Genetic Engineering Overview
Genetic engineering seems to be one of the incredible breakthroughs in science. It was discovered in the 1900’s by Mendel, who used to study peas by creating different species at one time. Genetic engineering can be described as the non-natural alteration of the genetic code. Genes are parts of the DNA (deoxyribonucleic acid) that control the characteristics of individuals (e. g. hair colour); these are different for every individual. Normally genes are passed along generations but now scientists are now able to classify an individual gene and insert it into an organism that will carry the trait of that certain gene.
This organism is seen to be transgenic which is a term used to describe that the organisms DNA has been changed. Different genes from different organisms are able to be inserted into different species genes (e. g. a human gene can be placed in a bacteria gene). Genetic engineering is used for a number of different things. (Watson et al 1992) The typical genetic procedure goes as follows first the gene that will be taken has to be located and isolated. The messenger RNA from the gene needed has to be isolated and a simple complementary copy is done using an enzyme called transcriptase.
One more copy is made by adding another enzyme called polymerase, this creates a double stranded piece of DNA. DNA is a long strand and can be isolated from the mixture by precipitating it with ethanol. (Bill Indge et al 2000) The DNA is then suspended in a solution which contains a Ph buffer; the DNA is then cut using the restriction enzyme. The DNA parts are then inserted into a host. There are a number of ways in which this can be done the most common way is using viruses as vectors. The most frequent vector is bacterial plasmids.
A bacterium has two types of genetic material. There is a long strand of DNA in a form of a ring which is referred to a single circular chromosome. The second is a number of small rings of double stranded DNA called plasmids. These can be removed from the bacterium and inserted into a new bacterial cell quite easily. In the bacterium the plasmids are able to copy themselves. So any gene added to a plasmid is also copied, this is called cloning. (Bill Indge et al 2000) An isolated plasmid has to be cut open to be used as a vector using an enzyme, this causes ‘sticky ends’.
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The same restriction enzyme is used (the one that was used to cut out the DNA). These two are then joined together using an enzyme called ligase. This happens naturally in the nuclei, and it repairs any DNA that has been damaged in replication. Ligase then speeds both the complementary strand of DNA after the sticky ends of the strand have been joined. The genetically made plasmids are reinserted into the bacterium, where some of the recombinant plasmids enter the cytoplasm of the bacteria. (Bill Indge et al 2000) The first mammal to be cloned was a sheep called Dolly who was made by a ewe and ram mating.
She was an exact genetic replica of her donor a six year old female sheep. Sheep are just the start of animals being cloned. In Oregon they are cloning monkeys from embryonic cells. (www. science-education. nihHTML) A clone is an organism or cell that has been identically copied genetically to another cell or organism. Simple organisms like bacteria reproduce themselves by copying their own DNA and splitting. The two bacteria that come from this form asexual reproduction and are clones of each other as they are genetically the same.
The difference in sexual reproduction is that the nucleus of a sperm cell (this carries the father’s DNA) comes together with the nucleus of the egg cell (this contains the mother’s DNA). This gives the result of an offspring which contains genetic material from the mother and father, which means they are not identical to either of the parents. (www. science-education. nihHTML) Some animals are able to produce asexually, but mammals are unable to do this. This means we are unable to clone mammals naturally. Yet each cell has a complete set of genes, so this means in theory we are able to create a new animal from any cell or group of cells.
Only recently cells from very young embryos have revealed the ability to build up normally when separated. This occurs naturally when the cells in a two-cell embryo divide and develop without help to form identical twins. Some precious characteristics are worth prompting this procedure artificially. This can be used to boost the amount of calves that can be obtained from one generation by mating certain valuable parents. To increase the amount of calves produced means that also the number of eggs produced by the cow also has to be increase by number.
