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Trinucleotide Repeat

Topic

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

Resource Type

  • Videos
  • Animations

Level

High School — AP/IBCollege

Duration

00:01:08
Favorited By
1 Users
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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

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

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