Introduction
Transposable elements are also called jumping genes, or transposons.  They are a heterogeneous class of genetic elements that can insert at new locations on chromosomes. Transposons are classified into three major groups: Class I, retrotransposons; Class II, DNA transposons; Class III, miniature inverted-repeat transposable elements. 

Structure and mechanism of transposons
Transposons have direct repeat flanking sequences that are not part of the transposons, and terminal inverted repeats that are part of the transposons.  DNA transopsons translocate via a cut-and-paste mechanism, retrotransposons translocate via copy-and-paste mechanism.

Transposons in different organisms
Transposons exist in all organisms including bacteria.  Bacteria transposons include two related classes: IS and Tn elements, both of which are DNA transposons.  In Drosophila, P element is DNA transposon, while Copia and Gypsie are retrotransposons.  Maize has many different types of transposons, including Ac/Ds elements (DNA transposon) and MITEs.  Ty elements (retrotransposons) are well-studied in yeast. 

Genetic effect of transposons
Because they move around the genome, transposons cause significant changes in genome organization and gene sequence.  They can give insertion/deletion mutant and chromosomal inversion mutant.  Transposons are used as tools in gene delivery or targeted mutation.

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Transposable elements are also a heterogeneous class of genetic elements that can insert at new locations on chromosomes. They are classified into three major groups: Class I, retrotransposons; Class II, DNA transposons; and Class III, miniature inverted-repeat transposable elements.  Class I retrotransposon translocate via copy-and-paste mechanism, class II retrotransposon translocate via cut-and-paste mechanism, while the mechanism for MITEs are unknown.  Transposons cause chromosomal mutations such as deletion, insertion and inversion.  They are also used as tools for gene delivery and targeted gene mutation. 

• Concept map of transposons related to other types of DNA is given.
• Concept map of transposon types, mechanisms and structures.
• Detailed transposon structure including its flanking direct repeats and terminal inverted repeats
• Detailed diagram to show translocation mechanisms
• Thought-provoking questions for each section

Introduction

• Definitions
• Discovery of transposable elements

Types of transposable elements

• Types of retrotransposon
• LINEs
• SINEs
• Class II transposons
• MITEs

Structure and mechanism of transposons

• Direct repeat of retrotransposons
• Terminal inverted repeats
• Transposition of retrotransposons
• Transposition of class II transposons
• Replicative vs non-replicative transposons
• Regulation of transposition

Transposons in different organisms

• Transposons in Drosophila
• Transposons in maize
• Transposons in yeast
• Transposons in bacteria

Genetic effect of transposons

• Insertion/deletion mutant
• Inversion
• Gene delivery
• Transposon-tagging