Question

In a monohybrid cross what will be percentage of heterozygous offspring in F4 – generation -
(1) 25%
(2) 50%
(3) 12.5%
(4) 6.25%

Answer 1

In Mendel's "Experiment 1," true-breeding pea plants with spherical seeds were crossed with true-breeding plants with dented seeds. (Spherical seeds are the dominant characteristic.) Mendel collected the seeds from this cross, grew F1-generation plants, let them self-pollinate to form a second generation, and analyzed the seeds of the resulting F2 generation. The results that he obtained, and that you would predict for this experiment are:

A.1/2 the F1 and 3/4 of the F2 generation seeds were spherical.B.1/2 the F1 and 1/4 of the F2 generation seeds were dented.C.All of the F1 and F2 generation seeds were spherical.D.3/4 of the F1 and 9/16 of the F2 generation seeds were spherical.E.All the F1 and 3/4 of the F2 generation seeds were spherical.

Answer 2

Answer is option (3) 12.5%

Explanation:

When two monohybrid plants (YY) and (yy) are crossed, then according to Punnet square,

F2 generation has 25% YY, 50% Yy and 25% yy

F3 generation has 37.5% YY, 25% Yy and 37.5% yy

F4 generation has 43.75% YY, 12.5% Yy and 43.75% yy

Here, Yy is the heterozygous genotype.