Figure 20.2 A Gene Pool A gene pool is the sum of all the alleles found in a population or at a particular locus in that population. This figure shows the gene pool for one locus, X, in a population of diploid organisms. The allele frequencies in this case are 0.20 for X1, 0.50 for X2, and 0.30 for X3 (see Figure 20.10).