Sister chromatid exchange

SCE is elevated in pathologies including Bloom syndrome, having recombination rates ~10–100 times above normal, depending on cell type.

[3] Mitotic recombination in the budding yeast Saccharomyces cerevisiae is primarily a result of DNA repair processes responding to spontaneous or induced damages that occur during vegetative growth.

[6] The genomes of diploid organisms in natural populations are highly polymorphic for insertions and deletions.

[7] During oogenesis in the nematode Caenorhabditis elegans the sister chromatid, or even the same DNA molecule, can serve as a meiotic repair template for both crossover and non-crossover recombination.

For DNA double strand breaks induced throughout meiotic prophase I, the sister or intra-chromatid substrate is available as a recombinational repair partner.

Metaphase spread of a cell line showing a ring chromosome (R) and several non-sister chromatid exchanges (SCEs), some of which are indicated by arrows.
Scheme of a sister chromatid exchange. The ends of the chromatids are reversed in the lower area.