Institute of Science and Technology Austria, AT-3400 Klosterneuburg, Austria.
Proc Natl Acad Sci U S A. 2022 Sep 6;119(36):e2123152119. doi: 10.1073/pnas.2123152119. Epub 2022 Aug 29.
Selection accumulates information in the genome-it guides stochastically evolving populations toward states (genotype frequencies) that would be unlikely under neutrality. This can be quantified as the Kullback-Leibler (KL) divergence between the actual distribution of genotype frequencies and the corresponding neutral distribution. First, we show that this population-level information sets an upper bound on the information at the level of genotype and phenotype, limiting how precisely they can be specified by selection. Next, we study how the accumulation and maintenance of information is limited by the cost of selection, measured as the genetic load or the relative fitness variance, both of which we connect to the control-theoretic KL cost of control. The information accumulation rate is upper bounded by the population size times the cost of selection. This bound is very general, and applies across models (Wright-Fisher, Moran, diffusion) and to arbitrary forms of selection, mutation, and recombination. Finally, the cost of maintaining information depends on how it is encoded: Specifying a single allele out of two is expensive, but one bit encoded among many weakly specified loci (as in a polygenic trait) is cheap.
选择在基因组中积累信息——它引导随机进化的群体朝着在中性条件下不太可能出现的状态（基因型频率）发展。这可以通过实际的基因型频率分布与相应的中性分布之间的 Kullback-Leibler（KL）散度来量化。首先，我们表明，这种群体水平的信息对基因型和表型水平的信息设置了上限，限制了选择可以多精确地指定它们。接下来，我们研究了信息的积累和维持是如何受到选择成本的限制的，选择成本以遗传负荷或相对适应度方差来衡量，我们将这两者与控制理论中的控制 KL 成本联系起来。信息积累率受群体大小乘以选择成本的上限限制。这个界限非常普遍，适用于各种模型（Wright-Fisher、 Moran、扩散）和任意形式的选择、突变和重组。最后，信息的维持成本取决于其编码方式：从两个中指定一个等位基因代价很高，但在许多弱指定的基因座（如多基因性状）中指定一个比特则很便宜。
