Basics of Human Gene Therapy

Basics of Human Gene Therapy

Wouldn't it be wonderful if there was no cancer? No heart disease? No blood problems? Everyone wants to be healthy and have a healthy family but some diseases are genetically related. How are these diseases avoided? This question was pondered by molecular biologists and geneticists. What they developed will revolutionize medicine and health care as we know it. The technique used to try to cure these "incurable" genetic diseases is called human gene therapy.

Gene therapy is by no means a new field of scientific query. The idea was first proposed back in the 1950's when Watson and Crick described a model of the double-stranded helix of DNA (Griffith 316). Knowing that DNA is composed of nucleotide base pairs in certain ways, scientists began to ask questions about the DNA structure in the 1970's (Becker) . If the bases can be arranged "incorrectly", then why can't they be rearranged in the "correct" way to produce the desired effect? Genetic experiments involving base pairing went on for years. After these years experiments with bacteria and viruses began. The genetic codes of these cells were changed to express different products like insulin. These products are human based but can be produced by non-human cells. This led to more thoughts and questions. If a bacteria cell can be altered to produce a human product, then why can't a human cell which can't produce this product be altered to produce it also? New experiments began with animals and creatures with larger genomes. Answers formed from the animal experiments. Technical advances occurred to the point that gene therapy could be performed on humans.

Gene therapy has now become a relatively simple process. The basics of the process are the identification of the gene in question, duplication of that gene, and insertion of the gene into the human genome needing the gene (CIS) . The gene that needs to be altered or replaced must be identified. The correctly functioning gene that replaces the defective gene must first be isolated and then duplicated. The gene in question can be isolated by attaching a molecular marker to the gene. The gene is then removed from the genome by a restriction enzyme that will break the genome only at the desired base junctions (i.e. when ATA is next to GAT). Genes removed from the genome can be duplicated easily by PCR. PCR is a process where the genetic sequence of the gene is replicated by the introduction of base pairs in the sequence along with replication enzymes, which induce, cause, and proofread replication.