Genetic Variation

What is Genetic Variation?

Differences in the genes carried by individuals of the same species. Sexual reproduction generates genetic variation because meiosis produces genetically different gametes and fertilisation combines them at random; asexual reproduction generates almost none, because the offspring are produced by mitosis from a single parent.

This definition is part of the Development of Organisms and Continuity of Life chapter in Cambridge O Level Biology.

Concepts related to Genetic Variation

• Natural Selection
• clone
• adaptation

Common mistakes with Genetic Variation

• “Asexual reproduction produces variation.” Why wrong The offspring come from one parent by mitosis, so they carry the same genes. Any variation you can see is environmental, not genetic. Say instead Asexual reproduction produces genetically identical offspring; there is very little genetic variation between them.
• “Self-pollination is asexual reproduction.” Why wrong Gametes are still made by meiosis and two haploid nuclei still fuse. That is sexual reproduction, regardless of where the pollen came from. Say instead Self-pollination is sexual reproduction with less genetic variation than cross-pollination.