In a test cross, if the unknown plant is homozygous dominant, what will be the phenotype of all offspring?

In a test cross, if the unknown plant is homozygous dominant, what will be the phenotype of all offspring?

• A. All dominant
• B. All recessive
• C. Half dominant, half recessive
• D. Mixed

Answer: (A)

In a test cross, one typically crosses an individual with an unknown genotype to an individual that is homozygous recessive for the trait in question. If the unknown plant is homozygous dominant, it will have two dominant alleles. When this plant is crossed with a homozygous recessive individual (which has two recessive alleles), all offspring will inherit one dominant allele from the homozygous dominant parent and one recessive allele from the homozygous recessive parent. Since the dominant allele masks the presence of the recessive allele, all offspring will exhibit the dominant phenotype. This outcome reflects the principles of Mendelian inheritance, where the presence of at least one dominant allele results in the expression of the dominant trait. Therefore, the phenotype of all the offspring in this scenario will be consistent and will display the dominant characteristic.

In a test cross, one typically crosses an individual with an unknown genotype to an individual that is homozygous recessive for the trait in question. If the unknown plant is homozygous dominant, it will have two dominant alleles. When this plant is crossed with a homozygous recessive individual (which has two recessive alleles), all offspring will inherit one dominant allele from the homozygous dominant parent and one recessive allele from the homozygous recessive parent.

Since the dominant allele masks the presence of the recessive allele, all offspring will exhibit the dominant phenotype. This outcome reflects the principles of Mendelian inheritance, where the presence of at least one dominant allele results in the expression of the dominant trait. Therefore, the phenotype of all the offspring in this scenario will be consistent and will display the dominant characteristic.