The final mRNA products in Eukaryotes are always short than the DNA sequence it was transcribed from due to introns splicing. If we take an eukaryote's gene, put in bacteria and expresses it, then the protein the bacteria makes will be different from the Eukaryote make. Because bacteria doesnt have splicing, so the RNA sequence will be longer, and as the result the protein will be different. So, how do we create functional Eukaryote's proteins using bacteria like insulin?