In the late 1800s, a scientist named Hans Driesch cloned a sea urchin by taking two cells of an embryo, placing them in a beaker of seawater and shaking it until the cells separated. Each cell formed a separate but identical sea urchin. In 1902, Hans Spemman used a human hair to separate two cells of a salamander embryo. Later, he also separated a single cell from a 16-cell embryo. In both cases, each separated embryo formed identical adult salamanders, totaling four – 2 of each original embryo. And, as is more widely known, in 1986 Ian Wilmut began a project to create a sheep that had a certain chemical in its milk. After 277 tries, on July 5, 1992, Dolly was born. In 2008, with great advances in technology, cloning and stem cell regeneration has become a very controversial issue.

A cell is the basic unit of life. All living things are made of them; they serve several functions, and are responsible for forming the tissues that make up an organism. Stem cells differ from other cells because they don’t have any tissue-specific structure or function. Stem cells also proliferate, or are able to replicate many times, unlike specialized cells (i.e. blood cells), and are capable of long-term self-renewal if they continue to replicate as unspecialized cells. Stem cells typically become the same type of tissue coinciding with the system in which they reside. When a stem cell goes through the process of becoming a specialized cell, it is differentiation.

Differentiation can be triggered by external sources (physical contact with specialized cells) or internal sources from DNA. Scientists are also experimenting with plasticity, or the ability to change one type of specialized cell into another within the same system, such as changing a blood-forming hematopoietic cell into muscular heart tissue. Being able to conduct these changes gives rise to cloning.

Cloning is creating an exact duplicate of a cell, which will eventually become an exact duplicate of the organism the original stem cell was taken from. There are three types of cloning: reproductive, therapeutic, and DNA. DNA cloning is the transfer of DNA fragments to a self-replicating genetic element. Scientists use this process to study bacterial plasmids, viruses, bacterial artificial chromosomes (BACs), and yeast artificial chromosomes (YACs). Plasmids are extra-chromosomal; self-replicating; and circular in structure, rather than the double-helix structure of DNA. Therapeutic cloning is the process of producing human embryos, and extracting the stem cells after the embryo has divided for only 5 days. It is not intended for human cloning.

Reproductive cloning is what scientists use to create a being that has the exact same nuclear DNA as an already-existing being. The scientists at the Office of Science with the United States Department of Energy states, “Recombinant DNA technology is important for learning about other related technologies, such as gene therapy, genetic engineering of organisms, and sequencing genomes. Gene therapy can be used to treat certain genetic conditions by introducing virus vectors that carry corrected copies of faulty genes into the cells of a host organism.

Genes from different organisms that improve taste and nutritional value or provide resistance to particular types of disease can be used to genetically engineer food crops. If the low success rates can be improved…reproductive cloning can be used to develop efficient ways to reliably reproduce animals with special qualities. For example, drug-producing animals or animals that have been genetically altered to serve as models for studying human disease could be mass-produced. Reproductive cloning also could be used to repopulate endangered animals or animals that are difficult to breed. Therapeutic cloning technology may some day be used in humans to produce whole organs from single cells or to produce healthy cells that can replace damaged cells in degenerative diseases such as Alzheimer’s or Parkinson’s.” (”Cloning Fact Sheet”) When the media talks about cloning, they are usually discussing reproductive cloning.