Another staining technique called comparative
genome hybridisation (CGH), which labels all chromosomes, has previously been used to analyse abnormalities in the polar body — a chromosome - containing sac expelled from the egg shortly after fertilisation.
A large variety of methods is used including genetic, molecular and cytogenetic techniques, fluorescence in situ
hybridisation and DNA «combing», as well as high throughput sequencing approaches such as DNA - seq for mutation landscape analyses, RNA - seq for transcriptome analyses and ChIP - seq mapping of chromatin - associated proteins and their
genome - wide modulation in response to DNA damages.