Albinism, an autosomal recessive trait characterized by an absenc...

Question

Albinism, an autosomal recessive trait characterized by an absence of skin pigmentation, is found in 1 in 4000 people in populations at equilibrium. Brachydactyly, an autosomal dominant trait producing shortened fingers and toes, is found in 1 in 6000 people in populations at equilibrium. For each of these traits, calculate the frequency of

heterozygotes in the population

Accepted Answer

Everyone. Let's take a look at this question together. Albinism is an aal recessive trait characterized by the absence of skin pigmentation. If the population follows Hardy Weinberg equilibrium and 4000 out of a total of 100,000 individuals are homozygous recessive. Which of the following represents the expected frequency of homozygous dominant individuals in the population. Is it answer choice? A 0.2 answer choice, B 0.3 answer choice C 0.5 or answer choice D 0.6. Let's work this problem out together to try to figure out which of the following answer choices represents the expected frequency of homozygous dominant individuals in this population. So we know that since this population follows Hardy Weinberg equilibrium, we are going to use the Hardy Weinberg equilibrium equation which is P squared plus two P Q plus Q squared is equal to one as well as P plus Q is equal to one. And we note that P squared represents the frequency of the homozygous dominant individuals. So we will use the gene A to represent the alleles. And we note that two P Q represents the heterozygous and Q squared represents the homozygous recessive individuals in the population. And we know that 4000 out of a total of 100,000 individuals in this population are homozygous recessive, which means that Q squared, which is the frequency of the homozygous recessive individuals in the population is equal to 4000 out of a total of 100,000 individuals in the population, which is equal to 0.4. And since we want to find out the expected frequency of homozygous dominant individuals, we need to figure out what the frequency is for the dominant allele by using P plus Q is equal to one since P is the frequency of the dominant allele. But first, we have to find the value of Q to find the value of P. And since Q squared is equal to 0.4, that means that Q is equal to the square root of 0.4. So Q is equal to 0.2, which we can plug in Q is equal to 0.2 into the formula P plus Q is equal to one. Since the value of P is equal to one minus Q, which means that P is equal to one minus 0.2. So the value of P is equal to 0.8. And the frequency of homozygous dominant individuals is equal to P squared. So P squared, which is equal to 0.8 squared is equal to 0.64. So the expected frequency of homozygous dominant individuals in the population is answer choice D 0.6. I hope you found this video to be helpful. Thank you and goodbye.

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