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SouravSeptember 8, 2024

On the basis of Mendel’s observations, predict the results from the following crosses with peas: (a) A tall (dominant and homozygous) variety crossed with a dwarf variety. (b) The progeny of (a) self-fertilized. (c) The progeny from (a) crossed with the original tall parent. (d) The progeny of (a) crossed with the original dwarf parent.

On the basis of Mendel’s observations, predict the results from the following crosses with peas: (a) A tall (dominant and homozygous) variety crossed with a dwarf variety. (b) The progeny of (a) self-fertilized. (c) The progeny from (a) crossed with the original tall parent. (d) The progeny of (a) crossed with the original dwarf parent.

Sourav
SouravSeptember 8, 2024

Answer

(a) A tall (dominant and homozygous) variety crossed with a dwarf variety

Cross: TT (tall, homozygous dominant) × tt (dwarf, homozygous recessive)

Results:

  • Genotypes of Offspring: All progeny will have the genotype Tt.
  • Phenotypes of Offspring: All progeny will exhibit the tall phenotype because the dominant allele (T) will mask the effect of the recessive allele (t).

(b) The progeny of (a) self-fertilized

Cross: Tt × Tt

Results:

  • Genotypes of Offspring:
    • TT: 1/4 (25%)
    • Tt: 2/4 (50%)
    • tt: 1/4 (25%)
  • Phenotypes of Offspring:
    • Tall: 3/4 (75%) (TT and Tt)
    • Dwarf: 1/4 (25%) (tt)

(c) The progeny from (a) crossed with the original tall parent

Cross: Tt (progeny of (a)) × TT (original tall parent)

Results:

  • Genotypes of Offspring:
    • TT: 1/2 (50%)
    • Tt: 1/2 (50%)
  • Phenotypes of Offspring:
    • All progeny will be tall because both genotypes (TT and Tt) result in the dominant tall phenotype.

(d) The progeny of (a) crossed with the original dwarf parent

Cross: Tt (progeny of (a)) × tt (original dwarf parent)

Results:

  • Genotypes of Offspring:
    • Tt: 1/2 (50%)
    • tt: 1/2 (50%)
  • Phenotypes of Offspring:
    • Tall: 1/2 (50%) (Tt)
    • Dwarf: 1/2 (50%) (tt)

These predictions are based on Mendel’s principles of segregation and dominance, which describe how alleles are inherited and expressed.

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