Example of a 2×2 contingency table for the conserved/non-conserved codon pattern in one particular gene in human.

aOnly the conserved protein residues were involved. The odds ratio of the number of conserved/non-conserved codon sites between transmembrane and non-transmembrane sites is (86/12)/(61/49) = 5.8 for this contingency table. Because there is one table per one gene, we applied the Mantel–Haenszel procedure to calculate the joint odds ratio for all tables across all genes.

本分析仅纳入保守蛋白质残基。针对该列联表，跨膜位点与非跨膜位点间的保守/非保守密码子位点数量之比的优势比为(86/12)/(61/49)=5.8。由于每个基因对应一张列联表，我们采用曼特尔-亨塞尔（Mantel–Haenszel）检验法，计算所有基因对应全部列联表的合并优势比。