Genetic engineering (GE) is the direct modification of the organism genome through the application of advanced DNA technology. The modification of the genome of an organism is then reflected by the phenotypic traits which result from the modification (Greene 13). In genetic engineering, synthetic or foreign DNA is introduced into living organisms hence altering its genetic makeup (Cohen & Mary 80). This means that the arrangement of the genes within the chromosomes of the organism’s DNA are altered leading to different traits. The modern technology in DNA modification does not apply traditional genetic approaches however the classical breeding methods are applied in the propagation of the recombinant living organisms.
The traditional methods of genetic improvement were natural through the cross breeding plants and animals with different traits so that new traits are created within the offspring (Knoepffler 55). On the other hand, genetic engineering applies artificial methods in the alteration of living organisms’ genome so that desired qualities are created in the offspring. Recombinant DNA (rDNA) in genetic engineering is a result of genes combination from more than one origin to come up with a recombinant organism which is described as a genetically modified living organism (Anderson 20).
The history of genetic engineering dates back to 1973 when bacteria were genetically engineered through the introduction of rDNA into the bacteria by scientists. Scientific research continued in the area of genetic engineering which led to the modification of the multi-cellular organisms’ genome (Greene 13). For example, later in 1974 mice were also genetically modified. This illustrated the research growth in genetic engineering. This technology was aimed at producing organisms with biological advantages through artificial combination of various genes (Cohen and Mary 87). The offsprings which were created by genetic modification had advantages such as production of drugs and vital enzymes which were extracted and sold to manufacturing industries. For example the production of insulin producing bacteria in 1982 by scientists was highly commercialized. The field of genetic modification of organisms has grown significantly with time. As a result, genetically modified organisms (GMO) such as food have been introduced in the market since 1994 (Hammond 160).
The change in the genetic makeup of an organism in genetic engineering uses a set of technologies which involve manipulation of genes into chemicals considered biologically important. Genes determine the traits of an organism by acting as chemical blueprints specific for that organism hence genetic engineering leads to the combination of a number of traits which cannot be produced by natural means (Greene 13). This technology is different from the traditional natural animal and plant breeding because it involves introduction of new genes into unspecified points within the host genome. Moreover, genetic engineering is different from the natural methods of sexual production because there are no restrictions in the genetic combinations (Greene 13). For example, in natural breeding, cows are bred through breeding with other cows but genetic engineering may introduce desirable genes from anywhere in nature such as from sea urchins. This shows that genetic engineering has fewer limitations hence advantageous as compared to natural breeding. The application of genetic engineering is wide and includes various fields of research such as medicine and biotechnology (Anderson 22).
Types of Genetic Engineering
There are three major types of genetic engineering. Applied GE is a type of genetic modification which includes cloning and transgenesis. Chemical GE includes genes interaction, gene mapping and gene coding (Greene 12). The third type of genetic engineering is Analytical GE which involves computer modeling. Transgenesis is a type of applied genetic engineering where exogenous genes called transgenes are introduced into living organisms. The aim of this type of genetic modification is to cause organisms to exhibit new characteristics which are then passed to their offsprings (Knoepffler 57).
Gene interaction is a type of chemical genetic modification in which several different genes are collaborated with an aim of producing a single phenotype or related traits. This type of genetic engineering is commonly applied in the Mendelian experiments (Hammond 162). Gene mapping which is also known as a genome mapping is a type of chemical genetic engineering used to determine the sequence of certain features within the genome of a living organism. A genetic map is created using various markers on chromosome fragments. This type of genetic engineering is common in breeding experiments and pedigree analysis (Anderson 27).
Molecular cloning is usually done at the molecular level which has been practiced in scientific research as a method of creation of many identical genes or cells for biomedical studies. Each of the molecules and cells in the molecular cloning is similar to others. Molecular biologists have cloned DNA which is the molecular foundation of cells (Knoepffler 58). In molecular cloning, scientists copy and amplify fragments of DNA 2 which contain various genes into host cells which are normally bacteria. Molecular cloning promotes the scientific studies and experiments which require a large numbers of DNA molecules (Cohen & Mary 90). Molecular cloning is the basis for recombinant DNA technology which has been applied in the production of essential medicines. For example insulin was created using the molecular cloning and hence helped many diabetic patients.
In cellular cloning, cells which are derived from the body of a living organism are grown by scientists in a culture so that many copies of cells are created. The resultant cells are called cell lines and are similar to the original cells. This type of cloning procedure has also been applied in production of important medicines such as tissue plasminogen activator (TPA) which is used in treatment of heart attacks by dissolving clots (Hammond 164). Moreover, cellular cloning has been used in the insulin production. It is important to note that in both molecular and cellular cloning, germ cells (ova or sperms) are not involved. Hence these types of cloning are not able to produce a baby.
