A sample is put on a Virochip microarray, and results are compared to databases of all known viral sequences.
A molecular menagerie of small molecules is displayed, with two particular molecules singled out for attention: rapamycin and furrowstatin, which are discussed in the remainder of Dr. Schreiber's lectures on chemical genetics.
Microarray technology is useful for screening many small molecules at once. Automated devices have made it possible for thousands of different small molecules to be printed as an array of spots on a glass slide. A single type of protein which has been tagged with a fluorescent marker can then be...
Somatic cell nuclear transfer (SCNT) is a technique for cloning. The nucleus is removed from a healthy egg. This egg becomes the host for a nucleus that is transplanted from another cell, such as a skin cell. The resulting embryo can be used to generate embryonic stem cells with a genetic match...
PCR is a standard laboratory technique that allows amplification of specific segments of DNA based on complementarity.
After a chemical biologist has made many novel small molecules by diversity-oriented synthesis, the next step is to find those that are useful. Molecules need to be "screened." Conceptually, screening is like using proteins as a custom filter to catch potentially useful small molecules.
One technique for discovering small molecules of biological relevance is to expose cultured cells to a variety of small molecules and look for changes in the cells' appearance, behavior or other measurable qualities.
A new gene can be inserted into a loop of bacterial DNA called a plasmid. This is done by cutting the plasmid DNA with a restriction enzyme, which allows a new piece of DNA to be inserted. The ends of the new piece of DNA are stitched together by an enzyme called DNA ligase. The genetically...
Polymerase chain reaction, or PCR, is a technique for making many copies of a specific DNA sequence. DNA is repeatedly heated and cooled in the presence of primers that bracket the desired sequence and of the enzyme Tac polymerase. In as few as 30 cycles, a billion copies of the target sequence...
Fred Sanger developed the first technique for sequencing DNA. DNA is replicated in the presence of chemically altered versions of the A, C, G, and T bases. These bases stop the replication process when they are incorporated into the growing strand of DNA, resulting in varying lengths of short...
In shotgun sequencing many copies of the entire genome are "blown up" into millions of small fragments. Each small fragment is sequenced. Powerful computers then assemble the individual fragments into the original configuration. Repeat sequences pose a problem for this approach because their...
A useful technique for narrowing down the location of a gene involves comparing the chromosomes of affected siblings. Two sisters with Rett syndrome allow researchers an opportunity to map the most likely location of the gene by excluding areas of the chromosome that are not alike.
Gene chips, also called DNA microarrays, have a broad range of applications in current research, including enabling researchers to measure the activity of thousands of genes simultaneously. Dr. Eric Lander describes the process used to manufacture gene chips.
An interview with Dr. DeRisi.
Video microscopy demonstrating how sperm from an infertile male can be injected into a female egg.
How a microarraying robot delivers hundreds of small molecules to a series of slides.
Robotic equipment makes it possible to screen massive chemical libraries in just a matter of days.
Somatic cell nuclear transfer (SCNT) is performed looking through a microscope and using small glass pipettes to handle human eggs and to remove and transfer nuclei from one cell to another.
What do humans, flies, and worms have in common? More than you might think. See how transgenic organisms are engineered, and how they enable researchers to study genetic diseases.
Dr. Melton describes the process used to extract DNA from a cell and to analyze it on a gene chip.
Watch two leading virus researchers explain how they use both simple and sophisticated technologies to detect and fight infectious agents.
New technologies like the Virochip harness DNA's properties to identify and fight new viruses.
Understanding the immune response is essential to developing safe vaccines for dengue and other diseases.
The SARS epidemic was successfully halted by a global research effort to identify a new virus.
The identification of hundreds of genes involved in the formation and spread of cancer is leading to promising new methods for diagnosis, prevention, and treatment.