National institute of health - Sample Essay
Cloning is asexual reproduction this is when only one parents chromosomes are inherited. This is why they are genetically identical. Examples of organisms that reproduce asexually are 1. Single-celled organisms like archaea, bacteria 2. Many plants 3. Fungi reproduce asexually. There are different types of cloning, all with different cloning technologies and for different purposes; recombinant DNA technology or DNA cloning, reproductive cloning and therapeutic cloning. 4. 1 Recombinant DNA or DNA cloning DNA contains the genetic instruction to create an organism.
DNA has two strands which go parallel to each other; this is because of the nitrogenous bases that project inwards and takes the space between them. Diagram 1 on the right shows the structure of the DNA. DNA is the most important factor in cloning. The recombinant DNA technology is a technique for creating DNA molecules from unrelated organisms, ’. For example one of the DNA molecules is a bacterial or viral DNA, these are called cloning vectors. They have the ability to accept any other DNA molecule from an organism, which could be a human, monkey or bacterium, but often the bacterium E. Colli is used.
If you combine these two DNA molecules, it will allow replication of many copies of the DNA inserted into the cloning vector. Recombinant DNA technology has already been used to create identical copies of the same animals and to create entirely new species; like a GloFish, a type fish which glows a bright fluorescent coloring. Some types of cloning have improved many lives. One example is the production of insulin for diabetic people. According to the charity Diabetes UK, more than half a million people in the UK have the insulin dependent condition of diabetes. Method: 1. Step 1: Isolate the vector of DNA. 2.
Step 2: Select a piece of DNA to be inserted into a vector. 3. Step 3: Cut the piece of DNA with restriction enzyme and insert it into a test. tube, where they are able to join each other and form recombinant DNA. 4. Step 3: To link them permanently, enzyme DNA ligase is used. 5. Step 5: Insert the recombinant plasmid DNA into a host cell, where the vector and DNA is replicated and the plasmid will multiply copies of itself, in the cell. Other importance’s of Recombinant DNA are: Recombinant DNA will have an impact in all areas, here are a few: 1. Better crops (drought and heat resistance) 2. Recombinant vaccines like hepatitis B.
3. Prevention and cure of sickle cell anemia 4. Production of insulin 5. Cloning animals 6. Modified plants There haven’t been many ethical or moral issues surrounding DNA cloning and they more of a benefit then a threat. 4. 2 Therapeutic cloning There are many ethical issues related to stem cell research. Stem cells are cells which are unspecialized. They have two main properties: they are capable of differentiate into any type of other cell and to self-regenerate. Although we have stem cells in bone marrow these can only be specialized into certain specialized cells such as white blood cells. Different type of stem cells:
Embryonic stem cells-when a fertilized egg begins to divide which produces a group of stem cells called embryo. This embryo is basically early stem cells which is called a totipotent; stem cells that can turn into any type of cell. Blastocyst Embryonic stem cells-an embryo forms a hollow ball after 7 days of fertilization, this structure is called a Blastocyst. At the stage that the embryo is in Blastocyst stage it contains two types of cells: inner cell mass, which is formed by embryonic stem cells and eventually forms a fetus, and Trophoblast cells which forms a placenta on the outside of the ball eventually.
This provides the nutrients for the fetus. Pluripotent is the embryonic stem cells in the Blastocyst. The Pluripotent have the ability the change in almost most any kind of cell in the body. Fetal stem cells-an embryo is referred to a fetus after eight weeks of development of the embryo. By this stage the stem cells in the fetus are responsible to form the growth of all of the tissues before the birth. Fetal stem cells are also Pluripotent. Umbilical cord stem cells-after the birth of the baby, also contain stem cells which are genetically identical to the new born baby.
However the umbilical cord stem cells are Multipotent which can only differentiate into a limited variety of cell types. Also adult stem cells can sometimes not be used as they are already developed into tissues and are stem cells which are already directing their growth and maintenance during life. However embryonic stem cells-when a fertilized egg begins to divide, are very useful and can be specialized into any type of cell, this can solve many degenerative diseases.
But many people have strong feeling that this wrong due to religious reasons and tampering with nature, also some people find it cruel to destroy something that has the potential to live, even if it is for the greater good. We can see from the graph above that most people do agree with the fact that we should find cures and not delay things because of policies. Yet there are a significant proportion of people, who we cannot ignore, who believe that using embryos is wrong. There is still much controversy going on here and the question will still remain should we delay scientific advance that could save so many peoples lives or not.
I believe that only democracy can solve this problem. 4. 3 Reproductive cloning: Reproductive cloning is technique for producing an animal that has the same nuclear DNA as a previously existing animal. However some ethical issues arise from this which is: 1. There might be confusion in personal identity of the clone and the psychological effects 2. Some people believe that it will promote trends towards designer babies and human enhancement with side effects 3. Some people think that there will be ambiguous relations a cloned child and the progenitor 4. There might be technical and medical safety problems.
5. It is unnatural and undermines the concept of reproduction and having a family. An example of a reproductive clone is Dolly the sheep, which was created by using a cloning technology. They used a process called “somatic cell nuclear transfer”-SCNT- where an egg cell is used and the nucleus of the egg containing the DNA is removed and replaced by the DNA of another cell. The egg is then treated with chemicals or electrical current, so the egg is stimulated to divide and then transferred into the uterus of a suitable female host, until the birth of the offspring or clone.
Using the nuclear transfer technology, Dolly or any other animals created by using this chromosomal method, are not identical clones of the donor animals. The reason of this being is that the only thing that is the same between the clone and the donor is that of the nuclear DNA of the clone or the clones and the rest of the clone’s genetic material comes from the mitochondria in the cytoplasm of the enucleated egg. According to AVVS cloning of animals is wrong and their arguments are: 1. “Despite years of research, more than 95 percent of cloning attempts fail.
A significant number of cloned animals, as well as surrogate mothers who carry clone pregnancies, suffer serious and painful diseases and deformities to produce each ‘successful’ clone. ” 2. “Seemingly healthy cloned animals have been known to unexpectedly and suddenly develop health problems later in life. ” 3. “There is little rigorous scientific data available to make any claims about the health of the offspring of cloned animals, but the few studies that have been done indicate that these animals are weaker and less likely to survive than their conventional counterparts.
” 4. “Cloning increases the commodification of animals and promotes intensive farming practices, which negatively affect animal welfare at a time when consumers are increasingly demanding that farmed animals be treated more humanely. ” 5. “The FDA’s assessment of animal health risks was highly flawed and scientifically unsound. The government should not lift the moratorium on animal cloning until the animal welfare problems associated with cloning are thoroughly considered and properly addressed. ”