Test cross in plants or in Drosophila involves crossing:
Correct answer: C. The F1 hybrid with a double recessive genotype
- A. Between two genotypes with recessive trait
- B. Between two F1 hybrids
- C. The F1 hybrid with a double recessive genotype
- D. Between two genotypes with dominant trait
Explanation
A test cross is a genetic cross performed to determine the genotype of an organism exhibiting a dominant phenotype. It involves crossing the organism with a homozygous recessive partner. If the organism is homozygous dominant, all offspring will display the dominant phenotype. If the organism is heterozygous, the offspring will exhibit a 1:1 ratio of dominant to recessive traits. Option C correctly describes this scenario. Options A, B, and D do not provide the necessary conditions to reveal the genotype of an organism with a dominant phenotype, as they either involve recessive traits or do not provide clarity about the dominant trait.
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About Inheritance
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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