Allele+Frequencies+Tutorial

Example from a Bio 2 class on the tongue rolling trait.
A survey of a class 22 people was taken and the following results were found:
 * Known information:** Tongue rolling is through to be inherited by a dominant allele (R)
 * 4 people can't roll their tongue (rr - genotype)
 * 18 people can roll their tongue (RR + Rr - genotypes)

Calculating the Allele Frequencies
Let **//p//** stand for the dominant allele (R) and **//q//** stand for (r). Since the total number of alleles in the population is made up of //**p+q**//

//**p+q=1**//
Each individual has **two** alleles, frequency of **RR + Rr + rr = 1**. Therefore we can express this equation as: **//p//² + 2//pq// + //q//² = 1**


 * 1) We know that 8 alleles out of 44 are rr, so **//q//² = 8/44 = 0.18** so **//q// = square root of 0.18 = 0.42**
 * 2) Now we can solve for **//p//. //p// = 1 - //q// = 1 - 0.42** **= 0.58**
 * 3) We can now calculate how many people in the class are likely:
 * RR = **//p//² = 0.34**
 * Rr = **2//pq = 0.48//**
 * //rr =// **//q//² = 0.18**