3.1.10 (HL)—Sources of genetic diversity

Mutation can create a new allele; sexual reproduction reshuffles existing alleles into new combinations.

Recombination and fertilization increase variation among offspring without inventing a new DNA variant. Selection then changes which variants contribute to future generations.

A copying error creates allele A2; crossing parents with A1 and B1 produces a new A1B1 combination without a new allele.

Mutation; recombination only rearranges variants already present.

‘More variation’ does not specify whether the change is a new allele or a new combination.