Variation and mutation

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

7 pages

• Types of mutationsA mutation is a change in the DNA sequence; depending on where and how it happens it may do…
• Where new mutations come from: de novo variants, rates and parental ageEvery child carries a few dozen DNA changes neither parent had; how often, where and in which…
• DNA polymorphisms, linkage and DNA fingerprintingSmall DNA differences between people are inherited markers: they follow genes through families…
• Interpreting genetic variants: classes, evidence and databasesFinding a DNA change is the easy part; deciding whether it causes disease uses population data…
• DNA repairCells fix thousands of DNA lesions every day with several repair systems; when one fails, cancer…
• Trinucleotide repeat expansion disordersSome diseases come from a three-base unit repeated too many times; the repeat tends to grow from…
• Mutagens and the Ames testMutagens are agents that change DNA; the Ames test screens chemicals for this by checking…

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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.