Mutation - a random unpredictable change in a DNA molecule
Gene Mutation are changes in the sequence of nucleotides in the DNA that make up a gene. The different types of mutations are:-
- Substitution - this is where one base pair is substituted for another. This often has no effect because the DNA code is degenerate which mean each amino acid is coded or more than one triplet
- Deletion - loss of a base pair from the DNA molecule. Will cause a big difference because bases read as triplet. So if one goes missing then the entire sequence is read differently.
- Insertion - addition of a new base pair in the DNA
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Chromosome mutations are changes in the structure or number of chromosomes in a cell.
This occurs in meiosis I when paired chromosomes line up at metaphase and are pulled apart in anaphase
Number - chromosomes are not shared equally between daughter cells
- aneuploidy - one less chromosome or one extra chromosome
- polyploidy - one or more extra whole sets of chromosome
Structure
- Deletion - loss of a section of chromosome
- Duplication - doubling of a set of chromosome
- Translocation - part of a chromosome transfers to another
- Inversion - a section of a chromosome is inverted
