Why does each germ cell carry only one copy of each gene? What would happen if germ cells had the same number…

Question

Why does each germ cell carry only one copy of each gene? What would happen if germ cells had the same number of gene copies as ordinary body cells?

Accepted Answer

## Model Answer Germ cells are formed by **meiosis**, a special cell division that halves the chromosome number. So each germ cell carries only one copy (half set) of each gene. If germ cells had the same number of gene copies as body cells, then after fertilisation (fusion of two germ cells), the new individual would have **twice** the DNA of the previous generation. This would keep doubling each generation, disrupting the control of the cellular apparatus by DNA. *Source: Chapter 7, Section 7.3.1 — Why the Sexual Mode of Reproduction?* --- ## Explanation - The key term to use is **meiosis** — examiners expect it. - Two points carry 1 mark each: (1) why germ cells have half the DNA, and (2) the consequence if they didn't (doubling of DNA each generation). - Avoid vague answers like "to maintain balance" — be specific: *fusion of two germ cells would double the DNA content each generation*.

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