Illustrates how studying one family's pedigree can reveal an entire history of passing on a genetic disorder such as SCA1.
This animation illustrates how mistakes made during DNA replication are repaired.
DNA's chemical properties can be harnessed for a variety of biotechnology applications.
DNA has a double helix structure. If untwisted, DNA looks like two parallel strands. Each strand has a linear sequence of A, C, G, and T. The precise order of the letters carries the coded instructions. One strand is a complementary image of the other: A always pairs with T, and C always pairs...
The structure of DNA, discovered by James Watson and Francis Crick, suggests a mechanism of replication. The double helix unwinds, and each strand acts as a template for the construction of the new DNA molecule.
Using information from molecular research, this 3-D animation shows how DNA is replicated at the molecular level. It involves an enzyme that unwinds the DNA, and other enzymes that copy the two resulting strands.
Both strands of the DNA double helix act as templates for the new DNA strands. Incoming DNA is unraveled by the enzyme helicase, resulting in the 3' strand and the 5' strand. The 3' strands and the 5' strands are replicated by a DNA polymerase enzyme but in different ways.
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.
Environmental and cultural factors can affect whether a new human mutation becomes common in a population.
A demonstration by Dr. Meyer showing how a balance of molecular elements trigger genetic pathways that determine the sex of a C. elegans worm.
Kangaroo-like hopping when spinal cord excitatory interneurons cross the midline to stimulate both sides.
Dr. Zoghbi demonstrates how mice that have been given the gene responsible for spinocerebellar ataxia 1 (SCA1) are tested on a device called a rotarod to quantify the amount of ataxia present.
Genetic evidence shows that humans evolved in Africa and continue to evolve.
How humans perceive bitter taste, and the evolution of taste perception.
How has the amazing diversity of plants and animals evolved? What can fossils, butterflies, and stickleback fish tell us about the deep common ancestry of all living forms?
Comparing the artificial selection of dogs and corn with the natural selection of the stickleback fish.
The genetic mechanisms by which evolution occurs, and an overview of the evidence for evolutionary theory.
How and why butterflies and fruit flies got their spots, and the fossil record for human evolution.
As part of the 2003 Holiday Lectures on Science, Dr. Bert Vogelstein and Dr. Huda Y. Zoghbi discuss how their patients have led to a deeper understanding of the genetic and molecular bases of neurological disorders and cancer. Thanks to these patients, researchers can now apply the knowledge...
Although there are numerous kinds of cancer, all stem from alterations that allow cell division to outstrip cell demise.
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.
Mutations in key genes can lay waste to the nervous system. By studying large families predisposed to developing these genetic disorders, scientists can identify the responsible altered gene.
Girls with Rett syndrome develop normally for about 18 months and then begin to regress. With the help of affected girls and their families, Dr. Zoghbi and her collaborators searched for the gene responsible for this neurological disorder.
Genetic research benefits health, but also raises thorny ethical issues.
Dr. Friedman shows how leptin rewires neural circuits, and how population studies may identify obesity genes.