highly significantp = 0.005
However, the test for positive selection at individual codon sites (PAML model M1 and M2) was highly significant (χ 2 = 10.66 with 2 df , p = 0.005), identifying two codons subject to selection (dn/ds > 1), codon #1 (dn/ds = 3.71; p = 0.015) and codon #16 (dn/ds = 3.65; p = 0.034; see Figure 1 ).