This is done by using follicle stimulating hormone (FSH). FSH stimulates the ovaries making them produce a few mature eggs at one particular time, not just the normal amount (which is using one or two). This is called superovulation, to become clones the cow needs to come from the same embryo. (Mike Bailey 2001) To make clones, the mature eggs are taken out and fertilised in special labs. When the eggs have grown into an embryo (8 or 16 cells), the cell nuclei are then divorced and transferred to an alternative cell.
This then grown into a new embryo, and is placed in the uterus of another cow. (Mike Bailey 2001) Most diabetics can’t make insulin so they need an external resource for this substance (this only applies to certain types of diabetics). Before human insulin was created diabetics had to inject themselves with either cow or pig insulin (this could occur as cow, pigs insulin are almost identical). But human insulin could be produced by genetic engineering. The human insulin is cloned into E coli (Escherchia coli) which is a bacteria cell. This bacterium divides about every 20 minutes.
The gene will be cloned in the total population (same gene in each single bacterial cell-million is copied so there is a copy of this gene within the population) this means that you can achieve many bacterial cells which are producing the human protein. Then the protein is able to be made in great amounts, isolated, purified, and then is give to the patients who need it. This has saved many lives to that fact that some people could not inject pig or cow insulin as they were allergic to it. (www. genetics. cjb. net) Humans have been ‘genetically modifying’ foods for many years but the way it has been done is by selective breeding.
This was done by choosing a plant and growing it. E. g. If you wanted your wheat plants to grow bigger in height. You would plant the seeds of the plant the seeds of the tall crops. Using tissue culture technique we are able to take plant cells and develop themselves into genetic modified plants. Rigorous testing is done before the genetically modified plant can be used for food production. Genetically modified plants are grown for a number of generations.
This is done to help make sure that the plants can retain and not lose what they have been set out to breed. www. vhihealthe. com) Not every type of genetic modified food plants or bacteria include the insertion of genes from a dissimilar species. Some GM crop plants can occur by ‘switching off’ certain genes that are involved in softening fruits. In these genetically modified plants the fruits will not soften quickly, making the damage and loss of fruits to a minimum. (www. vhihealthe. com) Further developments at the moment in genetically modified plants consist of the expression of the gene in certain sections of the plant, like in the leaves and roots.
This can be achieved by expressed just in parts of the plants by careful selection of the ‘switch’. (www. vhihealthe. com) There are many genes in the human genome. A genome is the total number of DNA in a cell. Some of these are codes for proteins, but about 95% of DNA is non-coding. About 40% of this DNA is made if short sequences of bases which are frequent repeated many times. Some of these sequences are dotted all through the DNA, but some are joined together in little clusters called tandem. These ‘tandem repeats’ are called satellite DNA and are hyper variable.
Each cluster of repeated DNA is known as a satellite. (Toole 1985) Genetic fingerprinting has help solve many crimes, and many people have been put way behind bars due to their actions. The technique of genetic fingerprinting has wide application in forensic, paternity and other relationship cases. The method depends upon a hybridisation between probes (short single-stranded DNA sequences) and single stranded DNA. Alec Jeffrey’s developed a method of analysis by which he could look at these sequences and observe differences between individuals in a population. These differences in DNA are known as polymorphisms.
DNA is extracted from samples of the individual to be tested. The DNA is then restricted and run on a gel. The resulting smear pattern that contains thousands of fragments varying in length, it is then transferred by blotting under alkaline conditions to ensure single-stranded ness to a nylon membrane. Once dried, the nylon is incubated with radioactively-labelled probes. The probes anneal to their complementary sequences in the smear on the membrane and binding sites appear as bands of sliver. These show positions of the sequence of interest in the smear of DNA. (Columgal. gov. uk)
Some people believe that genetic engineering will go too far and we will destroy or change all types of living things. Scientists could try to improve the human race by controlling the characteristics inherited, which goes against nature itself. Trying to do this could lead to severe combined immune deficiency (SCID) which could lead to death. Also tampering with an individual before it is bored could lead to problems with its development. Creating the most intelligent human could be very dangerous as people are now more likely to gain power using their minds instead of things like war.
