Question

How is the Hardy-Weinberg equation used to predict the recurrence of X-linked recessive traits?

Short answer

The Hardy-Weinberg equation assists in predicting the recurrence of X-linked recessive traits by evaluating the allele frequencies in a population. By applying this equation, it is possible to ascertain the prevalence rates of affected males, carrier females, and hence, provide valuable insights into the potential recurrence of these traits.

Step-by-step solution

Understanding the Hardy-Weinberg Principle

The Hardy-Weinberg principle states that allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences. The equation is as follows: \(p^2 + 2pq + q^2 = 1\), where \(p^2\) represents the frequency of one homozygous genotype, \(2pq\) represents the frequency of the heterozygous genotype and \(q^2\) represents the frequency of the other homozygous genotype.

Understanding X-linked Traits

In X-linked recessive disorders, males are more likely to be affected because they only have one X chromosome and thus, only one copy of the gene in question. Females, on the other hand, are less likely to be affected because they would have to inherit two affected genes (one from each parent).

Applying the Hardy-Weinberg Equation to X-linked Traits

When applying the Hardy-Weinberg equation to X-linked recessive disorders, only females are used in the calculation of \(p^2 , 2pq , q^2\) and males are categorized into either \(p\) or \(q\). The frequency of the recessive allele (q) in the population can be found by calculating the square root of the frequency of affected males. Once q is known, p can be calculated by subtracting q from 1. The frequency of carrier (heterozygous) females can then be calculated using 2pq.