In a population of guinea pigs, short hair is dominant to long hair. If 25 percent of a breeder's guinea pigs have long hair, what is the frequency of the recessive allele (q) ? 5 percent 15 percent 25 percent 50 percent

Answer: If 25 percent of a breeder's guinea pigs have long hair (p²), the frequency of the recessive allele (q) is 50%.

Explanation: Since long hair is dominant over short hair, let's denote long hair as HH and short hair as hh. Note that the question didn't indicate that the 25% of the guinea pigs with long hair are heterozygous for the trait. Therefore, we assume that they are homozygous (HH) long hair.

According to Hardy-Weinberg, for two alleles p and q, p + q = 1 where p represents the dominant allele and q represents the recessive allele.

From the question, p² = 25% = 25/100 = 0.25

p = √0.25 = 0.5

Since p + q = 1,

q = 1 - p = 1 - 0.5 = 0.5

Converting 0.5 to percentage, we get 0.5 x 100 = 50%.

Therefore, the frequency of recessive allele (q) is 50%.