TABLE 8.

Preferred and unpreferred synonymous polymorphism and divergence

	Polymorphic changes				Fixed differences
Gene	P → P	P → U	U → P	U → U	P → P	P → U	U → P	U → U
CCA1	2	3	2	2	3	5	6	5
CYT1	2	3	2	1	5	4	2	3
MLS1	3	3	4	0	9	8	8	2
PDR10	1	0	2	1	3	11	11	5
ZDS2	1	1	2	4	1	5	6	6
Total	9	10	12	8	21	33	33	21

P and U, preferred and unpreferred codons, respectively; e.g., P → P is a synonymous substitution from a preferred to a different preferred codon.