Programa de Genética Humana, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
Biol Res. 2013;46(2):101-19. doi: 10.4067/S0716-97602013000200001.
The Neutral Theory of Evolution (NTE) proposes mutation and random genetic drift as the most important evolutionary factors. The most conspicuous feature of evolution is the genomic stability during paleontological eras and lack of variation among taxa; 98% or more of nucleotide sites are monomorphic within a species. NTE explains this homology by random fixation of neutral bases and negative selection (purifying selection) that does not contribute either to evolution or polymorphisms. Purifying selection is insufficient to account for this evolutionary feature and the Nearly-Neutral Theory of Evolution (N-NTE) included negative selection with coefficients as low as mutation rate. These NTE and N-NTE propositions are thermodynamically (tendency to random distributions, second law), biotically (recurrent mutation), logically and mathematically (resilient equilibria instead of fixation by drift) untenable. Recurrent forward and backward mutation and random fluctuations of base frequencies alone in a site make life organization and fixations impossible. Drift is not a directional evolutionary factor, but a directional tendency of matter-energy processes (second law) which threatens the biotic organization. Drift cannot drive evolution. In a site, the mutation rates among bases and selection coefficients determine the resilient equilibrium frequency of bases that genetic drift cannot change. The expected neutral random interaction among nucleotides is zero; however, huge interactions and periodicities were found between bases of dinucleotides separated by 1, 2... and more than 1,000 sites. Every base is co-adapted with the whole genome. Neutralists found that neutral evolution is independent of population size (N); thus neutral evolution should be independent of drift, because drift effect is dependent upon N. Also, chromosome size and shape as well as protein size are far from random.
进化的中性理论(NTE)提出突变和随机遗传漂变是最重要的进化因素。进化最显著的特征是古生物学时代的基因组稳定性和分类群之间缺乏变异;一个物种 98%或更多的核苷酸位点是单态的。NTE 通过随机固定中性碱基和不产生进化或多态性的负选择(净化选择)来解释这种同源性。净化选择不足以解释这种进化特征,而近乎中性的进化理论(N-NTE)包括负选择,其系数与突变率一样低。这些 NTE 和 N-NTE 命题在热力学上(倾向于随机分布,第二定律)、生物上(反复突变)、逻辑上和数学上(稳定平衡而不是漂变固定)是站不住脚的。在一个位点上,仅通过碱基的反复正向和反向突变以及碱基频率的随机波动,就使得生命组织和固定成为不可能。漂变不是一个定向进化因素,而是物质-能量过程的定向趋势(第二定律),它威胁着生物组织。漂变不能驱动进化。在一个位点上,碱基之间的突变率和选择系数决定了遗传漂变不能改变的碱基的弹性平衡频率。核苷酸之间预期的中性随机相互作用为零;然而,在相隔 1、2……和 1000 多个碱基的二核苷酸碱基之间发现了巨大的相互作用和周期性。每个碱基都与整个基因组共同适应。中立主义者发现,中性进化与种群大小(N)无关;因此,中性进化应该独立于漂变,因为漂变效应依赖于 N。此外,染色体大小和形状以及蛋白质大小都远非随机。