells of the body will have different number of chromosomes which will lead to a huge genetic imbalance in complex organism like human beings where in each gene located on different chromosome pairs play an important role in maintaining the genetic balance in the body.

However the gamete cells like sperm and eggs cell undergo division by meiosis wherein its is necessarily reauired to reduce their ploidy into half (n=23) and eventually after fertilization when the male and female pronuclei fuse together, the ploidy get restored back to 2n=46 and thus same chromosomal number of the specie is maintained in the offspring as well.