Skip to main content
HHMI BioInteractive
  • Español
  • Site Search
  • Log In/Create Account
  • Classroom Resources
  • Teaching Tools
  • Professional Development
  • Partner Content

Trinucleotide Repeat

Topic

  • Biochemistry & Molecular Biology
  • DNA & RNA
  • Genetics
  • Genetic Disease

Resource Type

  • Videos
  • Animations

Level

High School — AP/IBCollege

Duration

00:01:08
Saved By
1 Users
Share This

Description

This animation shows how errors in DNA replication can lead to expanding sections of repeating nucleotides.

Some genes contain multiple repeats of three-nucleotide sequences, such as CAG. Increased numbers of these trinucleotide repeats are associated with several diseases, including Huntington’s disease and fragile X syndrome. As shown in the animation, trinucleotide repeats can expand due to slippage during DNA replication. The number of repeats can therefore increase with each cell division. Expanded repeats are also inherited and can grow longer over multiple generations.

This animation is a clip from a 2003 Holiday Lecture Series, Learning From Patients: The Science of Medicine. Depending on students’ background, it may be helpful to pause the animation at various points to discuss different structures or steps in the DNA replication process.

Key Terms

DNA replication, fragile X syndrome, hairpin loop, helicase, Huntington’s disease, mutation, nucleotide, polymerase

Terms of Use

Please see the Terms of Use for information on how this resource can be used.

Accessibility Level (WCAG compliance)

Video files meet criteria.

Version History

Date Published 02.04.03

Materials

Download Large (MOV) 11 MB
Download Large (WMV) 11 MB
Download Small (MOV) 4 MB
Download Small (WMV) 4 MB
Download Transcript (PDF) 10 KB

Use This Resource With

Interactive Media Resource
Interactive Video Builder

Explore Related Content

Other Related Resources

Showing of
Illustration of DNA transcription from the activity
Card Activities
“Fixing” Gene Expression
Computer image of DNA from the video
Animations
DNA Damage and Mutations
A circle containing round and sickle shapes; a couple are round with irregular edges.
Card Activities
Why Do Some People with the Sickle Cell Genotype Not Have Symptoms?
Computer illustration of p53 molecule
Click & Learn
The p53 Gene and Cancer
Illustration of RNA translation
Click & Learn
Central Dogma and Genetic Medicine
Image of the CRISPR Cas9 molecules from the interactive
Click & Learn
CRISPR-Cas9 Mechanism & Applications
Diagram of a DNA sequence on a sheet of paper
Animations
Human Chromosomes
Computer image of DNA unwound
Animations
Paired DNA Strands
Schematic image of DNA replicating from the video
Animations
DNA Replication (Schematic)
screenshot from the DNA replication animation showing helicase unwinding the double helix and the replication complex
Animations
DNA Replication (Basic Detail)
HHMI BioInteractive
  • About Us
  • Our Team
  • Our Advisors
  • FAQ
  • Contact Us
  • Facebook
  • Instagram
  • Twitter
  • YouTube
  • Newsletter Signup
  • HHMI.org
  • Terms of Use
  • Privacy Policy
  • Accessibility