Replicação na presença de erros. Recombination at the Molecular Level Breakage and joining also...
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Transcript of Replicação na presença de erros. Recombination at the Molecular Level Breakage and joining also...
Recombination at the Molecular Level
• Breakage and joining also directed by enzymes.
• Homologous recombination occurs during synapsis in meiosis I, general recombination in bacteria, and viral genetic exchange.
• Molecular mechanism proposed by Holliday and Whitehouse (1964).
• Depends on complementary base pairing.
RecA protein-mediated DNA synapsisRec A has multiple DNA binding sites, hence can hold a single strand and a double helix together
Rec A is also a DNA-dependent ATPase
Replicative transposition – the element moves a copy of itself to a new site via a DNA intermediate
Conservative transposition – the element itself moves from the donor site into the target site
Retrotransposition – the element makes na RNA copy of itself which is reversed transcribed into a DNA which is then inserted
When IS elements get it together:composite transposons
Two IS elements flank an antibiotic resistance gene
Tn10 (E.coli)