Cloning could also been done to create copies of advice people like Hitler which could lead to danger to the whole world. (www. science-education. nihHTML) Genetic engineering is used in medicine which can be dangerous. Scientists who are trying to find a cure for a certain dieses can also intensify the risk of upgrading more harmful one. This could occur if a gene which will get rid of a disease can also make the disease stronger (as only the strongest will survive). Yet it is known that gene ties can be good for humans and other groups.
Another advantage to genetic engineering is that several diseases are now extinct as they have been wiped out. Some scientists are closer to finding a cure for ‘mucovicidose’ (it is a type of cancer) which is a very serious disease. Genetic engineering has also brought about finding a gene that is able to protect us from malaria. We are now also able to cure a deep burn by identifying a piece of skin that isn’t burnt and we cultivate and graft it. Also taking genetic engineering further could lead to help preventing a disease from happening at all.
We could also find a way of controlling and manipulating the genes that cause the certain disease. (www. genetics. cjb. net) Genetic engineering is used to modify foods which are made up of getting genes to make plants which humans are able to eat bigger in size. Most people don’t really want to eat these types of food as they believe that it is bad for their health. But this could help the third world countries improving their growth of food plants. Thanks to genetic engineering we are able to feed the worlds population, as animals can be more productive.
It has also improved the growing of crops by giving a greater yield for seeds to grow, lowering the need of fertilisers which has helped farmers cut on their costs. (www. genetics. cjb. net) Genetic modified crops (GMC) could discharge pollen or seeds from where they are growing and interact with non-GMC which can cause them to be genetically modified. This could then make a resistant to herbicides and make a group of ‘superweeds’. Another problem could also arise that transgenic organisms may tilt the balance between nature giving the result of severe repercussions.
Some could build up rapidly and compete for food with other organisms which will interfere with the sense of balance of nature. (Brian Tokar 2001) Some people belief that genetic fingerprinting is invading the privacy of our genetic information and can lead to discrimination, which is growing as we are learning more about human genes it, will be easier to screen for genetic diseases and mutations. As more and more genetic information is being stored in computer banks, the likelihood that unauthorised individuals will gain access to this data will increase, which again invades individuals privacy.
Yet there is also the point that many crimes have been solved thanks to the help of genetic fingerprinting. This has helped solve many serial rapes, serial killers, murders. Which met it prevented the loss of lives. (Brian Tokar 2001) Some religious people feel that genetic engineering is going too far and we are playing against god, as we are trying to control nature. Some religions do not draw on certain animals and believe that some animals are sacred (i. e. Hindus believe that cows are sacred animals).
Some people who believe in the Judaism faith believe that genetic engineering is acceptable. They thing that trying to solve the problems and correcting some abnormalities within a species is no different compared with putting right physical damages through surgery (i. e. heart surgery in humans). But the faith does draw lines to where the limit is. But most people who believe in the Hindu religion believe that this is a way of going against god’s way. Yet there are some people who believe that this information on genetic engineering has been given from god.
As if it wasn’t then genes would not have been created by god in the first place. They believe it has been give to stop the suffering of humans and animals. (www. genetics. cjb. net) There are also issues on the fact that animals are being tested in genetic engineering, the fact that animals are being used in these experiments. This can cause issues for human right groups. Is it fair that animals are being tested and kept in cages just to try and find out how to create the ‘perfect human’? Also that animal mutation is being formed because of this (a rat growing a human ear on its back).
But genetic engineering also has benefits to animals as endangered species are more likely to be saved from extinction due to cloning. (encyclopedia. infonautics. com) I believe that genetic engineering is a wonderful and powerful thing. But like all powerful things there are issues that occur. The main one is the miss-use of this technique which could result in the loss of lives or it cause problems for future generations. I believe that everyone should be informed about the benefits and consequences of genetic engineering. We should all be responsible of the developments and we should protect our planet and the living things on it.