Table 6 Key to evolutionary events asserted in Figure 7

1

Escape of aroQ•pheA and tyrA from the ancestral gyrA > serC > aroQ•pheA > hisH _b > tyrA > aroF > cmk > rpsA > himD supraoperon. Origin of an aroQ•tyrA fusion. Origin of the aroA _{Iα_Y} > aroQ•tyrA operon. Addition of tyrR. Addition of third aroA _Iα species: aroA _{Iα_F}.

2

Fusion of aroQ•pheA with aroA _Iβ pseudogene of unknown origin. Replacement of hisH _b by aspC duplicate linked with three ORFs.

3

Dissociation of gyrA and serC.

4

Removal of all genes intervening between aroQ•pheA and aroQ•tyrA.

5

Dissociation of aroF from both serC and cmk > rpsA > himD. Insertion of trpR within the intervening region between aroQ•pheA and aroQ•tyrA.

6

Dissociation of serC > hisH _b > aroF from cmk > rpsA > himD.

7

Loss of aroA _{Iα_Y} from tyr operon.

8

aroF becomes dissociated from hisH _b, and aroA _{Iα_Y} is removed from the tyrA operon.

9

ORF > gyrA is inserted after aroF.

10

aroQ•tyrA becomes a pseudogene.

11

hisH _b is lost.

12

himD is lost.

13

cmk, himD and aroA _{Iα_Y} > aroQ•tyrA are lost.

14

aroF, himD, aroQ•pheA, and aroA _{Iα_Y} > aroQ•tyrA are lost.

15

All intervening genes between aroQ•pheA and aroQ•tyrA are eliminated.

16

pheA domain of aroQ•pheA becomes a pseudogene.

17

Insertion of ycaL between aroF and cmk.

18

Insertion of ORF between aroF and ycaL.

19

Insertion of ORF between aroQ•pheA and aroQ•tyrA.