Powell J R, Caccone A
Department of Biology, Yale University, New Haven, Connecticut 06511.
J Mol Evol. 1990 Mar;30(3):267-72. doi: 10.1007/BF02099996.
This paper emanated from a conference concerning the value, accuracy, and technical considerations of DNA-DNA hybridization for evolutionary studies. Our laboratory has been performing the so-called TEACL (tetraethylammonium chloride) method, and we have amassed sufficient data to indicate that this method is very powerful if performed properly with correct analyses. Here we address five technical considerations: (1) We present empirical data that size correction for tracer length is legitimate and accurate. (2) We show that the error of delta Tm measurement does not significantly increase with increasing distance up to at least 10 degrees C. (3) The error distribution for delta Tm does not deviate from the expected normal distribution indicating parametric statistics are probably legitimate for analyses. (4) Using a known phylogeny we examined the resolving power of the technique by showing that at least five taxa can be correctly placed in phylogenies with a maximum delta Tm of 2.5 degrees C. (5) To date, all our data sets based on DNA-DNA hybridization are very robust with respect to analytical procedures in that every algorithm used on the data sets has yielded identical trees with nearly identical branch lengths. Nevertheless, we point out that theoretical analyses of distance data (as generated by DNA-DNA hybridization) are lacking, especially with regard to tests of the molecular clock hypothesis.
本文源自一场关于DNA-DNA杂交用于进化研究的价值、准确性及技术考量的会议。我们实验室一直在采用所谓的TEACL（四乙基氯化铵）方法，并且我们已经积累了足够的数据，表明如果正确进行并加以正确分析，该方法非常有效。在此，我们阐述五个技术考量：（1）我们给出经验数据，表明对示踪长度进行大小校正合理且准确。（2）我们表明，ΔTm测量误差在至少增加10摄氏度的范围内，不会随着距离增加而显著增大。（3）ΔTm的误差分布与预期的正态分布没有偏差，这表明参数统计可能适用于分析。（4）利用已知的系统发育关系，我们通过表明至少五个分类单元可以在最大ΔTm为2.5摄氏度的系统发育中被正确定位，来检验该技术的分辨能力。（5）迄今为止，我们基于DNA-DNA杂交的所有数据集在分析程序方面都非常稳健，因为对这些数据集使用的每种算法都产生了几乎相同分支长度的相同树状图。然而，我们指出，距离数据（如DNA-DNA杂交产生的数据）的理论分析尚缺，尤其是在分子钟假说的检验方面。
