Genetic Engineering - New techniques, known collectively as genetic engineering , allow scientists to manipulate the genes of organisms

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11 Δεκ 2012 (πριν από 4 χρόνια και 10 μήνες)

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Genetic Engineering


New techniques, known collectively as
genetic engineering

, allow
scientists

to
mani
pulate the genes of organisms.


How are changes made?


Scientists use their knowledge of the structure of DNA and its chemical properties to
study an
d change the DNA molecule. Different techniques are used to extract DNA from
cells, to cut DNA into smaller pieces, to identify the sequence of bases in a DNA
molecule, and to make unlimited copied of DNA.


The Tools of Molecular Biology


Restriction enzy
mes


DNA molecules from most organisms are too large to be analyzed, scientists cut them
into smaller pieces by using restriction enzymes. A restriction enzyme cuts DNA at a
specific sequence of nucleotides.


Gel electrophoresis

Gel electrophoresis is a
procedure used to separate and analyze DNA fragments by
placing a mixture

of DNA fragments at one end of a porous gel and applying an electrical
voltage to the gel.

The smaller the DNA fragment the further it will move in the gel.


This procedure is used
to compare the genomes, or gene composition, of different
organisms or different individuals. It can also be used to identify or locate one particular
gene out of the tens of thousands of genes in an individual’s genome.


Recombinant DNA

Recombinant DNA i
s produced by combining DNA from different sources.


PCR (Polymerase Chain Reaction)

PCR is a technique that allows scientists to make many copies of a particular gene.


Genetic Markers

A genetic marker is a gene that that makes it possible to distinguish
bacteria that carry a
plasmid with foreign DNA from those that don’t.


DNA Fingerprinting

DNA fingerprinting is a procedure that analyses sections of DNA that have little or no
known function, but vary widely from one individual to another, in order to ide
ntify
individuals.