Nested DNA Inversion
In this form of phase variation. The promoter region of the genome can move from one copy of a gene to another through homologous recombination. This occurs with Campylobacter fetus surface proteins. The several different surface antigen proteins are all silent apart from one and all share a conserved region at the 5' end. The promoter sequence can then move between these conserved regions and allow expression of a different gene.
Read more about this topic: Phase Variation
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