Improvement of Undergraduate Molecular Biology Laboratory Curriculum

分子系统学项目的主要目标是在课程中的几门课程中引入一个统一的概念。它通过用现代方法补充传统的教学风格、概念和材料，包括基于发现的学习、现代系统发育方法以及科学家在该领域使用的材料和方法，向人们灌输对进化概念的透彻理解。分子进化和系统发育分析的教学从一年级的课程开始，以发现为基础的有机体分类和进化的练习。学生们得到了几种无脊椎动物的5S rRNA序列，要求他们在物种之间进行成对的比较，并要求他们构建看似合理的进化树。讨论了形态系统发育和分子系统发育之间的不一致性。在本练习中，学生将直观地掌握分子系统学原理，这些原理将在后面的课程中详细学习。作为这项练习的后续行动和后续研究的先决条件，学生们将被介绍分子生物学数据库和互联网上的软件。具体地说，它们针对的是NIH和EMBL、核糖体数据库项目以及CLUSTALW和PHYLIP计划。家庭作业包括搜索和比对选定的5.8S rRNA和短多肽序列。在植物学中，学生使用大小亚基rRNA和rbcL序列来探索非维管植物和维管植物之间的关系。他们从GenBank获得序列，使用CLUSTALW进行比对，然后使用PHYLIP构建系统发育树。学生们在测试植物进化模型的过程中得到了广泛的指导。在动物学中，学生们重新探索从一年级开始的门之间的关系，因为他们更详细地研究动物进化中的具体问题。在高级课程中，主要调查人员与讲师合作，为学生探索找出特定学科的问题。鼓励学生使用文献中的模型来解决问题。通过购买DNA测序设备，定向研究项目正在成为可能。具体的项目使本科生能够在这些领域的专家的指导下调查硅藻、纤毛虫和甲壳类动物进化的问题。该项目的成果可以通过宾夕法尼亚联邦大学生物学家、在线公告栏和传统教育期刊传播。其他对一年级和二年级课程仍有传统组织偏见的大学，如果按照这个项目进行，可以更顺利地过渡到以概念为基础的课程。

The primary objective of the Molecular Phylogeny project is to introduce a unifying concept into several courses in the curriculum. It is inculcating a thorough understanding of evolutionary concepts by complementing traditional teaching styles, concepts, and materials with modern approaches, including discovery-based learning, modern phylogenetic approaches, and the materials and methods used by scientists in the field. Instruction in molecular evolution and phylogenetic analysis begins in the freshman course with a discovery-based exercise on the classification and evolution of organisms. Students are given the 5S rRNA sequences of several invertebrates, asked to make pairwise comparisons between species, and asked to construct plausible evolutionary trees. Discordance between morphological- and molecular-based phylogenies are discussed. In this exercise, students develop an intuitive grasp of the principles of molecular phylogeny that will be studied in detail in later courses. As a follow-up to this exercise and a prerequisite to subsequent studies, students are given an introduction to molecular biology databases and software on the Internet. Specifically, they are directed to the NIH and EMBL, the Ribosomal Database Project, and the CLUSTALW and PHYLIP programs. Homework assignments involve searching and aligning selected 5.8S rRNA and short polypeptide sequences. In Botany, students explore the relationships among nonvascular and vascular plants using small and large subunit rRNAs and rbcL sequences. They obtain sequences from the GenBank, align them using CLUSTALW, then construct phylogenetic trees using PHYLIP. The students are guided extensively through this exercise as they test a model of plant evolution. In Zoology, students re-explore the relationships among phyla begun in the freshman class, as they look in more detail at specific issues in animal evolution. In advanced courses, the principal investigators work with the instructors to identify discipline-specific p roblems for student exploration. Students are encouraged to develop problems using models from the literature. Directed research projects are becoming possible through the acquisition of DNA sequencing equipment. Specific projects enable undergraduate students to investigate problems in diatom, ciliate, and crustacean evolution under the direction of experts in these areas. Results from the project can be disseminated through the Commonwealth of Pennsylvania University Biologists, on-line bulletin boards, and traditional education journals. Other universities that still have a traditional organismic bias to their freshman and sophomore curricula can make the transition to a concept-based curriculum more smoothly if they proceed as this project.