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，更好地了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。通常被认为是一个小数目的基因座或数量性状，选择被认为是弱的，人口规模被认为是恒定的，只有非常有限的选择制度，主要反映了占主导地位的范式“崎岖的适应性景观”进行了研究。最近，一个新的隐喻“多孔的适应性景观”（Gavrilets 1997）已被提出作为一个合理的替代传统的看法崎岖的适应性景观。这一隐喻是本文研究的核心。该项目将调查：（一）动态的遗传和形态多样性（增长）种群和分支，（二）集合种群和杂交区的进化动力学，（三）共同进化动力学。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，生物进化发生在一个具有大量维度的空间中。因此，很大一部分的进化变化预计会发生沿着近中性网络和多孔的适应性景观。偶然性和偶然性应该在进化动力学中扮演重要角色。在这里，最近在理论进化生物学，数学和物理学中开发的分析方法与广泛的数值模拟相结合，将用于考虑自然种群中的各种因素（选择，突变，重组，随机漂移，迁移，灭绝，殖民等）。

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).