Dr. Zoghbi shows how a mouse that has been given the gene responsible for Rett syndrome exhibits some of the same neurological symptoms as human Rett patients.
A quarry site in Nevada carries the evolutionary history of a population of stickleback fish that resided there when it was a freshwater lake.
During the process of trying to elucidate the structure of DNA, Jim Watson made some cardboard models to try to understand how DNA nucleotides are paired. It helped him visualize how hydrogen atoms of paired nucleotides interact with each other to form a symmetrical structure that fits the...
Adam Barrett describes his seven-drug antiretroviral regimen and the importance of adherence.
Aplysia californica is a marine snail with a simple nervous system suitable for research on learning and memory.
A touch to the Aplysia's siphon causes a gill withdrawal, a simple reflex for studying memory.
A live recording of muscle activity from Dr. Jessell's biceps and triceps muscles.
Dr. Brett Finlay shows how bacteria can grow rapidly to incredible numbers, and also explains what limits this explosive growth.
A demonstration by Dr. Meyer showing how a balance of molecular elements trigger genetic pathways that determine the sex of a C. elegans worm.
Air is an invisible gas as are hydrogen and helium. How can you tell if a balloon contains hydrogen? Hydrogen has particular physical and chemical properties that can be tested. Dr. Cech enlists student volunteers to show how a chemical reaction can be used to identify a substance.
Adam Barrett, a nurse who is HIV positive, discusses his first symptoms and the challenges of adhering to a drug regimen.
The fight against dengue fever, and the mosquitoes that carry the virus, is being carried out by "brigadistas" in Managua's neighborhoods. Spanish with English subtitles.
Charles Runckel, a graduate student in the DeRisi lab, uses the Virochip to examine the mystery of bee colony collapse disorder.
Zinhle Thabethe describes how antiretroviral therapy has changed her life.
Are you a night owl or a morning lark? Noted researcher Dr. Seymour Benzer discusses how the difference between he and his wife sparked his interest in the topic of biological clocks.
The bobtail squid swims during the night to hunt. During the day, it burrows to hide from predators.
A demonstration by Dr. Barbara Meyer of how a branched genetic pathway can be affected by mutations in different parts of the pathway.
Corn was originally bred from the teosinte plant by native Mexican farmers. The morphologies of modern-day corn and teosinte plants are compared to illustrate how artificial selection can bring about dramatic changes in plants.
Even when distracted by food, the cat's brain encodes and retains the location of an obstacle.
Without an appropriate catalyst some chemical reactions would be so slow as to appear not to occur at all on the human timescale. However, when catalyzed, these reactions can be very dramatic.
HHMI President Dr. Thomas Cech discusses the path he took to become a scientist and his reaction to receiving the Nobel Prize.
Time-lapse microscopy showing cell division from 1 to 2 to 4 cell stages in C. elegans with fluorescent chromosomes.
Video of the fertilization of the C. elegans oocyte, the fusion of the egg and sperm nuclei, and the egg laying.
Video microscopy of mating between a male and a hermaphrodite C. elegans roundworm.
Video closeup of the C. elegans sperm that moves like an amoeba.