DISSERTATION RESEARCH: Phylogenomic insights into the origins and evolution of anticoagulants and bloodfeeding in leeches

抗凝血剂是一类有助于防止血液凝固的蛋白质。 抗凝剂被广泛报道来自吸血水蛭，并广泛用于医学和害虫控制。这项研究将记录水蛭近亲中抗凝剂的存在和演变。在水蛭的直系亲属中发现抗凝血剂将揭示蛋白质的起源，并可能导致新的抗凝血剂化合物的发现。两名代表性不足的市中心高中学生将接受实验室方法的指导和培训。此外，研究人员还将为市中心的高中生制作一个课外教学模块，重点是基于抗凝剂的进化的自然选择。这项研究将重建间的系统发育关系，鳃蛭目，水蛭，将有助于解决长期存在的问题，分段蠕虫的进化。 由此产生的演化框架将用于研究：1）抗凝血剂在蛭形目、鳃蛭目、蚓目和水蛭中的分布; 2）是否有证据表明从水蛭近缘分支到水蛭的正选择沿着，与专性吸血的进化相一致; 3）蛭形目是否是水蛭的姐妹类群，（4）喙蛭类是否为单系，是否与摄食器形态和类群内的家庭关系模式相一致。源材料将在美国和瑞典境内的实地考察中收集。将对每个采样物种的唾液腺进行无菌解剖，然后提取RNA，检查质量并测序。系统基因组学和比较系统发育分析，然后将被用来重建关系和测试的证据之间的正向选择基因。

Anticoagulants are a class of proteins that help prevent the coagulation of blood. Anticoagulants are widely reported from blood-feeding leeches and are used extensively in medicine and for pest control. This research will document the presence and evolution of anticoagulants in the closest relatives of leeches. Finding anticoagulants in immediate leech relatives will shed light on the origin of the proteins and may lead to the discovery of novel anticoagulant compounds. Two underrepresented inner-city high school students will be mentored and trained in laboratory methods. Additionally, the researchers will produce an extracurricular teaching module for inner-city high school students focused on natural selection, based on the evolution of anticoagulants. This research will reconstruct phylogenetic relationships among Acanthobdellida, Branchiobdellida, and leeches that will help resolve long-standing questions about the evolution of segmented worms. The resulting evolutionary framework will then be used to investigate: 1) the distribution of anticoagulants within Acanthobdellida, Branchiobdellida, Lumbriculida, and leeches, 2) whether there is evidence of positive selection along the branches from leech relatives to leeches, coincident with the evolution of obligate blood-feeding, 3) whether Acanthobdellida are the sister group to leeches, and 4) whether the Rhynchobdellida (proboscis leeches) are monophyletic in line with feeding apparatus morphologies, and the pattern of family relationships within the group. Source material will be collected on field expeditions within the U.S.A. and Sweden. Salivary glands will be aseptically dissected for each sampled species and then RNA will be extracted, checked for quality, and sequenced. Phylogenomic and comparative phylogenetic analyses will then be used to reconstruct relationships and test for evidence of positive selection among orthologous genes.