Mr. Spock's father was a Vulcan and his mother
was human. Vulcans have pointed ears and hearts on the right side of their
bodies. Assume that a single gene specifies the Vulcan appearance, and
the Vulcan allele is dominant.
Spock has the same appearance as his father. Is it possible for Spock
and a human mate to produce offspring that appear human?
No, because Spock would not mate with a human.
No. Vulcan genes always dominate.
Yes, there is a chance for the recessive alleles to combine.
What is the predicted chance of an offspring of Spock and a human to look like Spock?
10%
50%
25%
75%
Gene frequency is the frequency of a given allele in a population. If the dominant allele occurs 90% of the time, the recessive gene must occur
0%
1%
10%
90%
If the dominant allele occurs 50% of the time, the recessive gene must occur
0%
50%
25%
100%
If the probability of you breaking your arm or leg is 1 in a million (1/106), the probability of you breaking and arm AND a leg is (1/106)2 the multiple of the two probabilities. Likewise, if the frequency of a dominant allele, A, is 90% (or 0.9), the probability of getting two dominant alleles, AA, is
0.1
0.9
0.81
.081
In Question 5, what is the probability of getting
one recessive allele from your father?
10%
100%
1%
90%
Then, what is the probability of getting one dominant and one recessive gene, Aa?
0.1
0.9
0.9 x 0.1
2 x 0.9 x 0.1
If the gene frequencies are equal (0.5 A and 0.5 a) what are the probabilities for homozygous dominant, heterozygous and homozygous recessive?
33% AA, 33% Aa and 33% aa
50% AA, 25% Aa and 25% aa
50% AA, 0% Aa and 50% aa
25% AA, 50% Aa and 25% aa
Use the Hardy-Weinberg Law to answer Questions 9-14. Albinism occurs in every 1 in 10,000 people. What is p, the frequency of the recessive allele (a) for the disease?
p = 0.0001
p = 0.001
p = 0.01
p = 0.1
Now that you have the value of p, what is q (the frequency of the dominant allele, A)?
0.90
0.99
0.10
0.01
If p2 is the frequency of the disease (homozygous recessive), what is the meaning of q2?
The frequency of carriers who do not have the disease.
The frequency of those heterozygous with respect to the disease.
The frequency of homozygous recessive.
The frequency of healthy non-carriers, (AA).
How do you calculate the numerical value of q2?
q2 = (0.99)2
q2 = 2(0.99)
q2 = 2(0.99 x 0.01)
q2 = (0.01)2
How is the numerical value of carriers calculated?
2pq
pq
p2 + q2
p2 x q2
From Question 13, the value of 2pq = 0.0198. How is the number of carriers of albinism in a population of 10,000 calculated?