Sexually-antagonistic effects in red deer

马鹿的性拮抗作用

• 批准号: NE/E017053/1
• 负责人: Loeske Kruuk
• 金额: $ 62.38万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FE017053%2F1
• 关键词: Sexually; antagonistic; effects; red; deer

Evolutionary biologists are continually puzzled by the following problem: natural selection should remove genetic variation that affects the fitness of individuals, yet, when measured, there is often quite a lot of genetic variation for fitness. One possible explanation for the persistence of genetic variation in a population is that, in those species which have two sexes, the genes (alleles) that make a successful male are different from those that make a successful female. A particular gene may be good for males but not be good for females, so that a male with this gene would be relatively successful / and father many offspring / but his daughters would not be. We call this phenomenon sexual antagonism. As a consequence of the opposing selection in males and females, different versions of the gene will be maintained in the population. Sexually-antagonistic effects are likely to be especially important in a species experiencing extensive sexual selection, in which one sex (usually males) is bigger than females, and has developed weaponry such as antlers or horns or spectacular colouration, characteristics which enhance mating success. Sexually-antagonistic effects have been well-explored using theoretical models, and there is empirical support for their existence from laboratory studies of fruit flies, but they have rarely been investigated in nature. In this study we will investigate sexually-antagonistic selection in a wild population of a sexually-dimorphic mammal, red deer. The data set is particularly useful for this study because we have records on the individual life histories, including all breeding attempts, of several thousand deer measured across 34 years. In many cases we also have their skull, jaws, leg bones and cast antlers. Most individuals have been sampled for DNA profiling, from which pedigrees (or family trees) of individuals can be constructed, stretching for up to ten generations of deer. We also have blood samples and can collect faecal samples in which we can measure hormone levels, and finally we have information about the density and weather conditions in which each animal has lived. Long-term studies of individually-recognised wild animals such as these are an important source of information on many aspects of ecology and evolutionary biology. In the first and major part of the study we will use our pedigree information to test for sexually-antagonistic genetic effects. In particular, we will test whether successful males have less successful female relatives, whereas successful females have less successful male relatives. Theoretical models predict that the genes underlying sexually-antagonistic selection will be concentrated on the X chromosome, and we will investigate this question using the known differences in the inheritance of X chromosomes from different ancestors. We will then measure the selection pressures associated with sexually-antagonistic effects. We will test the hypothesis that males with especially 'masculine' body proportions should have higher breeding success than males whose body proportions are more similar to those of females, and vice versa. Because we are working on a wild population experiencing natural environmental conditions, we can also determine the extent to which all these pressures are affected by variation in environmental and ecological conditions. Finally, we will explore one possible mechanism for these effects, via an investigation of associations between testosterone levels and differences in morphology and breeding success, in both males and females.

进化生物学家一直被以下问题所困扰：自然选择应该消除影响个体适应性的遗传变异，然而，当测量时，通常有相当多的遗传变异用于适应性。种群中遗传变异持续存在的一个可能解释是，在那些有两性的物种中，使成功的雄性与雌性成功的基因（等位基因）是不同的。一个特定的基因可能对雄性有利，但对雌性不利，所以一个有这个基因的雄性会相对成功，生下很多后代，但他的女儿不会。我们称这种现象为性对抗。由于男性和女性的相反选择，种群中将保留不同版本的基因。在经历广泛性选择的物种中，性对抗效应可能特别重要，其中一种性别（通常是雄性）比雌性大，并且已经发展出武器，如鹿角或角或壮观的色彩，这些特征可以提高交配成功率。性拮抗效应已经使用理论模型进行了很好的探索，并且从果蝇的实验室研究中得到了它们存在的经验支持，但它们很少在自然界中进行研究。在这项研究中，我们将调查性拮抗选择在野生种群的性二型哺乳动物，红鹿。该数据集对这项研究特别有用，因为我们记录了34年来测量的数千只鹿的个体生活史，包括所有繁殖尝试。在许多情况下，我们也有他们的头骨，下巴，腿骨和铸造鹿角。大多数个体都被取样进行DNA分析，从中可以构建个体的谱系（或家谱），最多可以延伸到十代鹿。我们也有血液样本，可以收集粪便样本，我们可以测量激素水平，最后我们有关于每种动物生活的密度和天气条件的信息。对这些个体识别的野生动物的长期研究是生态学和进化生物学许多方面的重要信息来源。在研究的第一部分，也是主要部分，我们将使用我们的谱系信息来测试性拮抗基因效应。特别是，我们将测试是否成功的男性有不太成功的女性亲属，而成功的女性有不太成功的男性亲属。理论模型预测，性拮抗选择的基础基因将集中在X染色体上，我们将利用不同祖先X染色体遗传的已知差异来研究这个问题。然后，我们将测量与性对抗效应相关的选择压力。我们将测试的假设，特别是男性的“阳刚”的身体比例应该有更高的繁殖成功率比男性的身体比例更相似的女性，反之亦然。因为我们正在研究经历自然环境条件的野生种群，我们还可以确定所有这些压力受到环境和生态条件变化影响的程度。最后，我们将探讨这些影响的一个可能的机制，通过调查睾酮水平和形态差异和繁殖成功之间的关联，在男性和女性。

项目成果

Relative costs of offspring sex and offspring survival in a polygynous mammal.

• DOI: 10.1098/rsbl.2016.0417
• 发表时间: 2016-09
• 期刊: Biology letters
• 影响因子: 3.3
• 作者: Froy H;Walling CA;Pemberton JM;Clutton-Brock TH;Kruuk LE
• 通讯作者: Kruuk LE

Quantitative Genetics in the Wild

野外定量遗传学

• DOI: 10.1093/acprof:oso/9780199674237.003.0010
• 发表时间: 2014
• 作者: Kruuk L