Ecology and genetics of hybrid animals

杂交越来越被认为是动物进化中的一种多样化力量。高杂交适合度在新奇的、边缘的或动态的生境中更为常见。然而，杂交适合度较高的原因只有部分人知道。我的研究项目采用了田野研究和实验研究相结合的综合方法，结合遗传特征来研究新的遗传组合如何在动态的生态环境中提供更高的适合度。我利用Fundulus杂交复合体的优势，在那里，通常在不同盐度发现的两种鱼类(Fundulus Heterocltes和F.diaphanus)进行杂交，产生有性繁殖和雌核发育杂交。后者由全雌性克隆组成，它们需要来自Fundulus雄性的精子来触发卵子发育。进行生态调查，以确定在中等盐度和/或可变盐度生境，如河口、潮汐急流、沿海湖泊和泻湖中亲本和杂交种的相对分布。同时，通过AFLP标记的全基因组遗传特征，对杂交频率、导入水平和克隆多样性进行了初步估计。通过检查与健康相关的特征，如离子调节能力、野外(移植实验)和实验室(普通花园实验)的存活和生长，将生态和遗传知识结合起来。在这里，固定克隆基因型的可用性特别适合于解开影响适合度成分的表型变异的遗传、母体和环境来源。由于其恒定的遗传背景，克隆也可用于检测杂交种的等位基因表达。这种对自然雌雄配子的综合分析将提供机会来检验关于克隆人生态广度的竞争性假说。这项研究还将与功能和环境生理学和基因组学领域有关，这些领域以异色镰刀菌为模式生物。拟议的研究将涉及一名博士、三名硕士和五名理科学士学生。这些学生将接受从整体角度记录和解释生态、表型和遗传变异的培训。

Hybridization is increasingly recognized as a diversifying force in animal evolution. High hybrid fitness is more frequent in novel, marginal, or dynamic habitats. Causes of higher hybrid fitness, however, are only partly known. My research program employs an integrative approach involving field and experimental studies coupled with genetic characterization to investigate how new genetic combinations can provide higher fitness in dynamic ecological settings. I take advantage of the Fundulus hybrid complex where two fish species (Fundulus heteroclitus and F. diaphanus) typically found at different salinities have hybridized to produce sexually reproducing and gynogenetic hybrids. The latter comprises all-female clones that need sperm from Fundulus males to trigger egg development. Ecological surveys are conducted to establish the relative distribution of parental and hybrid forms in habitats of intermediate and/or variable salinity such as estuaries, tidal rapids, coastal lakes and lagoons. In parallel, preliminary estimates of hybrid frequency, introgression levels and clonal diversity are refined by genome-wide genetic characterization with AFLP markers. Ecological and genetic knowledge are coupled by examining fitness-related traits such as ionoregulation ability, survival and growth in the field (transplant experiments) and in the lab (common garden experiments). Here, the availability of fixed clonal genotypes is particularly appropriate to disentangle the genetic, maternal, environmental sources of phenotypic variation impacting on fitness components. Given their constant genetic background, clones are also useful to examine allelic gene expression in hybrids. This integrated analysis of natural gynogens will offer opportunities to test competing hypothesis on the ecological breadth of clones. This research will also be relevant to the fields of functional and environmental physiology and genomics, which use F. heteroclitus as a model organism. The proposed research will involve one Ph. D., three M. Sc., and five B. Sc students. These students will be trained in documenting and interpreting ecological, phenotypic and genetic variation from a holistic point of view.