If all the offspring from a test cross are of the dominant phenotype, is the parent with the dominant phenotype homozygous or heterozygous? Briefly explain how you know.

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∻Answer∻ ⚹ The parent with the dominant phenotype is homozygous. ⚹ ∻Solution∻ ‖ a ⋮ Test cross: A test cross involves crossing an individual with a dominant phenotype (but unknown genotype) with an individual that is homozygous recessive for the trait. ‖‖ b ⋮ Offspring phenotypes: If all offspring display the dominant phenotype, it indicates that the parent with the dominant phenotype must be homozygous dominant (AA). ‖‖ c ⋮ Genotype determination: If the parent were heterozygous (Aa), we would expect a 1:1 ratio of dominant to recessive phenotypes in the offspring. ‖ ∻Key Concept∻ ⚹ Homozygous dominant genotype results in all offspring showing the dominant phenotype in a test cross. ⚹ ∻Explanation∻ ⚹ In a test cross, if the parent with the dominant phenotype is homozygous (AA), all offspring will inherit at least one dominant allele, resulting in the dominant phenotype. If the parent were heterozygous (Aa), some offspring would inherit the recessive allele from both parents, showing the recessive phenotype. ⚹◊What is the expected genotype ratio in the offspring of a test cross if the parent with the dominant phenotype is heterozygous?⍭ Generate me a similar question◊

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