Types of large-scale mutation
There are several common types of large-scale mutations:
Gene duplication: a whole gene, or block of genes, is repeated on the chromosome. Gene duplications often result from unequal crossover during meiosis.
If the chromosomes do not line up correctly, the recombined sections will not be equivalent. This results in a loss of genes from one chromosome and a gain on the other.
- Gene deletion: loss of a whole gene or a block of genes. Gene deletions are also caused by unequal recombination during meiosis.
- Chromosomal translocation: the movement of genes from one chromosome to another non-homologous chromosome. Some cancers are a result of translocations.
- Chromosomal inversion: a section of genetic material is reversed on the chromosome. This is often unproblematic but can lead to reproductive problems.
- Non-disjunction: homologous chromosomes fail to separate during meiosis, resulting in either a gain or loss of a chromosome in the cell.
- Aneuploidy: errors in cell division can result in changes in the number of chromosomes.