TABLE 2.

Relative-rate tests for comparing the molecular evolutionary rates of the 16S rRNA gene and fusA gene between the symbionts of C. columbae, the symbionts of tsetse flies, and the symbionts of grain weevils

Gene	Lineage		Outgroup	K1a	K2b	Difference of distance (K1 − K2)	Rate ratio (K1/K2)	Pc
	1	2
16S rRNA	Symbionts of C. columbaed	Symbionts of tsetse fliese	S. marcescensf	0.027	0.009	0.018	3.1	0.00059
gene	Symbionts of C. columbaed	Symbionts of grain weevilsg	S. marcescensf	0.026	0.010	0.016	2.7	0.00092
fusA	Symbiont of C. columbaeh	Symbiont of tsetse fliesi	E. colij	0.025	0.001	0.024	25.0	0.0020
	Symbiont of C. columbaeh	Symbiont of grain weevilsk	E. colij	0.022	0.001	0.021	22.0	0.0034

^aK1, estimated mean distance between lineage 1 and the last common ancestor of lineages 1 and 2.

^bK2, estimated mean distance between lineage 2 and the last common ancestor of lineages 1 and 2.

^cP values were generated using the program RRTree (35).

^dSymbionts of C. columbae from Sapporo, Japan (GenBank accession no. AB303382), and Buenos Aires, Argentina (GenBank accession no. AB303386).

^eSodalis glossinidius symbionts of tsetse flies Glossina morsitans (GenBank accession no. AY861701) and Glossina palpalis (GenBank accession no. AY861703).

^fSerratia marcescens (GenBank accession no. AF124042).

^gSymbionts of grain weevils Sitophilus oryzae (GenBank accession no. AF005235) and Sitophilus zeamais (GenBank accession no. AF005235).

^hSymbionts of C. columbae from Utah (GenBank accession no. EU021696) and from Brisbane, Australia (GenBank accession no. EU021697).

ⁱSodalis glossinidius, symbiont of tsetse fly G. morsitans (GenBank accession no. AF426459).

^jEscherichia coli (GenBank accession no. X00415).

^kSymbiont of grain weevil S. zeamais (GenBank accession no. AF426460).