Embryo cloning is the cloning of animals and human beings which includes three categories: nuclear transfer, blastomere separation and blastocyst division. Nuclear transfer is the cloning technique which was used in cloning Dolly the sheep by the Roslin Institute (Hammond 167). In nuclear transfer, a nucleus is removed from each of the blastomeres of a four to eight cell embryo and transferred or transplanted into the egg from which the genome was removed. This is followed by artificial fusion of the membranes of the enucleated cell and the blastomere leading to the embryo development (Cohen and Mary 80). In blastomere separation, embryos are split immediately after fertilization. This is usually done at the two to eight cell stages where the blastomeres directed into production of multiple individual organisms have similar genetic composition. Blastomere separation is commonly applied in the breeding of livestock (Hammond 168). Blastocyst separation which is also called twinning is a form of embryo cloning where embryos are split into two similar halves after they have sexually formed. This is followed by transfer of the two halves into the uterus leading to the development of identical twins (Greene 13).
Cloning at the Roslin Institute
Nuclear transplantation was used in the Roslin Institute of Scotland to clone the first mammal from somatic cells of an adult. Dolly the Ssheep was born in July 15 1996 through nuclear somatic cell transfer in which a nucleus was transferred from a mammary cell of an adult sheep. The scientists induced fusion using electric pulses which enabled embryonic development of Dolly the sheep (Cohen and Mary 86). Therefore the success of cloning experiments in the Roslin Institute led to the increased interest of many scientists in the area of genetic engineering. Moreover, curiosity of many researches in genetic engineering has led to the need to genetically clone human beings. This has led to diverse opinions on the ethics of artificially creating human clones as opposed to the natural methods of reproduction.
Human cloning is simply defined as the creation of an indistinguishable copy of a human being through the use of modern genetic engineering technology. Human cloning also refers to artificial creation of human beings. It is therefore different from the natural reproduction of human tissues (Wilmut 16). Human clones are thus created as a result of human cloning and they appear as identical twins. Artificial cloning of cells, molecules, plants and animals leads to creation of genetically similar copies without the involvement of sexual process. Therefore human cloning is the asexual replication of human beings and it is usually possible at any point of development. In the modern biomedical research, human cells, genes, tissues and proteins are cloned with the aim of promoting human life (Knoepffler 59). As a result, this form of genetic engineering has raised several ethical issues which cause debates within the society.
The two major types of human cloning are the reproductive and therapeutic cloning. The creation of cloned human beings is a form of reproductive cloning while therapeutic cloning is the creation of human cells from an adult which are used in medicine (Hammond 168). There is also a theoretical possibility of human cloning referred to as replacement cloning which is a combination of reproductive and therapeutic cloning to replace damaged body cells as a way of recovery from a failing body which would be followed by partial or complete brain transplant (Greene 13). However, replacement cloning has not been possible but a lot of scientific research is currently focused in the area of genetic engineering.
Figure 1: Therapeutic Cloning
In November 1998, the first human clone was formed by the Advanced Cell Technologies (ACTs). This was a hybrid clone which was created from an egg of a cow and a cell from the leg of a man. The DNA from the cow’s egg were removed and fused with the human cell. The embryo which resulted would not be seen as human and thus was destroyed by the scientists after 12 days. The aim of this experiment was not reproductive cloning but rather it was aimed at therapeutic cloning (Cohen and Mary 85).
The second attempt to clone a human being was in January 2008 when the Stemagen Corporation Laboratory in California created five mature embryos. The scientists used genes from adult skin cells of a human being which were transferred to human ova. However the embryos were destroyed because the scientists said that it would be illegal and unethical if reproductive cloning was applied to create human beings (Hammond 162).
Advantages of Human Cloning
Human cloning which applies the somatic cell nuclear transfer can be applied in creation embryos which are to be used in research. The creation of embryos for research purposes is a process called therapeutic or research cloning (Greene 12). The aim of this process is to harvest stem cells from human clones which are used to study the embryonic development of human beings which can be used as a basis of providing treatment for various diseases. This application of cloning has enabled scientists and researchers to understand the cause of congenital diseases. As a result preventable measures have been taken to enable the protection of newborns from development of congenital deformities (Hammond 169).
Human cloning can be used in assisted reproduction which helps many patients by making pregnancies which would not otherwise have happened to be possible. The cloning technologies have been used in reproduction with minimal input of genomes from other parties. In vitro fertilization, donor sperm and ova in addition to surrogate motherhood have been made possible through artificial methods of assisted reproduction (Wilmut 17). There are circumstances when couples are not able to give birth especially in same sex marriages and when one of the parents is enable to provide the reproductive cells (Hammond 167). Therefore the application of cloning technology in assisted reproduction has assisted many couples in reproduction of human offsprings.
