a particular trait is caused by the homozygous state of recessive autosomal gene. what % of the inidivuduals would be heterozygous for the gene if...
a)16% of the individuals in a given population express the phenotype caused by this gene
b)25% of the individuals in a given population express the phenotype caused by this gene
c)1 of the individuals in a given population express the phenotype caused by this gene
what formula did you use to answer this question?
a)16% of the individuals in a given population express the phenotype caused by this gene
b)25% of the individuals in a given population express the phenotype caused by this gene
c)1 of the individuals in a given population express the phenotype caused by this gene
what formula did you use to answer this question?
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Your teacher/prof is looking for the Hardy-Weinburg Equilibrium.
The equation is p^2 + 2pq + q^2 = 1.
q^2 represents the homozygous recessive genotype, aa.
p^2 represents the homozygous dominant genotype, AA.
2pq, as you might guess is the heterozygous genotype, Aa.
It's also important to know that p + q = 1.
p represents the dominant allele, A.
q represents the recessive allele, a.
(It is very important for your understanding of genetics that you understand how the equation works, not just how to solve problems with it. That's why I'm including all the back information. )
Ok, so for scenario (a), 16% is equal to q^2. Let's state that as q^2 = 16/100 or .16
That means q = .4
We can now solve for p, using p +q = 1. (or 1 - q = p) 1 - .4 = .6
Filling in the variables, the equation now looks like this:
(.6)^2 + 2(.6)(.4) + (.4)^2 = 1
or
.36 + .48 + .16 = 1
These can be expressed in percentages: 36% of the population is homozygous dominant, 48% heterozygous, and 16% homozygous recessive.
You can use that equation to work (b). But for the record, (c) is a trick question (unless you forgot to put in a % sign). Without knowing how large a segment of the population 1 individual is, you cannot use this or any other formula to figure out the genotypes of the other members in the population.
The equation is p^2 + 2pq + q^2 = 1.
q^2 represents the homozygous recessive genotype, aa.
p^2 represents the homozygous dominant genotype, AA.
2pq, as you might guess is the heterozygous genotype, Aa.
It's also important to know that p + q = 1.
p represents the dominant allele, A.
q represents the recessive allele, a.
(It is very important for your understanding of genetics that you understand how the equation works, not just how to solve problems with it. That's why I'm including all the back information. )
Ok, so for scenario (a), 16% is equal to q^2. Let's state that as q^2 = 16/100 or .16
That means q = .4
We can now solve for p, using p +q = 1. (or 1 - q = p) 1 - .4 = .6
Filling in the variables, the equation now looks like this:
(.6)^2 + 2(.6)(.4) + (.4)^2 = 1
or
.36 + .48 + .16 = 1
These can be expressed in percentages: 36% of the population is homozygous dominant, 48% heterozygous, and 16% homozygous recessive.
You can use that equation to work (b). But for the record, (c) is a trick question (unless you forgot to put in a % sign). Without knowing how large a segment of the population 1 individual is, you cannot use this or any other formula to figure out the genotypes of the other members in the population.