Researchers study a population of freshwater prawns. Earlier samples contained alleles with the DNA base sequences ACGTTA and ACGCTA. A later sample contains a third allele with the sequence ACGGTA.
Which event represents the creation of the ACGGTA allele?
During fertilisation, gametes carrying ACGTTA and ACGCTA joined to form an offspring.
In a cell that produces offspring, one DNA base in ACGTTA changed, producing ACGGTA.
An offspring inherited ACGGTA from a parent that already carried this allele.
During meiosis, ACGTTA was placed into a gamete that later formed an offspring.
122 exam-style questions on OCR GCSE Biology 5.2 Natural selection and evolution, covering 5.2.1 Genetic variation within a population, 5.2.2 Developments in classification systems, 5.2.3 How evolution occurs through natural selection, 5.2.4 Evolution as change over time, 5.2.5 Evidence for evolution, and 5.2.6 Darwin and Wallace. Each one has a worked solution and a mark scheme showing where the marks go.