ODM2 Variable Name Controlled Vocabulary ODM2 Working Group A vocabulary for describing the name of Variables. DNA damage, tail length In a single cell gel electrophoresis assay (comet assay), tail length is the distance of DNA migration from the body of the nuclear core Originally from the CUAHSI HIS VariableNameCV. See: http://his.cuahsi.org/mastercvreg/edit_cv11.aspx?tbl=VariableNameCV.