Practice question

Ultimate source of all novel genetic variation is creation of new allele sequences not previously present in population. Recombination, independent assortment, gene conversion, and migration rearrange or redistribute existing variants but do not generate new base sequences de novo. Mutation through DNA replication errors, spontaneous chemical alterations like deamination and depurination, and induced lesions produces entirely new nucleotides, codons, and regulatory motifs. These nascent alleles provide raw material upon which natural selection, drift, and gene flow operate during evolution. This principle illustrates essential molecular mechanisms governing replication fidelity and mutation fixation relevant for exam interpretation.