Question

A plant has two alleles for color. The red allele is recessive and is represented by q. The purple allele is dominant and is represented by p. If 30 of 100 organisms are red, what is q?. p^2+2pq+q^2=1. A. 0.55. B. 0.30. C. 0.49. D. 0.70

Answer 1

If 30/100 organisms are red (have a red phenotype), this only occurs if it has the qq allele, which has probability q². This implies that q² = 0.3, and q = √0.3 = 0.55.
The rest of the possible genotypes: pp, pq, and qp, would all result in a purple appearance, since p is the dominant allele.