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# Variation and mutation

Where variants come from, how damage is repaired and how a variant is classified.

7 pages

- [**Types of mutations** A mutation is a change in the DNA sequence; depending on where and how it happens it may do…](https://durgical.com/en/biochemistry/topics/types-of-mutations/)
- [**Where new mutations come from: de novo variants, rates and parental age** Every child carries a few dozen DNA changes neither parent had; how often, where and in which…](https://durgical.com/en/biochemistry/topics/where-new-mutations-come-from-de-novo-variants-rates-and-parental-age/)
- [**DNA polymorphisms, linkage and DNA fingerprinting** Small DNA differences between people are inherited markers: they follow genes through families…](https://durgical.com/en/biochemistry/topics/dna-polymorphisms-linkage-and-dna-fingerprinting/)
- [**Interpreting genetic variants: classes, evidence and databases** Finding a DNA change is the easy part; deciding whether it causes disease uses population data…](https://durgical.com/en/biochemistry/topics/interpreting-genetic-variants-classes-evidence-and-databases/)
- [**DNA repair** Cells fix thousands of DNA lesions every day with several repair systems; when one fails, cancer…](https://durgical.com/en/biochemistry/topics/dna-repair/)
- [**Trinucleotide repeat expansion disorders** Some diseases come from a three-base unit repeated too many times; the repeat tends to grow from…](https://durgical.com/en/biochemistry/topics/trinucleotide-repeat-expansion-disorders/)
- [**Mutagens and the Ames test** Mutagens are agents that change DNA; the Ames test screens chemicals for this by checking…](https://durgical.com/en/biochemistry/topics/mutagens-and-the-ames-test/)

[← Medical genetics](https://durgical.com/en/genetics/)

This section is an index: it gathers pages from Biochemistry, Pathology, Embryology and other sections without repeating them. Educational content; it does not replace a geneticist's assessment or genetic counselling.

Representative model, for educational purposes only.

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Source: https://durgical.com/en/genetics/variation/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/genetics/variation/