Mutations in Chromosome Number
- Mutations can occur at different levels
- Non-disjunction occurs when chromosomes fail to separate during meiosis
- This occurs spontaneously
- The gametes may end up with one extra copy of a particular chromosome or no copies of a particular chromosome
- These gametes will have a different number of chromosomes compared to the normal haploid number
- If the abnormal gametes take part in fertilization, then a chromosome mutation occurs as the diploid cell will have the incorrect number of chromosomes
- Chromosome mutations involve a change in the number of chromosomes
- An example of chromosome mutation is Down’s syndrome: Individuals with this syndrome have a total of 47 chromosomes in their genome as they have three copies of chromosome 21