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Tài liệu tham khảo dành cho giáo viên, sinh viên, nghiên cứu sinh chuyên ngành sinh học - Công nghệ chuyển gen. | Gene Transfer Techniques in Plants by Nicole Jovanovic Have you ever wanted to make apples that repel worms Well you might be able to with today s transgenic technology. Today s transgenic technology involves gene transfer in plants as well as bacteria and animals. First of all to do genetic engineering you need a genetic vector. A genetic vector is something used to transport genes into the new host. There are a few things a vector needs to be a good vector. First a vector needs the DNA sequence that makes sure it gets copied when new cells are made. It also needs to have a way for new DNA to be inserted into it. Then it needs a reporter gene so scientists can tell whether or not the set of genes has made it into a cell or not. Finally it needs to be smaller than the new host s chromosome to get it through a plant cell s cell wall. This is where bacteria come into the picture. The reasons they are used are that they are easy to grow they are easy to manipulate their molecular biology is known they have lots of reporter genes and they have plasmids Purves 322 . The plasmid is a minichromosome for the bacterium as opposed to the main chromosome which is larger though both are rings Purves 267 322 . The plasmid has all four qualities mentioned above. The plasmid makes a good vector Purves 322 . You are probably wondering how new DNA is inserted into a plasmid. Well they are first cut into strips using chemicals called restriction enzymes Lurquin 44 . These chemicals cut DNA at special base pair sequences called recognition sites. EcoRI is a common restriction enzyme Lurquin 47 . When the DNA is cut tabs called sticky ends are left hanging and new DNA also with sticky ends is added and sealed with ligase Lurquin 47 Purves 322 . The result is called recombinant DNA. If you put recombinant DNA into a cell you will have transfected that cell. Once you have the new DNA you want in a plasmid you will need to find a way to get the plasmid back into a bacterium. One way to .
