In equation (3), the author inadvertently omitted a 2. The correct equations is as below: w = (1-2μdel)n where w is the mean fitness of the population ldel , is the mean deleterious mutation rate per functional nucleotide site per generation, and n is the number of functional nucleotide sites in the genome. The correct Table 1 is shown below. (Table presented). The addition of the factor 2 to equation (3) affects numerical values throughout the article, which have also been corrected. Finally, the supplementary table has been removed. The author thanks Ben Galeota-Sprung and Paul Sniegowski for discovering the omission of the number "2" from equation (3) and Fei Yuan for recalculating the values in Table 1.