How Does Cloning Work?

Cloning in the original sense of the word is the creation of genetically identical offspring during the process of asexual reproduction. This occurs in bacteria, insects and plants; humans have since developed the technology to artificially create genetically identical cells or individuals, and this is made use of in the field of biotechnology and genetics research.

The technique most commonly used to create clones is called somatic cell
nuclear transfer. This is the procedure that was used to create Dolly the sheep in 1997, the first animal to be successfully cloned. It involves the removal of the nucleus (containing the genetic material) from an egg, and its replacement with a nucleus from another adult cell, which can be from any tissue (for example a skin cell). The cells that fuse and form an embryo can then be transplanted into a suitable donor mother, and normal pregnancy proceeds. However, in most cases, isolated genes or cells are duplicated for scientific study, and no new animal results. Instead, stem cells can be extracted from the embryos, which are used to research potential treatments for a wide variety of diseases.
The problem with this technique is the low success rate of embryos that develop to full term. One American team who were attempting to clone primates used 15 000 eggs over the course of a decade in their attempts, and have only recently achieved success using a new technique called Oosight Spindle Imaging System which uses polarized light rather than dyes and ultraviolet light (believed to damage the cells) to visualization the microscopic cells in real-time. This breakthrough could make it easier to clone human embryos for use in research, with the aim of creating tissues which are genetically matched to patients and thus avoiding the risk of transplant rejection by the body's immune system. Research into therapeutic cloning could potentially provide a cure for degenerative diseases such as Parkinson's and diabetes.

Cloning in biology is the process of producing populations of genetically-identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments (molecular cloning), cells (cell cloning), or organisms.