Question

Describe the Mendel&rsquo;s monohybrid cross based on any one character.

Accepted Answer

The cross between two organisms, where only one pair of contrasting characters are used is known as a monohybrid cross. The results of the monohybrid cross enabled Mendel to formulate the first law of inheritance, which is the law of dominance.

In the pea plant, the allele of tall (T) is dominant over dwarf (t). When crossed the pure tall plant (TT) and pure dwarf plant, all the individuals obtained in the F₁ generation were heterozygous tall (Tt). The alleles for dwarfness were there in the F₁ generation, but could not be expressed due to their recessive nature. But when F₁ progenies were self-crossed, recessive alleles expressed themselves due to homozygous condition. By self-crossing the F₁ plant, it is proved that recessive alleles do not lose their identity and expressed when present in the homozygous state.

The cross is given below:

The phenotypic ratio of the F₂ generation is 3 (tall) :1 (dwarf)

The genotypic ratio of the F₂ generation is 1 : 2 : 1

Describe the Mendel’s monohybrid cross based on any one character.

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