Question

igonore the portion that mentions the lecture, nothing was discussed in lecture. no addidtional information is needed. clear handwriting or typing please.

3. (4 pts. Looking back to the CCR5 data explained during the lecture, we calculated that in a population in Iceland the frequency of the mutated allele was 0.147. How many generations would it take the allele to reach a frequency of 0.5, if a mutation rate of 10% is the only evolutionary force at work? What evolutionary mechanism could potentially reduce this time and how would that happen? Note: the formula presented in class was for alleles that reduced their frequency over time. For this specific exercise, just switch the order of In(po) and In(p)

Answer 1

To calculate the no. Of generations required to change allele frequency by a given amount, euation goes like this,

where p_{​​​​​​t} is the reduced frequency. But in this case the final frequency is more than p_{​​​​​​0}​​​​​ so we take

P+ = po(1 – u) t = log(pt/po) /log(1 – u

P_{​​​​​​t} = 0.147

P​​​​​_{​​​​0}= 0.5

u = 10^-5

Thus

$t= log(0.147/0. 5)/log(1-10^{-5})\Rightarrow t = 122417 \: generations$