DNA Repair

Spontaneous Alterations

Depurination and Deammination

Thymine Dimer

Deamintation

Depurination

Double-Strand Break Repair

DNA Recombination

Junction

ssDNA Hybridization

Rec A in Homologous Recombinaton at DNA

Synapsis

Holiday Junction

Resolving Holiday Junction

General Recombination in Mitotic and Meiotic Cells

Site Specific Recombination

• Moving of mobile genetic elements between non-homologous DNA

• Transpositional site-specific recombination– DNA only transposition

• Cut and Pase transposition• Replicative transposition

– Retroviral-like retrotransposition– Nonretroviral retrotransposition

• Conservative site-specific recombination

Bacterial Transposons

Cut-and-Paste Transposition

Replicative Transposon

Replicative Transposon

Retrovirus

Site-specific recombintaion by a retro virus or a retrovirus-like

retrotransposon

Nonretroviral Retrotransposon

Conservative site specific recombination