NEW APPROACHES TO THE MODELING OF SPECIATION

该项目的总体目标是通过研究各种多位点模型的动态和静态行为，更好地理解导致物种形成和多样化的生物过程。现有的物种形成建模方法在几个方面存在缺陷。通常只考虑少量的位点或数量性状，选择被认为是弱的，种群规模被认为是恒定的，只有非常有限数量的选择制度被研究，这些选择制度大多反映了“崎岖适应性景观”的主导范式。最近，人们提出了一个新的比喻，即“有洞的适应性景观”（Gavrilets, 1997），作为对崎岖的适应性景观的传统观点的合理替代。这个隐喻是本文研究的核心。该项目将调查：(1)（生长）种群和枝的遗传和形态多样化动态，(2)超种群和杂交带的进化动态，(3)共同进化动态。这里要探讨的生物学问题是多种多样的。然而，所使用的方法背后有一个统一的主题。这个主题是，生物有机体可以被视为具有成千上万个元素（例如基因或DNA碱基对）的非常长的序列。因此，从数学的角度来看，生物进化发生在具有大量维度的空间中。因此，相当大比例的进化变化预计将发生在接近中性的网络和有洞的适应性景观上。偶然性和偶然性应该在进化动力学中发挥主要作用。在这里，结合了最近在理论进化生物学、数学和物理学中发展起来的分析方法，以及广泛的数值模拟，将用于考虑自然种群中运行的各种因素（选择、突变、重组、随机漂移、迁移、灭绝、殖民化等）。

The overall aim of this project is to better understand biological processes leading to speciation and diversification through a study of the dynamic and static behavior of various multilocus models. Existing approaches to the modeling of speciation are deficient in several ways. Usually a small number of loci or quantitative traits are considered, selection is assumed to be weak, population size is considered to be constant, and only a very limited number of selection regimes mostly reflecting the dominant paradigm of "rugged adaptive landscapes" have been studied. Recently a new metaphor of "holey adaptive landscapes" (Gavrilets 1997) has been put forward as a plausible alternative to the conventional view of rugged adaptive landscapes. This metaphor is the core of the research proposed here. This project will investigate: (i) dynamics of genetic and morphological diversification in (growing) populations and clades, (ii) evolutionary dynamics of metapopulations and hybrid zones, (iii) coevolutionary dynamics. The biological questions to be approached here are very diverse. However, there is a unifying theme underlying the methods to be used. This theme is that biological organisms can be viewed as very long sequences with thousands and millions elements (e.g. genes or DNA base pairs). Thus, from a mathematical point of view, biological evolution takes place in a space with an enormous number of dimensions. Consequently, a significant proportion of evolutionary changes are expected to happen along nearly neutral networks and on holey adaptive landscapes. Chance and contingency should play a major role in evolutionary dynamics. Here, a combination of analytical methods recently developed in theoretical evolutionary biology, mathematics, and physics and extensive numerical simulations will be used to take into account various factors operating in natural populations (selection, mutation, recombination, random drift, migration, extinction, colonization etc).