Maintenance of ecological polymorphism by frequency-dependent selection

通过频率依赖选择维持生态多态性

• 批准号: RGPIN-2014-04657
• 负责人: Lank, David
• 金额: $ 1.97万
• 依托单位: Simon Fraser University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2015
• 资助国家: 加拿大
• 起止时间: 2015-01-01 至 2016-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=587939
• 关键词: Maintenance; ecological; polymorphism; frequency; dependent

Most species have a single general type of individual in their populations, but in some species, several quite different types co-exist. The most obvious examples is that two sexes coexist, which occurs because both are required for reproduction. My research is asking how different types persist within each sex, in cases where the different types occur due to strong genetic differences. More than one kind of male, or female, are not necessary for reproduction. Why doesn’t one type outcompete the other, driving it to extinction? I am exploring these questions by taking advantage of large differences body size, appearance and behaviour that are caused by single genetic differences in an extraordinary shorebird called the ruff. Most male ruffs have fancy breeding plumages, but, uniquely among birds, these are as individually variable as the coat colours of domestic cats. Birds of different colours behave differently. Dark birds are territorial, while light birds share breeding territories with owners. Females are smaller, and lack fancy plumage. Remarkably, about 1% of males, called ‘female mimics’, have small body sizes, lack fancy plumage, do not display to females, but nonetheless achieve breeding success. I have previously learned that development into one or another male type is controlled by differences at only two genes. Such dramatic effects are unusual. In most cases many interacting genes determine large differences in such characteristics. My studies with this intriguing species ask: (1) What are the exact genes that control development into one kind of male or another, for behaviour, plumage, and body size? Extraordinary advances in the technology for processing DNA is enabling us to 'find genes' that control such functions. (2) How do these same genes express themselves differently in males and females? The gene that makes 'female mimics' also slows down breeding by females that carry it, which seems disadvantageous. Possibly as a result, a higher proportion of birds than expected that carry this gene are males. (3) What controls the sex ratio differences of birds of different types? (4) How do different types of males co-exist in the population? Why doesn't one type out compete the others? My findings will help us understand demonstrate fundamental mechanisms controlling dramatic body size, appearance, and behavioural differences in a vertebrate. These are easier to study in ruffs than in most other animals because they are caused by known genetic differences.

大多数物种在它们的种群中只有一个普通类型的个体，但在一些物种中，几个完全不同的类型共存。最明显的例子是两性共存，这是因为双方都需要生殖。我的研究是问，在由于强烈的遗传差异而出现不同类型的情况下，不同的类型如何在每个性别中持续存在。繁殖不需要一种以上的雄性或雌性。为什么一种类型不能胜过另一种，把它赶尽杀绝？我正在探索这些问题，方法是利用由一种名为Ruff的特殊滨鸟的单一基因差异造成的巨大体型、外貌和行为差异。大多数雄性毛羽都有奇特的繁殖羽毛，但在鸟类中独一无二的是，这些羽毛就像家猫的毛色一样千变万化。不同颜色的鸟有不同的行为。黑鸟是有领地的，而轻鸟与主人共享繁殖领地。雌性较小，缺乏花哨的羽毛。值得注意的是，大约1%的雄性，也就是所谓的“雌性模仿者”，体型较小，缺乏花哨的羽毛，不向雌性展示，但仍取得了繁殖成功。我以前了解到，发育成一种或另一种男性类型只受两个基因的差异控制。这样的戏剧性效果是不寻常的。在大多数情况下，许多相互作用的基因决定了这些特征的巨大差异。我对这一耐人寻味的物种的研究问：(1)究竟是什么基因控制着一种或另一种雄性的发育，决定着行为、羽毛和体型？DNA加工技术的非凡进步使我们能够“找到控制这些功能的基因”。(2)这些相同的基因在男性和女性身上的表达方式有何不同？这种制造“雌性模仿体”的基因还会减缓携带这种基因的雌性的繁殖速度，这似乎是不利的。可能的结果是，携带这种基因的鸟类中，雄鸟的比例高于预期。(3)是什么控制了不同类型鸟类的性别比差异？(4)不同类型的雄性如何在种群中共存？为什么不能有一种比其他类型的更好呢？我的发现将帮助我们理解，展示控制脊椎动物戏剧性的身体大小、外表和行为差异的基本机制。与大多数其他动物相比，在皱纹中研究这些更容易，因为它们是由已知的遗传差异引起的。