In a plant population, suppose that red flowers (R) are dominant to white flowers (r). In a population of 500 individuals, 25% show the recessive phenotype. How many individuals would you expect to be homozygous dominant and heterozygous for this trait

The correct answer is - Homozygous Dominant (R)= 125

Heterozygous (Rr)= 250

Explanation:

By the  Hardy-Weinberg equation., one can find the value of the recessive, dominant and heterozygous frequency of an individual frequency in a particular frequency. The two important equation are:

       p + q = 1 . . . . . . . . (a)

       p² + 2pq + q²=1 . . . . . (b)

Where, p² is homozygous dominant character and q² is homozygous recessive character and 2pq is the heterozgous genotype or dominant so,

q² = 25% given so q  would be = √25 = 0.5

By equation a p = 1 - 0.5 = 0.5

So the p² would be 25% as well that is = 500×25/100 = 125

2pq =500 - (q²+p²) = 500-(125+125) = 250.

Thus, the correct answer would be =  Homozygous Dominant (R)= 125

Heterozygous (Rr)= 250