What is a clone? A Clone is the name for a group of organisms or other living matter with exactly the same genetic material. Genetic material consists of genes, the parts of cells that determine characteristics in living things.
Many examples of clones exist in nature. In human beings and other higher animals, clones form naturally when identical twins or other genetically identical multiple births occur. Single-celled organisms, including bacteria, protozoa, and yeast, produce genetically identical offspring through asexual reproduction. These offspring develop from only one parent and are considered clones. Plants can also reproduce asexually through a process called vegetative propagation. In this process, a piece of root or stem can generate a new plant that is genetically identical to the donor plant. Vegetative propagation helps people obtain plant clones with desired traits. For example, farmers and breeders use this technique to develop apples with unique flavors or roses of certain colors.
Scientists produce many examples of clones in biological research laboratories. For instance, biologists can isolate individual cancer cells and enable them to reproduce to form cell colonies. These colonies consist of many clones of the original cancer cell. Laboratory scientists also develop clones of the chemical substance DNA (deoxyribonucleic acid). DNA occurs in every living cell and often contains thousands of genes. Scientists use DNA cloning techniques to reproduce specific genes. These techniques commonly involve plasmid DNA, which occurs in certain bacteria and can reproduce easily. Scientists first isolate a DNA fragment containing a particular gene. They then combine the DNA fragment with the plasmid DNA to form recombinant DNA. Because the plasmid DNA reproduces easily, the new recombinant DNA can also replicate easily. Thus, scientists can generate large quantities of the recombinant DNA and the particular gene of interest.
Cell cloning and DNA cloning have revolutionized the fields of biology and medicine. They have helped people acquire a better understanding of the structure and function of cells and genes. Cloning techniques enable scientists to better study defective genes in cancer cells and other mutant cells. Such studies, in turn, help us learn more about the function of these genes in normal cells. They also can help scientists discover the genetic causes of many diseases, thus enabling doctors to better diagnose and possibly cure these illnesses.
Using building material from cloned cow embryos, scientists say they have constructed miniature kidneys that appear to function similar to genuine organs (Haney, 1).
Improvements in cloning technology may yield important benefits to people. Cloning of such animals as cattle or sheep could enable scientists to create genetically superior livestock. These livestock would produce higher quality meat, milk, and wool. In the future, scientists may also be able to clone human beings. Human cloning could provide an effective way for infertile people to reproduce.
Peter Burbelo, "Clone," World Book Online Americas Edition,http://www.aolsvc.worldbook.aol.com/wbol/wbPage/na/ar/co/119610, February 10, 2002.
Scientists: Working Kidney Built From Embryo Clone
By DANIEL Q. HANEY
Science News; Washington; Oct 20, 2001; John Travis
Start Page: 250-252
Full Text: Copyright Science Service, Incorporated Oct 20, 2001