ðə tɛknˈiːk jˈuːɾɪlˌaɪzᵻz ðə jˈuːɪd ɐ dʒˈiːn ʌv ˌɛʃɚɹˈɪkiə kˈoʊli, wˌɪtʃ kˈoʊdz fɚðɪ ˈɛnzaɪm, bˈeɪɾəɡlˈuːkjʊɹɹˌɑːnɪdˌeɪs; ðɪs ˈɛnzaɪm, wˌɛn ˈɪŋkjuːbˌeɪɾᵻd wɪð spəsˈɪfɪk kˈʌlɚləs ɔːɹ nˈɑːnflʊɹɹˈɛsənt sˈʌbstɹeɪts, kæn kənvˈɜːt ðˌɛm ˌɪntʊ stˈeɪbəl kˈʌlɚd ɔːɹ flʊɹɹˈɛsənt pɹˈɑːdʌkts.
The technique utilizes the uidA gene of Escherichia coli, which codes for the enzyme, β-glucuronidase; this enzyme, when incubated with specific colorless or non-fluorescent substrates, can convert them into stable colored or fluorescent products.