Mutations can arise spontaneously during DNA replication and include base deletion and base substitution
During DNA replication, copying errors can occur by accident. These errors — called mutations — change the sequence of bases in the DNA, and they happen without any external cause.
Real World
BRCA1 gene mutations, which significantly increase breast cancer risk, frequently arise from base deletions or substitutions that occur spontaneously during DNA replication in rapidly dividing breast tissue cells.
Exam Focus
Clearly distinguish effects: base substitution changes one codon only; base deletion causes a frameshift altering all downstream codons — this distinction is frequently tested.
Evaluation Scaffold
A four-step framework for high-quality evaluation. Use this for 'assess', 'evaluate', and 'to what extent' questions.
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