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Question
A test cross involves crossing an individual of unknown genotype with an individual of known genotype that usually is ______ for the trait in question.
Options
homozygous dominant
homozygous recessive
heterozygous
incompletely dominant
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Solution
A test cross involves crossing an individual of unknown genotype with an individual of known genotype that usually is homozygous recessive for the trait in question.
Explanation:
A test cross involves crossing an individual with an unknown genotype, but showing the dominant phenotype, with an individual that is homozygous recessive for the trait in question. This allows the determination of whether the unknown genotype is homozygous dominant or heterozygous based on the phenotypes of the offspring. If any recessive phenotype offspring appear, it indicates the unknown parent is heterozygous; if all offspring show the dominant phenotype, the unknown parent is homozygous dominant.
