TABLE 2.

Estimates of net mean evolutionary distance and mean evolutionary distance between NDV genotypes^a

^aThe “net mean evolutionary distances” between groups of sequences are shown in white, and the “mean evolutionary distances” are shown in gray above the diagonal. Values below the 0.10 threshold are shown in bold characters. As calculated in MEGA6, the “net mean evolutionary distance” between genotypes X and Y is equal to d_XY − [(d_X + d_Y)/2], where d_XY is the “mean evolutionary distance” between genotypes X and Y and d_X and d_Y are the mean within-genotype distances. Analyses were conducted using the maximum composite likelihood model. The rate variation among sites was modeled with a gamma distribution (shape parameter = 1). The analysis involved 873 nucleotide sequences. Codon positions included were 1st plus 2nd plus 3rd plus noncoding. All ambiguous positions were removed for each sequence pair. There were a total of 1,662 positions in the final data set. Evolutionary analyses were conducted in MEGA6.