DNA: Biology’s Genetic Code

DNA encodes our genetic information and is passed on within cells to maintain living organisms and to produce the next generation. The recognition of DNA as the genetic material and the ensuing identification of its structure and coding mechanism were both revolutionary and foundational. These discoveries led to transformational integration across the biological sciences with a common understanding of this fundamental unit of life! Join this exploration of DNA structure, packaging, replication, and manipulation.

The course utilizes video lectures, research articles, case studies, and molecular models to convey information. The course grade will be based on questions with each video lecture, quizzes, homework, and a final exam.

Lecture 1: DNA Structure

Comprised of only four monomers, DNA serves as thegenetic material of living organisms. We explore how DNA was identifiedas the genetic material, review the characteristics and structure of DNA,examine the information encoded in this interesting macromolecule, and explore implications of variations in DNA size and sequence.

Lecture 2: DNA Organization

We explore how DNA is arranged, packaged, and organized within the cell. We examine chromatin architecture, how chromatin is modified by histones, and how epigenetics can affect gene expression.

Lecture 3: DNA Replication I

We explore the mechanisms by which DNA is copied and the complications that arise due to the asymmetric construction of DNA with respect to its 3' and 5' ends. We examine the dynamic nature of the replication proteins and the exquisite specificity with which these proteinscan catalyze essential biochemical reactions, and how enzymatic activity can be regulated within the larger context of the cell.

Lecture 4: DNA Replication II

We explore further the replication machinerythat allows for the coordination of leading and lagging strand synthesis during DNA replication, a feature of both prokaryotic and eukaryotic DNA replication. We examine the initiation of DNA replication at origins of replication. We also discuss the involvement of nucleosomes and histones in this process, which is a unique feature of eukaryotic DNA. We also examinetermination of DNA replication and the involvement of telomerase in solving a unique problem of eukaryoticDNA replication: shortening of chromosomal endsduring DNA replication.

Lecture 5: DNA Manipulation

We examine the manipulation of DNA. The cell can restore (or sometimes alter) DNA by repairing damage from a variety of environmental sources. Repair of double-stranded breaks includes recombination (or exchanging DNA sequences between two different dsDNAs). We examine methods of DNA amplification, analysis, "cloning," and sequencing. These forms of "manipulating" DNA employ enzymes and functional properties that we have discussed. Our ever-more-efficient and cost-effective ability to sequence and to recombine DNA fragments has transformed biological and biomedical sciences, and much remains to be discovered!