Occasional errors may occur during DNA replication.
In biology, a mutation is a change in the genetic material. This means changes to the DNA or to the chromosomes which carry the DNA. These changes are heritable (can be passed on to the next generation) unless they have lethal effects.
Mutations can happen for several reasons. It can happen because of errors when meiosis produces the gametes (eggs & sperms). Damage by radiation, or by certain chemicals may cause mutations. Mutations occur at random.
Also, by derivation, an individual carrying the mutation may be called a mutant or a mutation. So is the trait (character) most obviously affected by the mutation.
Types of mutation
duplication causes different lengths at a single locus (allele
). Shows variation in one gene in six individuals
When DNA is copied mistakes are sometimes made – these are called mutations. There are four main types of mutations:
- Deletion, where one or more DNA bases are left out.
- Insertion, where one or more extra base is put in.
- Substitution, where one or more bases are changed for another base in the sequence.
- Duplication, where whole genes are copied.
These terms are explained in the third diagram.
- Deletion: a piece of chromosome is lost, together with any genes which may be on it.
- Duplication: part of a chromosome is repeated
- Inversion: part of a chromosome is reversed end to end
- Insertion: a smaller chromosome is added into a longer chromosome
- Translocation: part of a chromosome gets moved onto another chromosome
srpskohrvatski / српскохрватски: Mutacija