Explain how mutations in an organism's DNA can lead to variation in a population of the same species.

Edexcel GCSE Biology (1BI0) — 3.5 Variation and mutation · Explain · 4 marks · View as Markdown

Written & reviewed by James Millett — Biology (Imperial College London), PGCE Science (University of Cambridge).

Scientists studying a population of Arctic foxes found that, over many generations, some individuals had fur colours that differed from the rest of the population. These differences were passed on to offspring.

Model answer (4 marks)

A mutation is a random change in the base sequence of DNA.
A mutation can produce a new allele of a gene.
Different alleles can lead to different proteins being produced, resulting in a different phenotype.
Mutations contribute to genetic variation because they introduce new alleles into the population, which can be inherited by offspring.

Examiner tips

  • Use the exact wording from the mark scheme, e.g. "mutation", "allele", "phenotype". Show the causal chain: mutation → new allele → new protein → new phenotype. Keep the answer to four short, clear points.
  • common_mistakes
  • :
  • Using vague terms such as "change" instead of "mutation". Failing to mention that mutations are random. Not linking the new allele to a change in protein and phenotype.

Mark scheme (4 marks)

  1. A mutation is a random change in the base sequence of DNA
  2. A mutation can produce a new allele of a gene
  3. Different alleles can lead to different proteins being produced, resulting in a different phenotype
  4. Mutations contribute to genetic variation because they introduce new alleles into the population, which can be inherited by offspring

Key terms in this question

mutation

Related

More Variation and mutation questions

▶ Try answering this question with AI marking (free) →