Question

which statement describes the mechanism by which new alleles are formed?
○ random segregation of homologous chromosomes during meiosis leads to new allele formation.
○ all of the possible alleles already exist, and new alleles cannot be formed.
○ mating individuals with differing phenotypes leads to offspring with new alleles.
○ natural selection, occuring over many generations, leads to the formation of new alleles.
○ mutations can occur within existing genes, which brings about new allele variations.

Explanation:

Mutations are the source of new alleles. They can alter the DNA sequence within a gene, creating new allele variants. Random segregation during meiosis (first option) shuffles existing alleles, it doesn't create new ones. The second option is incorrect as new alleles can form. Mating (third option) combines existing alleles. Natural selection (fourth option) acts on existing variation (alleles), it doesn't create new alleles. Only mutations (fifth option) can form new alleles.

Answer:

Mutations can occur within existing genes, which brings about new allele variations.