The cloning technology can be used to produce individuals with tissues which are immunologically similar to an existing being. This will assist in tissue donation (Wilmut 19). The transplantation of vital organs such as kidneys, liver heart has been a challenge in medical practice. This is due to incompatibility of human organs caused by differences in the genetic makeup among people. Many patients die as a result of failure to get a matching organ for the transplant (Knoepffler 60). This therefore justifies the use of cloning technology to produce the required donor organs and tissues. However there are ethical and legal issues associated with the use of cloning technology in the production of donor tissues which have resulted into many divergent opinions on this issue.
The cloning technology can be used to ensure healthy children. For example, parents who have a history of giving birth to children with Down syndrome would benefit from the scientific manipulation of the genome of the embryo before birth. This will lead to a healthy child and hence this demonstrates the advantages of the application of human cloning method (Hammond 169). Therefore the cloning technology would lead to the prevention of the birth defects especially those which result from genetic makeup of the offspring’s parents.
The proponents of the cloning technology suggest that research in this technology will lead to the reversing of the aging process through rejuvenation of cells (Wilmut 22). What is learned from cloning and the stem cell research will further lead to treatment of heart diseases. The researchers in the human cloning technology support the idea of using this technology to extend the lifespan of human beings which is usually the desire of many people.
The technology of human cloning can be applied in the reconstructive, plastic and cosmetic surgery. Plastic surgeons will thus be enabled to create bone, cartilage, fat and connective tissue which are identical to that of the patient and use it to reconstruct their features instead of the use of foreign objects. As a result, individuals are enabled to change their appearance without the risks such as the silicone gel leaks into the bodies of patients which are often experienced by plastic surgery patients (Knoepffler 70). Moreover, victims of accidents will be enabled to have the deformed features of their bodies satisfactorily repaired using the cloning technology which is relatively safer as compared to the modern reconstructive surgery methods.
Disadvantages of Human Cloning
The process of cloning results in the death of many newborns and embryos before any success is attained. For example, the Dolly experiment produced only 29 embryos out of the 277 fused eggs. Furthermore, out of the 23 sheep to which the embryos were transferred only one became pregnant with Dolly. This demonstrates the inhumanity and inefficiency of the experiments. The human cloning is thus considered unethical due to many deaths of embryos and newborns which characterize cloning experiments (Greene 13).
Cloning leads to the loss of diversity of human genes because human cloning usually copies identical genes. Therefore the diverse genes which are passed from parents to their offspring to enable the generations to have the power of adaptation will be lost through human cloning. The loss of the genes diversity will additionally lead to susceptibility of human beings to various diseases. Moreover, the beauty of human beings which is based on the differences in individuals will be lost through cloning which leads to the loss of diversity of the human genome (Hammond 160).
The inbreeding which characterizes human cloning is likely to lead to human extinction (Wilmut 25). This is due to the fact that cloning of human beings will result into same genotypes because people will keep on replicating among themselves. Moreover, the risks of genetic mutation which are associated with human cloning would result in abnormal babies. This is demonstrated by the disfigured creatures created in the animal cloning. Therefore the human abnormalities which would result from human cloning make the procedures unacceptable in many societies (Knoepffler 73).
There are many moral, ethical, political, religious and legal issues which concern human cloning. The legal situation of human cloning varies among different nations. Notable laws against cloning include those of Canada, Spain, Germany, the UK, Norway and Denmark. On the other hand, human cloning is not considered to be illegal in the US. However there are bans for federal funding in the area of cloning and embryo research in the United States. Such legal prohibition of human cloning demonstrates that the process is considered to be wrong by many societies (Greene 13). The religious opposition of human cloning, for example, asserts that it is a form of playing God. Moreover, the moral view of human cloning is that it is inhumane. The human clones which would be treated as property can be sold which is also considered immoral and unethical. Additionally, the opponents of cloning argue that there is a possible danger of abuse of the human cloning technology such as creation of human clones for military purposes which illustrate the unethical nature of technology (Hammond 162).
The application of genetic engineering in human cloning is likely to help in assisted reproduction, organ donation and production of healthy offspring, reversal of the aging process and in reconstructive surgery. However, the opponents of human cloning argue that it is unethical and may result in the loss of human diversity hence lead to human extinction. The research in stem cells has received opposition due to the use of the embryonic cells to create other cells hence pluripotent somatic cells are currently used by scientists. However, this research has received negative criticisms due to the ethical implications of the research findings application.