Why females mate once: from genes to populations

为什么雌性只交配一次：从基因到种群

• 批准号: NE/H015604/1
• 负责人: Tom Price
• 金额: $ 38.87万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2011
• 资助国家: 英国
• 起止时间: 2011 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FH015604%2F1
• 关键词: Why; females; mate; once; genes

Some female animals mate once in their life while others mate with many males each day. This results in enormous differences between species in everything from their physiology and behaviour, to how their social systems are arranged. 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 goes on to mate with another male, who will father some of her offspring. This evolutionary pressure on males has caused the evolution of male traits that reduce female remating rates. The establishment of harems in red deer, elephant seals and gorillas are well known examples. Male honeybees genitalia burst inside the female in an effort to block her reproductive tract and prevent her mating with other males. Females in turn have often evolved traits that allow them to avoid control by males, and remate with males of their choosing. Finding the genes underlying female remating would be a big step forward in understanding all this variation. I will search for these genes using the fruit fly Drosophila subobscura. Female flies of this species from Greece remate, whereas those from England do not. Fortunately, the flies are reproductively compatible, so I can crossbreed flies from Greece and England over several generations. This will mix the genes they carry each generation, resulting in many lines of flies that contain a random mix of Greek and English DNA. Then I can test these flies for willingness to remate. Some will be willing to remate despite inheriting only a small amount of DNA from the Greek (willing to remate) population. This will tell me that genes important for willingness to remate must be found in that section of DNA. I can work out which sections of DNA are Greek and which are English by looking at tiny differences in the DNA of flies from the two populations at regular intervals along each chromosome. I will be able to determine how many areas of the genome are important for remating, and will link this to genes examined in closely related species that scientists think may be important in controlling remating. If we can understand which genes cause remating, this will help us understand the mechanisms and consequences better. Moreover, if we can use this knowledge to develop ways to prevent remating in pest species, such as mosquitoes and medflies, many insect control techniques will become much more effective. Remating also seems to be very important in preventing the spread of selfish genes that distort sex ratios. In Tunisian populations of this fly about 20% of flies carry a driving X chromosome called SRS. 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 SRS chromosome all their Y bearing sperm die and all their offspring inherit the SRS X chromosome. This allows the SRS chromosome to spread as it is passed on to more offspring that the normal X, but it also causes male carriers to only have daughters, and to produce less sperm than normal males. This can cause populations to mostly consist of females, and potentially could wipe entire populations out due to a total lack of males. Work in related species has shown that if females mate with multiple males the small amounts of sperm produced by carrier males is usually swamped by the large amounts of sperm transferred by normal males, and the driving X cannot spread. But in D. subobscura, SRS is only found in the Southern populations where females remate, and is never found in the Northern populations where females mate once. I will investigate why this happens by setting up many small laboratory populations of Greek and English flies, with SRS at 20%, set up at different temperatures. I will track the frequency of SRS over many generations, and will be able to determine the conditions under which SRS can spread, and why it is not found in the Northern single mating populations.

有些雌性动物一生只交配一次，而有些则每天与许多雄性交配。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。许多动物高度适应雌性频繁交配的系统。如果一只雄性与之交配的雌性继续与另一只雄性交配，后者将成为她的一些后代的父亲，那么雄性通常会有更少的后代。这种对雄性的进化压力导致了雄性特征的进化，降低了雌性的再交配率。在红鹿、象海豹和大猩猩中建立后宫是众所周知的例子。雄性蜜蜂的生殖器在雌性蜜蜂体内爆裂，试图堵住她的生殖道，阻止她与其他雄性蜜蜂交配。反过来，雌性往往进化出一些特征，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。找到雌性再交配背后的基因将是理解所有这些变异的一大步。我将用果蝇来寻找这些基因。来自希腊的这一物种的雌蝇重新交配，而来自英国的则没有。幸运的是，苍蝇是繁殖兼容的，所以我可以杂交苍蝇从希腊和英国几代。这将混合它们每一代携带的基因，导致许多含有希腊和英国DNA随机混合的果蝇品系。然后我就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，尽管他们只从希腊人（愿意重新交配）那里继承了少量的DNA。这将告诉我，在DNA的这一部分中，必须找到对再婚意愿很重要的基因。我可以通过观察两个种群果蝇的DNA中的微小差异，在每条染色体的沿着有规律地观察，来确定哪些DNA片段是希腊的，哪些是英国的。我将能够确定基因组中有多少区域对再交配很重要，并将其与科学家认为在控制再交配方面可能很重要的密切相关物种中检测的基因联系起来。如果我们能了解哪些基因导致了再交配，这将有助于我们更好地理解其机制和后果。此外，如果我们能够利用这些知识来开发防止害虫物种（如蚊子和地中海果蝇）再次交配的方法，许多昆虫控制技术将变得更加有效。在防止扭曲性别比例的自私基因的传播方面，再生似乎也非常重要。在突尼斯的果蝇种群中，大约20%的果蝇携带一种名为SRS的驱动X染色体。正常的X染色体会遗传给一半的雄性后代，而另一半则会遗传他的Y染色体。但是，当男性携带SRS染色体时，所有携带Y染色体的精子都会死亡，所有后代都会继承SRS X染色体。这使得SRS染色体可以传播，因为它可以传递给比正常X更多的后代，但它也导致男性携带者只生女儿，并且比正常男性产生更少的精子。这可能导致种群主要由女性组成，并可能由于完全缺乏男性而消灭整个种群。相关物种的研究表明，如果雌性与多个雄性交配，携带者雄性产生的少量精子通常会被正常雄性转移的大量精子所淹没，并且驱动X无法传播。但在D.因此，SRS仅在雌性再交配的南方种群中发现，而在雌性交配一次的北方种群中从未发现。我将通过建立许多希腊和英国苍蝇的小实验室种群来研究为什么会发生这种情况，SRS为20%，设置在不同的温度下。我将追踪SRS在多代中的频率，并将能够确定SRS可以传播的条件，以及为什么在北方单一交配种群中没有发现SRS。

项目成果

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

True polyandry and pseudopolyandry: why does a monandrous fly remate?

• DOI: 10.1186/1471-2148-13-157
• 发表时间: 2013-07-25
• 期刊: BMC evolutionary biology
• 影响因子: 3.4
• 作者: Fisher DN;Doff RJ;Price TA
• 通讯作者: Price TA

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

Males do not prolong copulation in response to competitor males in the polyandrous fly Drosophila bifasciata

• DOI: 10.1111/j.1365-3032.2012.00836.x
• 发表时间: 2012-09-01
• 期刊: PHYSIOLOGICAL ENTOMOLOGY
• 影响因子: 1.5
• 作者: Lize, Anne;Price, Thomas A. R.;Hurst, Gregory D. D.
• 通讯作者: Hurst, Gregory D. D.

Assessment of rival males through the use of multiple sensory cues in the fruitfly Drosophila pseudoobscura.

• DOI: 10.1371/journal.pone.0123058
• 发表时间: 2015
• 期刊: PloS one
• 影响因子: 3.7
• 作者: Maguire CP;Lizé A;Price TA
• 通讯作者: Price TA