Rosas Alexandre, Gordo Isabel, Campos Paulo R A
Departamento de Física, CCEN, Universidade Federal da Paraíba, João Pessoa, Brazil.
Phys Rev E Stat Nonlin Soft Matter Phys. 2005 Jul;72(1 Pt 1):012901. doi: 10.1103/PhysRevE.72.012901. Epub 2005 Jul 5.
We investigate the dynamics of loss of favorable mutations in an asexual haploid population. In the current work, we consider homogeneous as well as spatially structured population models. We focus our analysis on statistical measurements of the probability distribution of the maximum population size N(sb) achieved by those mutations that have not reached fixation. Our results show a crossover behavior which demonstrates the occurrence of two evolutionary regimes. In the first regime, which takes place for small N(sb) , the probability distribution is described by a power law with characteristic exponent theta(d) =1.8 +/- 0.01. This power law is not influenced by the rate of beneficial mutations. The second regime, which occurs for intermediate to large values of N(sb), has a characteristic exponent theta(c) which increases as the rate of beneficial mutations grows. These results establish where genetic drift and clonal interference become the main underlying mechanism in the extinction of advantageous mutations.
我们研究了无性单倍体种群中有利突变丧失的动态过程。在当前工作中，我们考虑了均匀以及空间结构化的种群模型。我们将分析重点放在对那些尚未固定的突变所达到的最大种群规模(N(sb))的概率分布的统计测量上。我们的结果显示出一种交叉行为，这表明存在两种进化模式。在第一种模式中，对于较小的(N(sb)) ，概率分布由特征指数(\theta(d)=1.8\pm0.01)的幂律描述。这个幂律不受有益突变率的影响。第二种模式出现在(N(sb))为中等至较大值时，其特征指数(\theta(c))随着有益突变率的增加而增大。这些结果确定了在有利突变灭绝过程中，遗传漂变和克隆干扰成为主要潜在机制的情况。
