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Showing 1-34 of 34 Resources
  • The Biology of Skin Color

    The Biology of Skin Color

    Short Films

    (18 min 58 sec) This film explores the hypothesis that different tones of skin color in humans arose as adaptations to the intensity of ultraviolet radiation in different parts of the world.

  • Seeing Single Molecules Move

    Seeing Single Molecules Move

    Animations

    (1 min 40 sec) Single-molecule analysis using super-resolution microscopes reveals that transcription factors are not usually found bound to their binding sites on DNA.

  • DNA Sequence Technology Improves Cancer Treatment

    DNA Sequence Technology Improves Cancer Treatment

    Clips

    (2 min 6 sec) Dr. Charles Sawyers discusses how the identification of most cancer genes could transform cancer into a chronic disease.

  • The Double Helix

    The Double Helix

    Short Films

    (16 min 53 sec) This film tells the story of the scientists and the evidence involved in one of the most important scientific quests of the 20th century: the discovery of the structure of DNA.

  • The Origin of Species: Lizards in an Evolutionary Tree

    The Origin of Species: Lizards in an Evolutionary Tree

    Short Films

    (17 min 45 sec) This film explores the adaptation of anole lizards (genus Anolis) to habitats common across the islands of the Caribbean. The anoles are excellent examples of adaptive radiation, convergent evolution, and speciation through reproductive isolation.

  • The Making of the Fittest: The Birth and Death of Genes

    The Making of the Fittest: The Birth and Death of Genes

    Short Films

    (13 min 10 sec) Scientists have pieced together the evolutionary history of the Antarctic icefish. The icefish makes an excellent case study for genetic evolution as both the gain and loss of genes have led to key adaptations.

  • Regulation of Eukaryotic DNA Transcription

    Regulation of Eukaryotic DNA Transcription

    Animations

    (2 min 5 sec) General transcription factors, activators, and repressors interact to regulate the transcription of eukaryotic DNA into RNA.

  • The Chemical Structure of DNA

    The Chemical Structure of DNA

    Animations

    (2 min 44 sec) DNA's chemical properties can be harnessed for a variety of biotechnology applications.

  • Polymerase chain reaction (PCR)

    Polymerase chain reaction (PCR)

    Animations

    (54 sec) PCR is a standard laboratory technique that allows amplification of specific segments of DNA based on complementarity.

  • Learning from Mice: The Science of Transgenic Technology

    Learning from Mice: The Science of Transgenic Technology

    Clips

    (11 min 8 sec) 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.

  • Triplet code

    Triplet code

    Animations

    (1 min 8 sec) Once the structure of DNA was discovered, the next challenge was determining how the sequence of letters coded for the 20 amino acids. In theory, one or two letters can only code for 4 or 16 amino acids, respectively. A scheme using three letters, a triplet code, is the minimum necessary to encode for all the amino acids.

  • DNA Transcription (Advanced Detail)

    DNA Transcription (Advanced Detail)

    Animations

    (1 min 55 sec) This animation shows how RNA polymerase and other transcription factors interact to transcribe DNA into RNA.

  • DNA Transcription (Basic Detail)

    DNA Transcription (Basic Detail)

    Animations

    (1 min 55 sec) This animation shows the transcription of DNA into RNA.

  • Sickle Cell Anemia

    Sickle Cell Anemia

    Animations

    (1 min) Sickle cell anemia is a genetic disease that affects hemoglobin.

  • Shotgun sequencing

    Shotgun sequencing

    Animations

    (1 min) 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 sizes can be much larger than the small fragments.

  • Sanger method of DNA sequencing

    Sanger method of DNA sequencing

    Animations

    (52 sec) 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 DNA. These short DNA strands are ordered by size, and by reading the end letters from the shortest to the longest piece, the whole sequence of the original DNA is revealed.

  • DNA Replication (Advanced Detail)

    DNA Replication (Advanced Detail)

    Animations

    (2 min 20 sec) This animation shows the process of DNA replication, including details about how the mechanism differs between the leading and lagging strand.

