Purvis A, Rambaut A
Department of Zoology, University of Oxford, UK.
Comput Appl Biosci. 1995 Jun;11(3):247-51. doi: 10.1093/bioinformatics/11.3.247.
CAIC is an application for the Apple Macintosh which allows the valid analysis of comparative (multi-species) data sets that include continuous variables. Comparison among species is the most common technique for testing hypotheses of how organisms are adapted to their environments, but standard statistical tests like regression should not be used with species data. Such tests assume independence of data points, but related species often share traits by common descent rather than through independent adaptation. CAIC uses a phylogeny of the species in the data set to partition the variance among species into independent comparisons (technically, linear contrasts), each comparison being made at a different node in the phylogeny. There are two partitioning procedures--one used when all variables are continuous, the other when one variable is discrete. The resulting comparisons can be analysed validly in standard statistical packages to test hypotheses about correlated evolution among traits, to estimate parameters such as allometric exponents, and to compare rates of evolution. Previous versions of the package have already been used widely; this version is simpler to use and works on a wider range of machines. The package and manual are freely available by anonymous ftp or from the authors.
CAIC是一款适用于苹果麦金塔电脑的应用程序，它能对包含连续变量的比较（多物种）数据集进行有效分析。物种间的比较是检验关于生物体如何适应其环境假说的最常用技术，但像回归这样的标准统计检验不适用于物种数据。此类检验假定数据点相互独立，但相关物种往往通过共同祖先继承特征，而非通过独立适应。CAIC利用数据集中物种的系统发育关系，将物种间的方差划分为独立比较（从技术上讲，是线性对比），每次比较在系统发育关系的不同节点进行。有两种划分程序——一种用于所有变量均为连续变量的情况，另一种用于一个变量为离散变量的情况。由此产生的比较结果可在标准统计软件包中进行有效分析，以检验关于性状间协同进化的假说、估计诸如异速生长指数等参数，以及比较进化速率。该软件包的早期版本已被广泛使用；此版本使用更简便，且适用于更广泛的机器。该软件包及手册可通过匿名文件传输协议免费获取，或从作者处获得。
