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Genetic Manipulation

Ever since man the hunter and gatherer gave up his nomadic way of life and began to tend stock and grow crops, he has been involved with genetic manipulation. Firstly, in ignorance simply by choosing to rear particular animals or plants, which were in some way advantageous to his developing lifestyle, and then much later as the science of Genetics began to develop, man has been engaged in breeding programmes designed to produce varieties of plants and animals exhibiting the specific characteristics which fit them to his various needs.

As man's exploitation of natural resources has continued and industries have developed based on the synthetic ability of micro­organisms, particularly the bacteria and fungi, his need for knowl­edge of the fundamental principles of the genetics of these organ­isms has increased and the new science of Molecular Genetics has emerged. The discipline seeks to understand the molecular base of inheritance and the way in which the information encoded by deoxy­ribonucleic acid (DNA) is utilized by the living cell.

Advances in the field of recombinant DNA research over the past decade have given the geneticist the techniques required to mobilize individual genes, that is specific sequences of DNA which code the amino acid structure of single proteins and transfer them from a donor to a recipient organism, thus conferring on the recipient the ability to synthesize the gene product. This is the practice of genetic manipulation as we understand the term today and which has become a cornerstone of the new Biotechnology. Now in addition to searching in nature for wild micro-organisms capable of producing specific products, a process which is often long and tedious and sometimes unrewarding, microbial hosts can be tailored for specific purposes by introducing foreign genes into them. The source of this foreign DNA can be microbial, animal, or plant and thus microbial hosts can be converted into biosynthetic factories capable of making a wide diversity of materials needed in every aspect of our lives from food and fuel to agriculture and medicine. As well as its potential in aspects of applied biology, recombinant DNA research is an extremely powerful tool for the elucidation of gene structure and function.

Most recombinant DNA experiments are designed to transfer specific genetic information from a donor organism to a recipient cell in such a way that the newly acquired gene will be expressed and result in the production of a "foreign" protein. In order to do this the DNA to be transferred must first be isolated from the donor organism and inserted into a DNA carrier or vector molecule which will be used to transfer it into its new host.

The ease with which fragments of DNA can be cut out of large DNA molecules, present in the chromosomes of plants and animals, and inserted into vectors has been assisted greatly by the discovery within the last 20 years of a group of enzymes known as restricted endonucleases. These enzymes recognize specific base sequences on DNA molecules and cut them precisely within or near that sequence. There are currently some three hundred of these enzymes known and some forty or so are commercially available in a highly-purified form.

The enormous growth of interest and input of capital into research­ing the applications of recombinant DNA research over the past decade is evidence of the potential benefit to man which these techniques can provide. Independent of its use for fundamental research in molecular genetics, a field which has provided and will continue to provide invaluable information to both academic and applied geneti­cists, recombinant DNA technology has already made important con­tributions in several areas of applied science.

1. Skimming

Read through the text and quote the exact words used by the author to define, explain or amplify the following:

(a) molecular genetics

(b) the practice of genetic manipulation

(c) individual genes

(d) a DNA carrier

(e) bacteria and fungi

(f) searching in nature for wild micro-organisms

2. Understanding the text: True or False?

Decide which of the statements are true, and which are not.

(a) The practice of genetic manipulation has a long history,

(b) The science of molecular genetics is relatively modern.

(c) Only wild micro-organisms can act as hosts to foreign DNA.

(d) Microbial hosts will not accept plant DNA.

(e) Research in recombinant DNA is valuable only to industry.

(f) In recombinant DNA experiments, DNA is transferred direct to the host from the donor.

(g) Enzymes are used to identify and isolate DNA transfer.

(h) There are 40 enzymes in the group known as restricted nu­cleases.

(i) A lot of time and money is being spent on research into recombinant DNA.

(j) Not much can be expected of genetic manipulation in the future.

3. Find in the text the following words and expressions and translate them into Russian

Present participle (verb + ing) describes what somebody or something is.

Ex. It was a fascinating story. (What kind of story? Fascinating.)

Past participle (verb + ed(for regular verbs)) describes how somebody feels.

Ex. We were fascinated by his story. ( How did we feel about his story? Fascinated.)

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