BRAINCAKEChromosome Mutations
Chromosome mutations affect large sections of DNA or whole chromosomes, so they usually change many genes at once. They often happen when chromosomes break or are separated incorrectly during meiosis.
Changes in chromosome structure:
• deletion: a section of chromosome breaks off and is lost
• duplication: a section is repeated, so genes are present in extra copies
• inversion: a section breaks off, turns round through 180° and rejoins, so the gene order in that section is reversed
• translocation: a section breaks off one chromosome and joins a different, non-homologous chromosome
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Key terms in this lesson
- meiosis
- A type of nuclear division that produces four haploid daughter cells, each genetically different, from one diploid parent cell; it makes gametes.
- homologous chromosomes
- A pair of chromosomes, one from each parent, that are the same size and shape and carry the same genes at the same loci.
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