We know that 80% of the population are wither WW or Ww, since it is a dominant trait either of these genotypes will make a widow's peak. Therefore, 20% will be ww.
p2 + 2pq + q2 = 1 and p + q = 1
p = frequency of the dominant allele in the population
q = frequency of the recessive allele in the population
p2 = percentage of homozygous dominant individuals
q2 = percentage of homozygous recessive individuals2pq = percentage of heterozygous individuals
q2 = 20% of the population.
20%
0.20, so:
q2 = 0.20
q = SQRT(0.20)
q = 0.4472
a) 0.4472 or 44.72%
b) Use p + q = 1, so q = 0.4472 and p = 1 - 0.4472 = 0.5527
2. Within a population of butterflies, the color brown (B) is dominant over the color white (b), and 40% of all butterflies are white. Given this simple information,. which is something that is likely to be on an exam, calculate the following.
a. The percentage of butterflies in the population that are heterozygous.
b. the frequency of homozygous dominant individuals.
The key to this question is this
40% of all butterflies are whiteTherefore, bb or b2 = 0.40...
Do the same as above.
b = SQRT(0.4) = 0.6324 (this is your q, recessive allele frequency)
Now find p, using p + q = 1... p = 1 - 0.6324 = 0.3675
To find heterozygous, use
2pq = percentage of heterozygous individuals2*p*q = 2*0.3675*0.6324 = 0.4648 or 46.48% of the population possess Bb genotype.
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