NSFDEB-NERC: The origin of reproductive parasitism in the Amazon Molly

这个项目将通过探索一个明显的生殖悖论来研究复杂的性状是如何进化的。绝大多数物种都有两种性别，两者都需要繁殖。但有一种生殖方式，雌核发育，似乎结合了联合收割机一个看似不可能的特征组合。在这种模式下，卵子必须由不同物种的雄性受精，但雄性提供的基因不会被整合到后代中，因此所产生的后代在遗传上与它们的母亲相同。这种繁殖模式需要几个重要的进化变化的进化：排斥父亲的DNA，雄性的损失，以及二倍体卵子的形成。在一个单一的进化步骤中发生大的转变是极不可能的，但这是普遍的解释。在拟议的项目中，研究人员将通过复制导致亚马逊莫莉鱼起源的进化途径来形成一个合成的雌核发育物种。数学模型将指导现有物种及其杂交种的实验。这项研究还将通过研讨会和培训机会为多名年轻科学家提供公众宣传。这项研究将通过两个现有物种的杂交人工形成雌核发育物种，确定从一个物种到另一个物种最有可能的进化途径。现有的物种来自德克萨斯州和墨西哥，新物种来自自然杂交事件。为了追溯这一物种的进化，研究小组将使用几种数学技术，包括微分方程和蒙特-卡罗模拟，以模拟一组独特性状进化的最可能途径，包括单性性，未减数卵的形成和克隆性。目前的想法假设所有这些变化都发生在一个进化步骤中，但这似乎不太可能。在模型的指导下，将进行大规模的杂交实验，以在实验室中实际形成雌核发育物种。这个实验将涉及杂交有性鱼类，产生的F1个体之间的对方，和回交。每一个独特的交叉将进一步特征化基因组，遗传，和形态学。这个奖项反映了NSF的法定使命，并已被认为是值得通过评估使用基金会的智力价值和更广泛的影响审查标准的支持。

This project will examine how complex traits evolve by exploring an apparent reproductive paradox. The vast majority of species have two sexes and both are needed to reproduce. But one mode of reproduction, gynogenesis, seems to combine a seemingly impossible combination of traits. In this mode, eggs have to be fertilized by males of a different species, but the genes provided by males are not incorporated into the offspring so that the resulting offspring are genetically identical to their mothers. This reproductive mode requires the evolution of several important evolutionary changes: rejection of the father's DNA, the loss of males, and the formation of diploid eggs. Large transitions in a single evolutionary step is highly unlikely, but this is the prevailing explanation. In the proposed project, the researchers will form a synthetic gynogenetic species by replicating the evolutionary pathway that led to the origin of the fish, the Amazon molly. Mathematical models will guide experiments that cross existing species and their hybrids. This research also will provide outreach to the public via workshops and training opportunities for multiple young scientists.The research will artificially form a gynogenetic species through hybridization of two existing species, determining the most likely evolutionary pathway from one to the other. The existing species are from Texas and Mexico, and the new species resulted from a natural hybridization event. To retrace the evolution of this species, the research team will use several mathematical techniques, including differential equations and Monte-Carlo simulations to model the most likely pathway for the evolution of a unique set of traits, including unisexuality, formation of unreduced eggs, and clonality. Current thinking hypothesizes that all of these changes happened in one evolutionary step, but this seems unlikely. Guided by the models, a large-scale crossing experiment will be conducted to actually form a gynogenetic species in the laboratory. This experiment will involve crossing sexual fishes, the resulting F1 individuals amongst each other, and backcrosses. Every unique cross will further be characterized genomically, genetically, and morphologically.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.