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Meiosis

Meiosis only occurs in the and , producing gametes (sperm and egg cells).

This is known as reduction division.

One cell produces four gametes, in two divisions.

Human sex cells contain one from each of the 23 pairs.

Meiosis human reproduction

The four gametes produced in meiosis are genetically different.

The process of leads to all gametes being different.

Independent assortment and the random nature of fertilisation lead to variation in living organisms – no two organisms are the same (apart from identical twins).

Meiosis

During fertilisation the haploid nucleus of a sperm cell and the haploid nucleus of an egg cell fuse together to form a diploid zygote.

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