New Insights on the Evolutionary History of Aphids and Their Primary Endosymbiont Buchnera aphidicola

Table 2

Yates' chi-square tests for the accelerated genes classified by functional category in four B. aphidicola strains compared in pairs. Acceleration is based on Tajima’s relative rate tests. The total number of comparisons for each particular category and pair of strains is shown in brackets ( ). A/B: number of accelerated genes in A compared to B and in B compared to A, respectively.

Observed	Pairs of strains
Functional category	BAp/BSg	BAp/BBp	BAp/BCc	BSg/BBp	BSg/BCc	BBp/BCc
(1) Information storage and processing	5/12 (160)	0/54 (160)	0/137 (162)	0/47 (158)	0/122 (160)	1/86 (160)
(2) Protein processing, folding, and secretion	1/1 (25)	0/11 (24)	0/19 (25)	0/10 (24)	0/18 (25)	0/14 (24)
(3) Cellular processes	0/0 (10)	0/5 (10)	0/7 (10)	0/3 (10)	0/7 (10)	1/7 (10)
(4) Metabolism	2/9 (103)	3/34 (103)	0/86 (104)	2/32 (104)	0/88 (105)	0/61 (106)
(5) Cell envelope	0/0 (14)	1/7 (13)	0/12 (14)	1/7 (13)	0/12 (14)	0/10 (13)
(6) Poorly characterized	1/1 (33)	1/10 (34)	0/29 (35)	0/7 (32)	0/23 (33)	0/15 (34)
Total	9/23 (345)	5/121 (344)	0/290 (350)	3/106 (341)	0/270 (347)	2/193 (347)
Expected	Pairs of strains
Functional category	BAp/BSg	BAp/BBp	BAp/BCc	BSg/BBp	BSg/BCc	BBp/BCc
(1) Information storage and processing	4.17/10.67	2.33/56.28	0.00/134.23	1.39/49.11	0.00/124.50	0.92/88.99
(2) Protein processing, folding and secretion	0.65/1.67	0.35/8.44	0.00/20.71	0.21/7.46	0.00/19.45	0.14/13.35
(3) Cellular processes	0.26/0.67	0.15/3.52	0.00/8.29	0.09/3.11	0.00/7.78	0.06/5.56
(4) Metabolism	2.69/6.87	1.50/36.23	0.00/86.17	0.91/32.33	0.00/81.70	0.61/58.96
(5) Cell envelope	0.36/0.93	0.19/4.57	0.00/11.60	0.11/4.04	0.00/10.89	0.07/7.23
(6) Poorly characterized	0.86/2.20	0.49/11.96	0.00/29.00	0.28/9.95	0.00/25.68	0.20/18.91
χ ^2𝑠 (with Yates’ correction, 5 d.f.)	0.501/0.933	3.491/1.908	0.000/0.195	4.776/2.762	0.000/0.720	7.455/1.598
𝑃 value	.992/.968	.625/.862	1.000/.999	.444/.737	1.000/.982	.189/.902