Doe

Herbert Boyer

Stanley N. Cohen

Paul Berg

Herbert Boyer

Stanley N. Cohen

DNAs are called cloning vectors (a vector is a delivery agent). They are typically plasmids or viral DNAs.

3. Joining two DNA fragments covalently. The enzyme DNA ligase links the cloning vector and DNA to be cloned. Composite DNA molecules comprising covalently linked segments from two or more sources are called recombinant DNAs.

4. Moving recombinant DNA from the test tube to a host cell that will provide the enzymatic machinery for DNA replication.

5. Selecting or identifying host cells that contain recombinant DNA.

The methods used to accomplish these and related tasks are collectively referred to as recombinant DNA technology or, more informally, genetic engineering.

Much of our initial discussion will focus on DNA cloning in the bacterium Escherichia coli, the first organism used for recombinant DNA work and still the most common host cell. E. coli has many advantages: its DNA metabolism (like many other of its biochemical processes) is well understood; many naturally occurring cloning vectors associated with E. coli, such as plasmids and bacteriophages (bacterial viruses; also called phages), are well characterized; and techniques are available for moving DNA expeditiously from one bac terial cell to another. We also address DNA cloning in other organisms, a topic discussed more fully later in the chapter.

Essentials of Human Physiology

Essentials of Human Physiology

This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.

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