At puberty, these cells begin undergoing , which is a type of cell division that decreases the number of chromosomes and varies the genes found in the gametes.

On the onset of puberty the gametogonium (stem cells) undergo meiosis, which is a cell division that reduces the number of chromosomes by half and varies the genes in the gamates.

Explanation:

Gametogenesis is the process of production of gametes, by the process of meiosis, on the onset of puberty.

During the process of meiosis, two cell divisions occur, which separate the paired chromosomes present in nucleus, followed by the separation of the chromatids. This results in the production of gametes containing half of the number of chromosomes as compared to the gametogonium, stem cells; thus varying the genes in the gamates.

Gametogenesis is known as oogenesis, in females and spermatogenesis, in males.  

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