SCIENCE, TECHNONOLOGY & SOCIETY 1
Activity 2
Name: CABAG, FRANCIS IAIN Y. Course: BA COMMUNICATION ARTS Date: March 25, 2023
CONCEPTS AND DYNAMICS
1. In a population of 1000 individuals, 180 have kinky hair, 360 have wavy hairy, and the rest
have straight hair. Let us assume that hair type is governed by a pair of alleles, and there
are two types of alleles, S (kinky) and s (straight), with the heterozygote condition being
wavy. Compute the allelic frequencies for hair type in the population. (15 pts.)
Allelic frequencies for hair type in the population:
Let's assume that p and q are the frequencies of S and s alleles, respectively. According to the problem,
we have:
180 individuals have kinky hair, which means they must be SS.
360 individuals have wavy hair, which means they can be either heterozygous (Ss) or homozygous (ss).
The remaining individuals have straight hair, which means they must be ss.
So, we can write the following equations:
p² = 180/1000 = 0.18 (frequency of SS)
2pq + q² = 360/1000 = 0.36 (frequency of Ss + ss)
We can simplify the second equation by substituting p² for SS:
2p(1-p) + q² = 0.36
2p - 2p² + q² = 0.36
q² = 0.36 - 2p + 2p²
We also know that p + q = 1, so we can substitute q = 1 - p:
(1 - p)² = 0.46 - 2p + 2p²
Solving for p, we get:
p = 0.46 - 2p + 2p²
0 = 2p² - 3p + 0.46
p = 0.576 or p = 0.4
Since p + q = 1, q = 0.424 or q = 0.6
Therefore, the allelic frequencies for hair type in the population are:
Frequency of S allele (p) = 0.576 or 0.4
Frequency of s allele (q) = 0.424 or 0.6
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Activity 2
2. Albinism is a rare genetic condition, occurring in only one in every 17,000 to 22,000
individuals in the world (Campbell et al. 2003; Gronskov et al. 2007). Conduct a library or
online research and answer these questions: (20 pts.)
a. What can you conclude about the allelic frequency of the a allele globally?
The a allele causes albinism, which is a recessive condition. Therefore, the frequency of the a
allele can be estimated by the frequency of homozygous recessive individuals (aa) in the
population. If the frequency of albinism is 1 in 17,000 to 22,000 individuals, then the frequency
of aa genotype is:
f(aa) = (1/17000) + (1/22000) / 2 = 0.000051
Since q² represents the frequency of homozygous recessive individuals in a population under
Hardy-Weinberg equilibrium, we can write:
q² = 0.000051
Solving for q, we get:
q = sqrt(0.000051) = 0.0071
The frequency of the a allele is q = 0.0071.
b. Where do you think the a allele would be more commonly found, among the
heterozygotes (Aa) or the homozygote recessives (aa)? Why do you say so?
The a allele would be more commonly found among the heterozygotes (Aa) because the
frequency of the recessive allele (q) is very low (0.0071), so the chance of finding two copies of it
in a population is also low. Therefore, most carriers of the a allele are likely to be heterozygotes.
c.
What happens to an individual who is albino (aa) or who has very low or lacks
melanin pigments in the hair, skin and eyes?
An individual who is albino (aa) or who has very low or lacks melanin pigments in the hair, skin,
and eyes is more susceptible to sunburn, skin cancer, and visual impairments. This is because
melanin is responsible for protecting the skin and eyes from the harmful effects of UV radiation
d. Based on your answer in c, how would you explain the frequency of the a allele?
The frequency of the a allele can be explained by the fact that it causes a recessive
condition (albinism) that is associated with various health problems and increased susceptibility to
UV radiation. As a result, individuals with two copies of the a allele (aa genotype) have lower
fitness and are less likely to survive and reproduce, which can reduce the frequency of the a
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SCIENCE, TECHNONOLOGY & SOCIETY 1
Activity 2
allele in the population over time. However, the frequency of the a allele may also be
influenced by genetic drift, founder effects, or consanguinity, which can increase the chance of
the allele becoming fixed or lost in a population by chance. Therefore, the low frequency of
the a allele in the global population is likely due to a combination of these factors.
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