<p class="intro-text"> These parts collectively provide proof of concept for a semantic containment system that can prevent a horizontally transferred gene being read and expressed by any environmental cell that has picked it up. Our <a href="https://2018.igem.org/Team:Edinburgh_UG/Semantic_Containment_Modelling"> probability modelling </a> predicts that a gene that has 5 and 10 amber STOP codons substituted into the coding sequence will only be expressed 1 in every 10¹⁰ and 1 in every 10¹⁸ translation attempts. This is confirmed by growth curves for Top10 E. coli transformed with  <a href="http://parts.igem.org/Part:BBa_K2725012"> P1003 5* </a>  and  <a href="http://parts.igem.org/Part:BBa_K2725013"> P1003 10*.</a> No kanamycin resistance is observed from these strains. When P1003 5* is expressed alongside <a href="http://parts.igem.org/Part:BBa_K2725016"> J23108-supD </a> high level expression of the P1003 gene is achieved and confers kanamycin resistance in the strain. These parts together model a functional semantic containment system. </p>