Question

How do you test for genetic drift?

Answer 1

Tests for genetic drift:

1. Genetic drift refers to the change in the existing gene frequency of a population due to random chance.
2. For a population, the effective population size( denoted by N_e) controls the magnitude of the genetic drift of that population.
3. If the effective population size is known to us then we can calculate the expected genetic drift of that population.
4. Let's take an example to test the genetic drift.
5. If ‘p’ and ‘q’ are two allele frequencies for a gene subject to genetic drift then the expected variance in the frequency after one generation Genetic drift can be calculated: $$\begin{gathered} Var\left(p\right)=\frac{pq}{2N_e}. \\ Atequilibrium,Var\left(p\right)=p_0{q}_0 \\ Let,p_0=q_0=0.5,N_e=30 \\ Then,Var\left(p\right)=\frac{0.5\times 0.5}{2\times 30}=0.0042 \\ Now,thes\tan darddeviationof\left(p\right)={(0.0042)}^{0.5}=0.06 \end{gathered}$$
6. The standard deviation is the average absolute value of the expected difference between the genetic drift of two-generation in a population.
7. In this way, we can test the genetic drift. The lower the population size, the higher the change in the allele frequency occurs.