Question

The ability of certain people to taste a chemical PTC is governed by a dominant allele T, and the inability to taste PTC by its recessive allelic t. If 24% of a population is homoxygous taster and 40% is heterozygous taster, what is the frequency of t?

Answer 1

• The frequency of the recessive allele t in the population is determined using the Hardy-Weinberg equation.
• In a population, the allele frequencies for a given gene can be represented by p and q, where:
• p = frequency of the dominant allele T.
• q = frequency of the recessive allele t.
• According to the Hardy-Weinberg equation, the alleles frequencies in a population can be calculated as follows:
• p^2 + 2pq + q^2 = 1, where:
• p^2 = frequency of homozygous dominant individuals (TT),
• 2pq = frequency of heterozygous individuals (Tt), and
• q^2 = frequency of homozygous recessive individuals (tt).
• The following information is given:
• 24% of the population is homozygous recessive (tt), so q^2 = 0.24
• 40% of the population is heterozygous (Tt), so 2pq = 0.40
• By substituting the given values, we can solve for the frequency of the recessive allele (q) as follows:
• q^2 = 0.24
• q = √(0.24)
• q ≈ 0.49
• As p + q = 1, now we can calculate the frequency of the dominant allele (T) as follows:
• p = 1 - q
• p = 1 - 0.49
• p ≈ 0.51
• Hence, the frequency of the recessive allele t in the population is approximately 0.49 or 49%.

Allele frequency:

• It is also known as gene frequency which refers to the relative occurrence or proportion of a specific allele  i.e., one of the alternative forms of a gene in a population.
• In humans, each individual has 2 alleles for a given gene, one inherited from each parent.
• This frequency play a crucial role in population genetics and evolutionary studies as they provide insights into how genes are distributed within a population and how genetic variations change over time through the processes like natural selection, genetic drift, and migration.