Table 1. Type I functional divergence and purifying selection analysis for all GRIN2s.

Groups	θ±SE	LRT	P	Functional distance (dF)	Qk>0.67	Qk>0.9
2AB/2CD	0.629±0.082	59.182	<0.01	0.991	82	8
2A/2B	0.223±0.115	3.726	>0.05	0.252	1	0
2A/2C	0.789±0.120	43.184	<0.01	1.555	213	9
2A/2D	0.366±0.083	19.412	<0.01	0.455	7	2
2B/2C	0.695±0.104	44.648	<0.01	1.188	109	6
2B/2D	0.474±0.125	14.256	<0.01	0.642	14	0
2C/2D	0.038±0.133	0.081	>0.05	0.039	0	0
	Negative site % a		Highly negative sites % b		Functional branch length (bF)
2A	40.21		33.52		0.4426
2B	39.33		31.05		0.3525
2C	30.22		22.71		0.7024
2D	19.39		15.44		−0.1207

Functional divergence (θ) for all pairwise comparisons of the GRIN2s were shown as value±standard error, the functional distance between two groups were calculated as –Ln(1-θ), and the functional branch length (bF) of each group were estimated by the least-squares method. Two hundred and twenty-four sites were investigated based on posterior probability (Qk) within GRIN2s.

^aPercentages of sites under negative selection (P<0.1).

^bPercentages of sites under strong negative selection (P<0.05).