  • DNA replication (basic detail)

    DNA replication (basic detail)

    Animations

    (1 min 7 sec) 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. Also available in Spanish.

  • DNA Replication (Schematic)

    DNA Replication (Schematic)

    Animations

    (50 sec) This animation shows a schematic representation of the mechanism of DNA replication.

  • Polymerase chain reaction

    Polymerase chain reaction

    Animations

    (1 min 28 sec) 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 can be made.

  • Paired DNA strands

    Paired DNA strands

    Animations

    (1 min 18 sec) 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 with G.

  • DNA packaging

    DNA packaging

    Animations

    (1 min 44 sec) DNA is tightly packed in the nucleus of every cell. DNA wraps around special proteins called histones, which form loops of DNA called nucleosomes. These nucleosomes coil and stack together to form fibers called chromatin. Chromatin in turn forms larger loops and coils to form chromosomes.

  • Human genome sequencing

    Human genome sequencing

    Animations

    (1 min 49 sec) The public Human Genome Project started by identifying unique marker sequences distributed throughout the genome. Then, many copies of a small section of DNA were randomly cleaved into smaller fragments, and each small fragment was sequenced. Because there were originally many copies of the DNA in question, many fragments represented the same part of the genome. These were aligned by identifying overlapping regions of the sequence, and then they were assembled into the original DNA.

  • Human chromosomes

    Human chromosomes

    Animations

    (47 sec) The human genome is organized into structures called chromosomes, consisting of 22 matching pairs and one pair of sex chromosomes.

  • Genetic engineering

    Genetic engineering

    Animations

    (1 min 13 sec) 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 engineered bacteria will now manufacture any protein coded by genes on the newly inserted DNA.

  • Damage to DNA leads to mutation

    Damage to DNA leads to mutation

    Animations

    (1 min 7 sec) Reactive molecules, such as free radicals, and solar ultraviolet radiation can lead to mutations in DNA. Most mutations are corrected, but in rare cases mutations can accumulate and cause diseases such as cancer.

  • Coding sequences in DNA

    Coding sequences in DNA

    Animations

    (1 min 5 sec) Of the 3 billion letters in the human genome, only 1% directly code for proteins. Of the rest, about 25% make up genes and their regulatory elements. The functions of the remaining letters are still unclear.

  • Chargaff's Ratio

    Chargaff's Ratio

    Animations

    (49 sec) In 1950, Erwin Chargaff published a paper stating that in the DNA of any given species, the ratio of adenine to thymine is equal, as is the ratio of cytosine to guanine. This became known as Chargaff's ratio, and it was an important clue for solving the structure of DNA.

  • Building blocks of DNA

    Building blocks of DNA

    Animations

    (27 sec) Adenine (A), cytosine (C), guanine (G), and thymine (T) are the components of nucleic acid that make up DNA.

  • MECP2

    MECP2

    Animations

    (43 sec) This animation shows how the protein MECP2, in conjuction with another protein complex, can act as an "on-off' switch for gene expression.

  • Mismatch Repair

    Mismatch Repair

    Animations

    (1 min 22 sec) This animation illustrates how mistakes made during DNA replication are repaired.

  • Tri Nucleotide Repeat

    Tri Nucleotide Repeat

    Animations

    (1 min 8 sec) Slippage during DNA replication can lead to expanding sections of repeating nucleotides. Watch this animation to see how this problem occurs. 

  • Meiosis

    Meiosis

    Animations

    (5 min 53 sec) This animation shows how meiosis, the form of cell division unique to egg and sperm production, can give rise to sperm that carry either an X or a Y chromosome.  

  • The Y Chromosome

    The Y Chromosome

    Animations

    (2 min 46 sec) The Y chromosome has been likened to a hall of mirrors because its sequence contains many sections that appear to be palindromes. These palindromes provide a clue to some interesting events that may have occurred during the course of the chromosome's evolution.

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