全新版大学英语综合教程第三册课件Unit 8

Kolata studied molecular biology as a graduate student at the Massachusetts Institute of Technology and received a master's degree in mathematics from the University of Maryland. She is a self-proclaimed exercise addict according to a Times advertisement for itself.
Background Information
Genetic Engineering
Narcissus
Genetic Engineering
Genetic engineering is the deliberate modification of the genetic make-up (genome) of an organism by manipulation of its DNA. Genetic engineering techniques include cell fusion and the use of recombinant DNA (rDNA). Since the late 1960s these techniques have held out the most exciting promise for biotechnology.
Genetic Engineering
In such a new field controversy inevitably abounds. Worries concerning release of genetically novel bacteria into the environment, or the possible manipulation of human embryos, have led to the setting up in the USA of the Genetic Manipulation Advisory Group (GMAG). Legislation governing genetic research has also been passed in several other countries.
Unit Six
Text A
A Clone is Born
Gina Kolata (born in Baltimore, Maryland, February 25, 1948) is a science journalist for The New York Times. Her sister was the environmental activist Judi Bari, and her mother was the mathematician Ruth Aaronson Bari.
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2. Cellular Cloning
Cloning a cell means to derive a population of cells from a single cell. In the case of unicellular organisms such as bacteria and yeast, this process is remarkably simple and essentially only requires the inoculation of the appropriate medium.
The term clone is derived from the Greek word for wig, branch, referring to the process whereby a new plant can be created from a twig. Cloning in biology is the process of producing populations of genetically-identical individuals that occurs in nature when organisms such as bacteria, insects or plants reproduce asexually. Cloning in biotechnology refers to processes used to create copies of DNA fragments cells, or organisms.
1. Molecular
CMolloecnulairncgloning refers to the
process of making multiple copies of a defined DNA sequence. Cloning is frequently used to amplify DNA fragments containing whole genes, but it can also be used to amplify any DNA sequence such as promoters, non-coding sequences and randomly fragmented DNA.
In practice, in order to amplify any DNA sequence in a living organism, that sequence must be linked to an origin of replication . However, a number of other features are needed and a variety of specialised cloning vectors exist that allow protein expression, single stranded RNA and DNA production and a host of other manipulations.