DISSERTATION RESEARCH: Determining the role of horizontal gene transfer in plastid acquisition and endosymbiosis

内生菌向寄主的基因转移是水平基因转移(HGT)的一种特殊形式，是包括叶绿体在内的细胞器进化的关键过程。在细胞器的进化中，来自猎物而不是内共生体的HGT可能同样重要，但随着基因组测序的增加，HGT的流行直到现在才被认识到。这一建议检验了这样的假设，即来自猎物的HGT可以发生在获得叶绿体的早期，并利用甲藻藻类暂时保留从藻类猎物中窃取的叶绿体来促进叶绿体的保留。到目前为止，已鉴定出5个与叶绿体功能有关的基因，系统发育分析表明，这些基因大部分是通过HGT获得的。需要对Dinophysis中的基因进行全面的调查，以确定以叶绿体为靶标的全部基因并确定它们的系统发育起源。HGT和针对被盗的质体的基因之间的强烈相关性将为这一假说提供强有力的支持。这些结果将阐明HGT与Dinophysis叶绿体获得之间的关系。这项研究收集的数据将被用来评估一种与传统内共生理论中概述的不同的细胞器获取策略，一种始于捕食者-猎物关系而不是互惠互利的宿主-内共生关系的策略。这项研究将包括一名本科生的培训。此外，这一数据集将提供给更广泛的科学界，以调查牙藻的其他方面，这些方面通过产生引起腹泻性贝类中毒的毒素而对全球渔业和人类健康产生重大影响。

Gene transfer from endosymbiont to host is a specific form of horizontal gene transfer (HGT) and is a critical process in the evolution of organelles including plastids. HGT from prey, rather than endosymbionts, is perhaps equally important in the evolution of organelles, but with increased genome sequencing the prevalence of HGT is only now being recognized. This proposal tests the hypothesis that HGT from prey can occur early in plastid acquisition and facilitate plastid retention using the dinoflagellate Dinophysis, which temporarily retains plastids stolen from algal prey. Thus far, five genes necessary for plastid function have been identified in Dinophysis, and phylogenetic analyses indicate that the majority of these genes were acquired through HGT. A comprehensive survey of genes in Dinophysis is required to identify the full complement of plastid-targeted genes and determine their phylogenetic origin. A strong correlation between HGT and genes targeted to the stolen plastid would provide strong support for the hypothesis. These results will elucidate the relationship between HGT and plastid acquisition in Dinophysis. The data collected with this research will be used to evaluate a different strategy of organelle acquisition than that outlined in the traditional endosymbiotic theory, one that begins with a predator-prey relationship rather than a mutualistic host-endosymbiont relationship. This study will include the training of an undergraduate student. In addition, this dataset will be available to the broader scientific community to investigate other aspects of Dinophysis, which have a major impact on global fisheries and human health through their production of toxins causing diarrhetic shellfish poisoning.