In the second half of the twentieth century, the purpose of the DNA molecule was understood to be the molecule of life. Now, using recombinant DNA technology techniques, we can identify genes that we need from one organism and can put it together(recombine)the gene with another organism's genetic material. We can modify the genetic makeup of an organism by putting new "foreign" genes into an organism. Human genes can be inserted into bacteria. Bacteria have a round molecule of DNA called a plasmid. Using special restriction enzymes, we can cut open the plasmid at a particular location, leaving sticky ends on either side. We can then insert another species' gene using the same enzyme. The sticky ends fit to the gene that is being inserted almost like a molecular glue. Restriction enzymes are like "chemical scissors". When the bacteria go on to reproduce by fission, they pass the inserted gene along with the rest of their DNA to their offspring.They become "factories" to produce the gene product that the foreign gene codes for. For example, bacteria that are genetically modified with the human insulin gene, go on to produce human insulin which is beneficial for people with diabetes.