The origin of new alleles at a gene locus is the result of A - VCE - SSCE Biology - Question 8 - 2002 - Paper 1

The origin of new alleles at a gene locus primarily results from mutation. Mutations are changes in the DNA sequence that occur randomly but can lead to the introduction of new alleles into a population. Unlike migration, which involves the movement of individuals and their alleles between populations, or independent assortment and recombination, which involve the rearrangement of existing alleles during reproduction, mutations create entirely new genetic variants. Thus, the answer to the question is that new alleles arise due to mutation.