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Polyandry and sex ratio drive

一妻多夫制和性别比例驱动

基本信息

批准号：
NE/I025905/1
负责人：
Gregory Hurst
金额：
$ 5.69万
依托单位：
University of Liverpool
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2012
资助国家：
英国
起止时间：
2012 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FI025905%2F1
关键词：
Polyandry sex ratio drive

项目摘要

Some females mate once in their lifetime while others mate with many different males. This results in enormous differences between species in everything from their physiology and behaviour, to how their social systems are arranged and their population dynamics. Many animals are highly adapted to a system where females mate frequently. A male will generally have fewer offspring if a female he mates with remates to another male, as generally the last male to mate sires the subsequent offspring. This pressure on males to prevent female remating has caused the evolution of traits that reduce female remating such as mate guarding and the transfer of molecules in the ejaculate that suppress female receptivity. Females in turn have evolved traits that allow them to avoid control by males, and remate with males of their choosing. However, despite decades of research and plentiful between-species variation, we know little about why females have evolved to mate as often as they do. This lack of knowledge derives from lack of an 'easy' lab species in which variation in female remating rate is present in nature. We have recently found that females of the North American fruit fly D. pseudoobscura flies mate more frequently in Northern populations that Southern, and that this is determined by genetic differences between the populations. We will observe and collect flies in nature to find out how they live, and replicate these conditions in the laboratory to work out the circumstances under which females benefit from mating with many males. This species is also a 'genetic model, and gives us an opportunity to find the genes underlying female remating, which would be a big step towards understanding this variation. We can crossbreed flies from Montana (Northern USA, high remating) and Arizona (Southern USA, low remating) over several generations. This will result in lines of flies that contain a random mix of Northern and Southern genes. We can then test these flies for willingness to remate. Some will be willing to remate despite inheriting only a few genes from the Northern (willing to remate) population, indicating genes for high willingness to remate must be found in that section of the genome. By looking at tiny differences in the genome of flies from the two populations at regular intervals along each chromosome, we will be able to determine how many areas of the genome are important for remating. We will compare this to genes examined in closely related fly species suggested to be important in controlling female remating.Our previous work has shown that female remating rate is very important for controlling the frequency of selfish genes that distort sex ratios. In Southern populations, the selfish X-chromosome SR is common. Normal X-chromosomes are passed on to half a male's offspring, while the other half inherits his Y chromosome. But when males carry the SR chromosome all their Y bearing sperm die during production and all their offspring inherit the SR X chromosome. This allows the SR chromosome to spread as it is passed on to more offspring that the normal X chromosome and can cause populations to consist mainly of females, and if SR spread to a high enough frequency can wipe out entire populations due to not producing any males. However, female remating reduces the transmission of the driving chromosome. We will create mathematical models to work out whether the fitness benefits we find for polyandry in different environments are sufficient to control the abundance of SR, and hence population sex ratio. We will work out whether SR is ever likely to escape this regulation by females, and spread to such high levels that it causes populations to go extinct.

有些雌性一生只交配一次，而另一些则与许多不同的雄性交配。这导致了物种之间的巨大差异，从生理和行为，到社会系统的安排和种群动态。许多动物高度适应雌性频繁交配的系统。一个雄性如果与之交配的雌性再与另一个雄性交配，通常会有更少的后代，因为通常最后一个交配的雄性会产生随后的后代。雄性阻止雌性再交配的压力导致了减少雌性再交配的特征的进化，例如配偶守卫和射精中抑制雌性接受性的分子转移。反过来，雌性进化出的特征使它们能够避免被雄性控制，并与自己选择的雄性重新交配。然而，尽管几十年的研究和丰富的物种间的变化，我们知道很少为什么女性已经进化到交配频繁，因为他们这样做。这种知识的缺乏源于缺乏一个“容易”的实验室物种，其中雌性再交配率的变化是存在于自然界中。我们最近发现，雌性的北美果蝇D。伪暗蝇在北方种群中比在南方种群中交配更频繁，这是由种群之间的遗传差异决定的。我们将在自然界中观察和收集苍蝇，以了解它们是如何生活的，并在实验室中复制这些条件，以确定雌性与许多雄性交配的情况。这个物种也是一个“遗传模型”，给了我们一个机会来找到雌性再交配的基因，这将是理解这种变异的一大步。我们可以将来自蒙大拿州（北方美国，高再交配）和亚利桑那州（南方美国，低再交配）的苍蝇杂交几代。这将导致含有北方和南方基因随机混合的果蝇品系。然后我们可以测试这些苍蝇是否愿意重新交配。有些人会愿意重新交配，尽管只遗传了北方（愿意重新交配）人群的几个基因，这表明在基因组的这一部分中必须找到高度愿意重新交配的基因。通过观察两个种群果蝇基因组中每一条染色体沿着有规律的微小差异，我们将能够确定基因组中有多少区域对再交配很重要。我们将比较这一基因密切相关的苍蝇物种研究建议是重要的控制女性remating.We以前的工作表明，女性remating率是非常重要的控制频率的自私基因扭曲性别比例。在南方人群中，自私的X染色体SR是常见的。正常的X染色体会遗传给一半男性的后代，而另一半则继承他的Y染色体。但是，当男性携带SR染色体时，所有携带Y染色体的精子都会在生产过程中死亡，所有后代都会继承SR X染色体。这使得SR染色体能够传播，因为它传递给更多的后代，而不是正常的X染色体，并可能导致种群主要由女性组成，如果SR传播到足够高的频率，可能会由于不产生任何男性而消灭整个种群。然而，雌性再交配减少了驱动染色体的传递。我们将创建数学模型来计算我们在不同环境中发现的一妻多夫制的健身益处是否足以控制SR的丰度，从而控制人口性别比。我们将弄清楚SR是否有可能逃脱雌性的这种调节，并传播到如此高的水平，以至于导致种群灭绝。

项目成果

期刊论文数量（9）

专著数量（0）

科研奖励数量（0）

会议论文数量（0）

专利数量（0）

Winter is coming: hibernation reverses the outcome of sperm competition in a fly.

DOI：
10.1111/jeb.12792
发表时间：
2016-02
期刊：
Journal of evolutionary biology
影响因子：
2.1
作者：
Giraldo-Perez P;Herrera P;Campbell A;Taylor ML;Skeats A;Aggio R;Wedell N;Price TA
通讯作者：
Price TA

Opposite environmental and genetic influences on body size in North American Drosophila pseudoobscura.

DOI：
10.1186/s12862-015-0323-3
发表时间：
2015-03-21
期刊：
BMC evolutionary biology
影响因子：
3.4
作者：
Taylor ML;Skeats A;Wilson AJ;Price TA;Wedell N
通讯作者：
Wedell N

Can patterns of chromosome inversions in Drosophila pseudoobscura predict polyandry across a geographical cline?

DOI：
10.1002/ece3.1165
发表时间：
2014-08
期刊：
ECOLOGY AND EVOLUTION
影响因子：
2.6
作者：
Herrera, Paul;Taylor, Michelle L.;Skeats, Alison;Price, Tom A. R.;Wedell, Nina
通讯作者：
Wedell, Nina

Strong hybrid male incompatibilities impede the spread of a selfish chromosome between populations of a fly.