what are sister chromatid exchanges?

Answer 1

Sister chromatid exchange is the exchange of genetic material between two identical sister chromatids.
It was firstly discovered by using giemsa staining method on one chromatid belonging to the sister chromatid complex before anaphase in mitosis. The staining revealed that few segments were passed to the sister chromatid which was not dyed.
The reason for the s.c.e. is not known but it is required and used as a mutagenic testing of many prodpedia