You cross a heterozygous pea plant with round and yellow see

You cross a heterozygous pea plant with round and yellow seeds with a pea plant having wrinkled and green seeds. what is the probability that the offspring will have either round and green seeds or wrinkled and yellow seeds?

What is the probability that the offspring will have either round and yellow seeds or wrinkled and yellow seeds?

Solution

Assume that the gene coding for round peas is R and the gene coding for wrinkled peas is r. Similarly, the gene coding for yellow peas is Y and the gene coding for green peas is y.

The genotype of heterozygous pea plant with round and yellow seeds is Rr Yy; and the genotype of a pea plant having wrinkled and green seeds (rr yy). Cross between these two will have the progeny with the following genotypes:

Rr Yy* rr yy --à Rr Yy (1/4, round, yellow peas), R_ yy (1/4, round, green peas), rr Y_ (1/4, wrinkled, yellow peas), rr yy (wrinkled, green peas).

The probability that the offspring will have either round and green seeds (R_ yy) or wrinkled and yellow seeds (rr Y_) is = The probability of R_ yy + The probability of rr Y_ - the probability of occurrence of both R_ yy and rr Y_

= ¼ + ¼ - (1/4*1/4) = ½ - 1/16 = 7/16

The probability that the offspring will have either round and yellow seeds or wrinkled and yellow seeds ¼ or 25% = ¼ + ¼ - (1/4*1/4) = ½ - 1/16 = 7/16