Cloning - Cloning Genes, Reproductive Cloning, Therapeutic Cloning, Opinions Shape Public Policy, Global Policies On Human Cloning
dna technology cell genome
The moral issues posed by human cloning are profound and have implications for today and for future generations. Today's overwhelming and bipartisan House action to prohibit human cloning is a strong ethical statement, which I commend. We must advance the promise and cause of science, but must do so in a way that honors and respects life.
—President George W. Bush
We must not say to millions of sick or injured human beings, "go ahead and die and stay paralyzed because we believe …a clump of cells is more important than you are."
—Representative Jerrold Nadler (D-NY)
The Human Genome Project defines three distinct types of cloning. The first is the use of highly specialized deoxyribonucleic acid (DNA) technology to produce multiple, exact copies of a single gene or other segment of DNA to obtain sufficient material to examine for research purposes. This process produces cloned collections of DNA known as clone libraries. The second kind of cloning involves the natural process of cell division to create identical copies of the entire cell. These copies are called a cell line. The third type of cloning, reproductive cloning, is the one that has received the most attention in the mass media. This is the process that generates complete, genetically identical organisms such as Dolly, the famous Scottish sheep cloned in 1996 and named after entertainer Dolly Parton.
Cloning may also be described by the technology used to perform it. For example, the term "recombinant DNA technology" describes the technology and mechanism of DNA cloning. Also known as molecular cloning, or gene cloning, it involves the transfer of a specific DNA fragment of interest to researchers from one organism to a self-replicating genetic element of another species such as a bacterial plasmid. (See Figure 8.1.) The DNA under study may then be reproduced in a host cell. This technology has been in use since the 1970s and is a standard practice in molecular biology laboratories.
Just as GenBank is an online public repository of the human genome sequence, the Clone Registry database is a sort of "public library." Used by genome sequencing centers to record which clones have been selected for sequencing, which sequencing efforts are currently underway, and which are finished and represented by sequence entries in GenBank, the Clone Registry may be freely accessed by scientists worldwide. To effectively coordinate all of this information, a standardized system of naming clones is essential. The nomenclature used is shown in Figure 8.2.