Fig. 3
From: The effects of sample size on population genomic analyses – implications for the tests of neutrality
Sample size effects on Tajima D T statistics. a θ and π were estimated for synonymous (θ S and π S ) and nonsynonymous sites (θ N and π N ) using different sample sizes. While relationships between sample size and θ was significant (P < 0.01) those between sample size and θ were not (P = 0.06). b Scatter plot shows the Tajima D T estimated for nonsynonymous (D TN ) and synonymous sites (D TS ) using different sample sizes of human exomes. The relationships were significant at the 1 % level. c Relationship between the magnitude of selection pressure on protein-coding genes (dN/dS) and the difference (δ DT ) in Tajima D T estimated using large (N = 512) and small (N = 16) number of exomes. The plot shows the comparative patterns of the significant relationships observed for neutral (δ DTS ) and constrained (δ DTN ) sites. Each data point indicates the δ DTS or δ DTN estimated using the genes belong to a selection intensity category (eg. dN/dS < 0.1). The correlation involving constrained sites was significant (P < 0.01) but that of neutral sites was not (P = 0.48)