Chap 5 Effect of number of loci on trait distribution


Figure 5.3 The distribution of phenotypic values as the sum of underlying genetic distributions, showing that the sum rapidly converges on a normal distribution as the number of loci increases. The animation assumes two equiprobable alleles at each underlying locus with the three genotypes in Hardy-Weinberg equilibrium. The phenotypic contributions from each genotype are normally distributed with the same standard deviation (0.2) but with means of three genotypes (e.g., aa, Aa, AA) equal to –x, 0 and x, where x is a random variable drawn from a normal distribution with a mean of 0 and a standard deviation of 0.5. This animation is an illustration of the expectation from the Central Limit Theorem, which states that the sum of random variables converges on a normal distribution no matter what the distribution of the underlying variables.