In pea plants, seed texture is determined by a single gene with two alleles. The allele for round seeds is dominant over the allele for wrinkled seeds.
A researcher crossed homozygous round-seeded pea plants with homozygous wrinkled-seeded pea plants. All of the offspring (F1 generation) had round seeds.
Use a genetic diagram to show the parent genotypes, the gametes formed, and the genotypes of the F1 offspring. Use RRR to represent the allele for round seeds and rrr to represent the allele for wrinkled seeds.
The researcher then ensured that the F1 offspring plants could only self-pollinate. The seeds produced grew to give F2 plants with a 3:13 : 13:1 phenotypic ratio of round to wrinkled seeds. Suggest how the researcher could ensure that these pea plants self-pollinated and were not cross-pollinated by other plants.
Give the genotypes of the F2 offspring obtained from the self-pollinated F1 plants.
What is meant by the term recessive allele?
Some phenotypes are controlled by codominant alleles. What is meant by the term codominant alleles?
