NEW APPROACHES TO THE MODELING OF SPECIATION

该项目的总体目标是通过研究各种多基因座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。通常只考虑少量的基因座或数量性状，认为选择较弱，种群大小不变，只研究了极少数主要反映“崎岖适应景观”的选择机制。最近，一个新的比喻“洞穴适应性景观”(Gavrilets1997)被提出，作为一种看似合理的替代传统观点的崎岖适应性景观。这一隐喻是本文提出的研究的核心。本项目将研究：(I)种群和分支的遗传和形态多样性的动态，(Ii)集合种群和杂交区的进化动态，(Iii)共同进化的动态。这里要探讨的生物学问题非常多样。然而，要使用的方法背后有一个统一的主题。这一主题是，生物有机体可以被视为具有数千和数百万元素(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巨大维度的空间中。因此，相当大比例的进化变化预计将发生在近中性网络和有洞穴的适应性景观上。偶然性和偶然性应该在进化动力学中发挥重要作用。在这里，将使用最近在理论进化生物学、数学和物理学中开发的分析方法和广泛的数值模拟相结合的方法来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).