Question

In his analysis of F2 individuals in his one-factor ("monohybrid") crosses, Mendel inferred the genotypes associated with dominant phenotypes by examining F3 produced by selfing the F2. You decide instead to test cross the dominant phenotype F, crossing them to recessive parents. Because you are busy with classes, you examine only eight progeny from each test cross to determine whether an individual F2 is pure breeding" or "hybrid like." What fraction of the dominant-phenotype F2 would you identify as "pure breeding"? Show your work

Answer 1

As per mendelian inheritance dominant phenotypes are expressed due to single dominant allele and recessive phenotypes are not expressed in presence of dominant factors . For expression both recessive alleles should be together in a individual . Here we take case of plant height in pea and elaborate on monohybrid cross in which two traits and one character is selected.

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so pure breeding or homozygous dominant are 25% in F2 , homozygous recessive make same percentage and heterozygous dominant make 50% of F2.

gevuotiondomiant phenotpe TR 2mate vp 75% of F2 eneration desash Tau 3 7T Tau niduichaly have TtTutupe 77 /