Color in poison dart frogs is controlled by a single gene with multiple alleles. A blue poison dart frog that is heterozygous fo
r the blue allele (Cb) and red allele (Cr) is crossed to a yellow poison dart frog that is heterozygous for the orange (Co) and yellow (Cy) alleles. Their progeny are 1/2 blue, 1/4 orange, and 1/4 yellow. Determine the order of dominance for the alleles. (Order of dominance is indicated as: A > B > C > D such that A is dominant over all alleles, B is dominant over C and D, C is dominant only to D, and D is recessive to all alleles.)
First of al we need to do the Punnett square. As a result we get the genotypes:
CyCb
CyCr
CoCb
CoCr
Because there are no red frogs, red is the least dominant as it isn't expressed in any genotype.
Half of the progeny are blue and half of the possible genotypes contain the blue allele meaning that blue is expressed in all genotypes. This means that blue is the most dominant.
The only alleles left are yellow and orange. We can deduce that yellow is more dominant than orange because one of the parent frogs is yellow and contains the genes for yellow and orange.
As a result blue is the most dominant, yellow is the second most dominant, orange is the third most dominant and red is the least dominant.
