Question

A cross between one blue-flowered foxglove plant and one purple-flowered foxglove plant produced 8 blue-flowered plants and 6 purple-flowered plants. Self-crossing the original blueflowered plant produced only blue-flowered plants. A goat ate the original purple-fowered plant before a self-cross could be performed. Which phenotype is dominant? What is the genotype of the purple-flowered plant? What is the genotype of the blue-flowered plant?

Answer 1

Answer:

The correct answers are:

• Purple flower is the dominant phenotype.
• The genotype of the original purple-flowered must be heterozygous dominant.
• The genotype of blue-colored plant must be homozygous recessive.

The cross between blue-flowered and purple-flowered plant resulted in the production of offspring with both types of phenotype. Thus, either one or both the parent plant must be heterozygous.

In addition, the selfing of blue-flowered plants resulted only in the production of blue-flowered plants. Hence, this must be homozygous in nature.

So, we can conclude that blue was homozygous and purple was hetrozygous.

We know that, trait which is expressed in heterozygous condition is termed as dominant. Hence, the trait of purple color must be dominant and that of blue color must be recessive.

Hence, the genotype of original blue-flowered plant must be homozygous recessive and that of purple-flowered plant must be heterozygous dominant.