ɪt wʌz fˈɜːst dɪskˈʌvɚd baɪ jˈuːzɪŋ ðə dʒˈiːmsə stˈeɪnɪŋ mˈɛθəd ˌɔn wˈʌn kɹˈoʊmɐtˌɪd bᵻlˈɔŋɪŋ tə ðə sˈɪstɚ kɹˈoʊmɐtˌɪd kˈɑːmplɛks bᵻfˌoːɹ ˈænɐfˌeɪz ɪn maɪtˈoʊsɪs.
It was first discovered by using the Giemsa staining method on one chromatid belonging to the sister chromatid complex before anaphase in mitosis.