Transposons (“Jumping Genes”)

Transposons (“Jumping Genes”) explain structure types movement mechanism and role in gene regulation and mutation.

Definition of Transposons (“Jumping Genes”):

• Transposons are mobile genetic elements that can move within the genome, from one location to another, or between chromosomes and plasmids.

Types of Transposons:

1. Insertion Sequences (IS Elements):

   • The simplest transposons, containing only genes for transposase (an enzyme that catalyzes movement).
     • Example: IS1 in coli.

2. Composite Transposons:

   • Contain additional genes (e.g., antibiotic resistance genes) between two insertion sequences.
     • Example: Tn10 (carries tetracycline resistance).

3. Replicative Transposons:

   • Create a copy of themselves and insert it elsewhere in the genome.

4. Conjugative Transposons:

   • Can move between bacteria through conjugation and spread resistance genes.

Mechanism of Transposition:

• The transposase enzyme recognizes specific sequences and cuts the transposon out of its original location.
• The transposon is then inserted into a new location within the genome or a plasmid.

Significance of Transposons (“Jumping Genes”):

• Cause mutations by disrupting genes when they insert into new locations.
• Contribute to genetic variation and evolution.
• Help in the spread of antibiotic resistance genes among bacteria.

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