Frank A C, Lobry J R
CNRS UMR 5558, Biométrie, Biologie Evolutive, Université Claude Bernard, Villeurbanne, France.
Gene. 1999 Sep 30;238(1):65-77. doi: 10.1016/s0378-1119(99)00297-8.
In the absence of bias between the two DNA strands for mutation and selection, the base composition within each strand should be such that A = T and C = G (this state is called Parity Rule type 2, PR2). At a genome scale, i.e. when considering the base composition of a whole genome, PR2 is a good approximation, but there are local and systematic deviations. The question is whether these deviations are a consequence of an underlying bias in mutation or selection. We have tried to review published hypotheses to classify them within the mutational or selective group. This dichotomy is, however, too crude because there is at least one hypothesis based simultaneously upon mutation and selection.
在两条DNA链之间不存在突变和选择偏差的情况下，每条链内的碱基组成应使得A=T且C=G（这种状态称为奇偶规则类型2，PR2）。在基因组尺度上，即考虑整个基因组的碱基组成时，PR2是一个很好的近似，但存在局部和系统性偏差。问题在于这些偏差是潜在突变偏差还是选择偏差的结果。我们试图回顾已发表的假说，以便将它们归类为突变组或选择组。然而，这种二分法过于粗略，因为至少有一个假说是同时基于突变和选择的。
