You are an aspiring botanist and decide to study some orchid genetics. Knowing that the pink color phenotype is an incompletely dominant phenotype, you decide to study it further. You discover that when you cross two pink orchids, you only ever obtain a phenotypic ratio of 1/3 white orchids to 2/3 pink orchids. How might you explain this phenomenon

You are an aspiring botanist and decide to study some orchid genetics. Knowing that the pink color phenotype is an incompletely dominant phenotype, you decide to study it further. You discover that when you cross two pink orchids, you only ever obtain a phenotypic ratio of 1/3 white orchids to 2/3 pink orchids. How might you explain this phenomenon

A)The dominant color allele produces a lethal phenotype when one copy is present. B)The recessive color allele produces a lethal phenotype when two copies are present. C)The dominant color allele produces a lethal phenotype when two copies are present. D)The recessive color allele produces a lethal phenotype when one copy is present

C)The dominant color allele produces a lethal phenotype when two copies are present.

Explanation:

Let's suppose that allele R gives a pink phenotype in the heterozygous condition while the allele r gives white phenotype in the homozygous genotypes. So, the genotype of the pink orchids would be Rr. A cross between two Rr plants obtain progeny in following genotype ratio:

1/4 RR: 1/2 Rr: 1/4 rr

Here, the R allele is lethal in homozygous genotypes and the progeny ratio become=

1/3 white: 2/3 pink