Viral cystatin evolution and three-dimensional structure modelling: A case of directional selection acting on a viral protein involved in a host-parasitoid interaction

Table 1 Positive selection analysis among sites and lineages of viral cystatins from Cotesia spp. parasitoid wasps

Site analysis
Models	χ² value	df	P-value for best model	Global ω	ω > 1, parameters	PSS
M0 versus M3	125.00	6	< 0.001	1.31	ω = 2.65, p = 0.310	26, 5, 11*
M8A versus M8	19.57	1	< 0.001	1.21	ω = 2.85, p = 0.289	26, 7, 5*
Branch site analysis
Models	χ² value	df	P-value for best model		ω > 1, parameters (foreground lineage)
M1a versus MA	126.81	2	< 0.01		ω = 11.93, p = 0.232
M3 versus MB	73.20	3	< 0.01		ω = 12.04, p = 0.233

Notes: df is degrees of freedom; PSS is the number of positive selected sites; * corresponds to a posterior probability greater than 95% of having ω > 1 and ** corresponds to a posterior probability greater than 99% of having ω > 1.

ISSN: 1741-7007