||P.2 right column bottom paragraph to p.4 left column top paragraph: "From sequence data alone, it is impossible to independently identify Ne [effective population size] and τ [generation time], only their product Neτ can be estimated. [Investigators] fit a phylogenetic model incorporating the coalescent process to sequence data to estimate genealogical trees and coalescent parameters for influenza and measles virus (Figure 1). In this case, [they] estimate Neτ for HA [hemagglutinin] of influenza A (H3N2) at 7.2 years (95% credible interval 6.2-8.4) and Neτ for measles at 124.6 years (100.4-153.9). These estimates give quantification to the visual differences apparent in genealogical trees. [They] arrive at independent estimates of τ via experimental and epidemiological data on the duration of infection, which [they] take as 5 days for influenza (τ = 0.014 years per generation) [primary source 17] and 11 days for measles (τ = 0.030 years per generation) [primary source 14]. [Their] basic results do not depend on these exact estimates. Dividing by τ yields estimates of Ne = 526 (451-611) for influenza and Ne = 4135 (3332-5107) for measles."