Q.Explain why meiosis and gametogenesis are always interlinked?

Gametogenesis is the process of formation of male and female gametes, and meiosis is a special type of cell division in which the chromosome number is reduced to half (from diploid, 2n, to haploid, n). These two processes are always interlinked for the following reason:

• The body (somatic) cells of a sexually reproducing organism are typically diploid (2n) — they carry two sets of chromosomes, one inherited from each parent.
• Gametes, however, must be haploid (n) — carrying only a single set of chromosomes — because during fertilisation, a male gamete (n) fuses with a female gamete (n) to form a zygote (2n).
• If gametes were diploid (produced by ordinary mitotic division instead of meiosis), then fertilisation would produce a zygote with double the normal chromosome number (4n), and this number would keep doubling with every subsequent generation — a situation that is biologically unsustainable and does not occur in nature.
• Meiosis is the only type of cell division that reduces the chromosome number by half (through one round of DNA replication followed by two successive divisions), converting diploid germ cells into haploid gametes.
• Therefore, in order to maintain a constant chromosome number for a species across generations, every act of gametogenesis must involve meiosis at some stage. …

Reason from the requirement that fertilisation needs haploid + haploid = diploid; since somatic/germ cells start diploid, only a reductional division (meiosis) can create the ne …

• Saying gametes are 'formed by meiosis' without explaining WHY that is necessary (i.e., without the haploid-diploid chromosome-number argument).
• Confusing mitosis and meiosis, or suggesting gametes could be produced by mitosis. …