Table 1.

X. laevis paralogs show an enhanced rate of amino acid change relative to X. laevis-X. tropicalis orthologs.

	Amino acid substitutions per site	Nucleotide transversions per synonymous site	Rate of amino acid substitution per unit nucleotide change
Pair	P-dist (σ)	Corr 4 DTv (σ)	P-dist/4 DTv	dN/dS (σ)
L–T	0.0598(2)	0.0973(5)	0.615(4)	0.118(1)
L1–L2	0.0563(3)	0.0707(6)	0.796(8)	0.147(1)
L1–L2/L–T	94.1%	72.7%	129.4%	124.6%

This is demonstrated using both the P-dist/4 DTv measure described in the text, and the conventional ratio of non-synonymous to synonymous substitution rates dN/dS. Both show a 25–30% enhancement in amino acid change. These results are derived from a 513 188 amino acid concatenated, gap-free, multiple sequence alignment (~250 aligned amino acid positions per gene) produced from the 2 135 triplets possessing at least a 50 amino acid aligned block.