Question

In a population of 300 spiders, you genotype all individuals for one neutral locus and find the following allelic counts: A1 = 60, A2 = 55, A3 = 280, A4 = 130, A5 = 75. What is the probability that allele A5 is lost due to genetic drift?

Answer 1

Answer:

87.5%

Step-by-step explanation:

The sample space is the total sum of allelic count.

               60 + 55 + 280 + 130 + 75 = 600 counts

The probability that allele A5 is lost due to genetic drift will be the probability of getting A1, A2, A3, A4 only.

              Event A1, A2, A3, A4 =  60 + 55 + 280 + 130 = 525 counts

$Probability = \frac{Number\ of\ ways\ an\ event\ can\ happen}{Total\ number\ of\ outcomes}$

$Pr(allele\ A5\ is\ lost\ due\ to\ genetic\ drift) = \frac{525}{600}$

                                                                  = 0.875

                                                                  = 87.5%

We can calculate using another approach.

2nd Approach

Firstly, we will calculate the probability of getting allele A5 then we find the complement of the answer. The complement of the probability of getting allele A5 is the probability that allele A5 is lost due to genetic drift.

                         $Pr(Getting\ Allele\ A5) = \frac{75}{600}$

                                                   = 0.125

Pr (Allele A5 is lost due to genetic drift) = 1 - Pr(Getting Allele A5)

                                                   = 1 - 0.125

                                                   = 0.875

                                                   = 87.5%