Linear correlation between relative CP size and ORG repertoire size was established and used to estimate likely ORG repertoire for the extinct sabertooth cat (Smilodon fatalis).

(a), Log-log regression plot of absolute CP surface area against body mass for 26 species (r2 = 0.83, P<0.001). Residuals from regression constitute relative CP size (RelCP) for each species and are used in all subsequent analyses. (b), Strong positive linear correlation between RelCP and the number of functional ORG (log10) is shown in reduce major axis regression plot (r2 = 0.76, P< 0.001, n=26). (c), Linear correlation between RelCP and total ORG number (functional, pseudogenes) (log10). (d), Axes from figure 2b plot are inverted and the RelCP value (green vertical line) for the sabertooth cat is applied to the regression equation. This predicts Smilodon to have had ca. 600 (581,685) functional ORG. Dotted lines: 95% confidence intervals around regression line. All work done in R.

(a) 26个物种种群的绝对CP表面积与体重的双对数回归图（决定系数r²=0.83，P<0.001）。回归所得残差即为各物种的相对CP大小（relative CP size, RelCP），并应用于后续所有分析。
(b) 约化主轴回归图显示，相对CP大小（RelCP）与功能性ORG（functional ORG）数量的log₁₀转换值之间存在显著正线性相关（r²=0.76，P<0.001，n=26）。
(c) 相对CP大小（RelCP）与总ORG数量（包含功能性基因与假基因）的log₁₀转换值之间的线性相关关系。
(d) 将图2b的坐标轴反转后，将剑齿虎的相对CP大小（绿色垂直线）代入该回归方程，预测刃齿虎（Smilodon）的功能性ORG数量约为600个（置信区间为581~685）。图中虚线为回归线周围的95%置信区间。所有分析均在R统计软件中完成。