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What is Genetic Engineering?

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What is Genetic Engineering? Genetic engineering is an umbrella term which can cover a wide range of ways of changing the genetic material - the DNA code - in a living organism. This code contains all the information, stored in a long chain chemical molecule, which determines the nature of the organism - whether it is an amoeba, a pine tree, a robin, an octopus, a cow or a human being - and which characterises the particular individual. Apart from identical twins, your detailed genetic make-up is unique to you. Individual genes are particular sections of this chain, spaced out along it, which determine the characteristics and functions of our body. Defects of individual genes can cause a malfunction in the metabolism of the body, and are the roots of many "genetic" diseases. Genetic mapping Our understanding of our genetic makeup is being greatly expanded by a systemmatic mapping process known as the Human Genome Project, carried out internationally with enormous commercial and government funding. Smaller projects are also drawing the genetic map of pigs, chickens and some other organisms. As this work proceeds, individual genes are being identified for various functions and especially for medical conditions. Sometimes it appears that a single gene is responsible, for example in cystic fibrosis, but most conditions seem to be caused by more complex sets of factors, both genetic and environmental. We should make an important distinction between a gene which causes a condition outright, and one that gives one a susceptibilty to it, but which requires other factors to be present as well for the condition to develop. ...read more.


This is usually done by crossing two members of the same species which possess dominant alleles for particular genes, such as long life and quick metabolism in one organism crossed with another organism possessing genes for fast growth and high yield. Since both these organisms have dominant genes for these desirable characteristics, when they are crossed they will produce at least some offspring that will show ALL of these desirable characteristics. When such a cross occurs, the offspring is termed a hybrid, produced from two genetically dissimilar parents which usually produces offspring with more desirable qualities. Breeders continuously track which characteristics are possessed by each organism so when the breeding season comes once again, they can selectively breed the organisms to produce more favourable qualities in the offspring. The offspring will become heterozygous, meaning the allele for each characteristic will possess one dominant and one recessive gene. Most professional breeders have a true breeding cross (ie AAbb with AAbb) so that they will produce a gene bank of these qualities that can be crossed with aaBB to produce heterozygous offspring. This way the dominant features are retained in the first breeding group and can be passed on to offspring in the second instance. This process of selecting parents is called artificial selection or selective breeding, and poses no threat to nature from man manipulating the the course of nature. It has allowed our species to increase the efficiency of the animals and plants we breed, such as increasing milk yield from cows by continuously breeding selected cows with one another to produce a hybrid. ...read more.


It's a bit like moving on from a first-attempt demo music tape to a classic CD." The accurate genome sequence will allow researchers to identify genes involved in more complex diseases including cancer and diabetes. Professor Kay Davies, Department of Human Anatomy and Genetics, University of Oxford, said: "One of the great benefits to spring from the Human Genome Project is the full catalogue of genes, which gives us a clearer route to therapies. We now have a better navigating system. Using this, we have found genes that may compensate for the defect in muscular dystrophy using entirely novel methods, which could have implications for thousands of people." Before the sequencing project began it could take researchers months or even years to find one gene. Now the same task can be completed in hours or days. Professor William Cookson, Senior Clinical Fellow at the Welcome Trust Centre for Human Genetics, Oxford, said: "The completed sequence will greatly help in the mapping of disease genes from the unfinished chromosomes. Dealing with the fragmentary information provided by the draft was better than dealing with no information at all, but the finished sequence will make our lives as disease gene hunters much easier." In the last ten years, The Welcome Trust Sanger Institute has grown from 17 staff to 650 today and is a world leader, not only in sequencing DNA, but also in understanding the messages in our genes to improve human health. The achievement of a finished human genome sequence comes 50 years after James Watson and Francis Crick first elucidated the double-helical structure of DNA. ...read more.

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