Manipulating DNA

twoeggfinnishΒιοτεχνολογία

14 Δεκ 2012 (πριν από 4 χρόνια και 6 μήνες)

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The Techniques Involved in Genetic Engineering

In addition to the information in this presentation, you
should also be familiar with the corresponding
information found on pages
319
-
325

in your textbook

Genetic Engineering


Genetic engineering


Altering the genetic code of a living organism


in other words…



Changing the DNA of a living thing on purpose

The Changes…


Selective Breeding


Inbreeding


Hybridization



Molecular manipulation


Inducing mutations


DNA splicing


Selective Breeding


Inbreeding


The continued breeding of individuals with similar
characteristics

While inbreeding
does maintain the
characteristics of the
breed, it also makes
genetic defects more
common

Selective Breeding


Hybridization


The process of mating two organisms from different
species to create a
hybrid

Selective Breeding


Hybridization


In plants

Selective Breeding


Hybridization


In animals


Selective Breeding


Hybridization


In animals

Selective Breeding


Hybridization


In animals

Molecular Manipulation


Inducing mutation


Using artificial means (for example: radiation or drugs)
to cause specific mutations in living organisms

Molecular Manipulation


Inducing mutation


Certain mutation
causes extra
chromosomes leading
to bigger and stronger
fruiting plants

Molecular Manipulation


Inducing mutation


Certain mutation
causes oil
-
eating
bacteria


Used to clean up oil
spills!

Molecular Manipulation


DNA splicing


Taking a segment of DNA from one organism and
putting it into the DNA of another organism



Let’s go through the process…

Molecular Manipulation


DNA splicing


Extracting

the DNA


Getting the DNA out of the cell and separating it from the
other cell parts

Molecular Manipulation


DNA splicing


Cutting
the DNA


Whole DNA molecules are too large to be analyzed


Scientists cut them into smaller pieces using
restriction
enzymes

More on Restriction Enzymes


A
restriction enzyme

is a specialized enzyme that
cuts the DNA molecule at a very specific sequence



There are hundreds of restriction enzymes, each one
cutting the DNA at a specific sequence



Think of restriction enzymes like a
lock and key
: a
restriction enzyme will cut a DNA sequence only it
matches precisely

More on Restriction Enzymes

EcoR

I

SmaI


Cuts the DNA at the sequence
CTTAAG
, between the A and G


Cuts the DNA at the sequence
CCCGGG
, between the C and G

A

A

A

A

A

G

G

G

C

C

C

T

T

T

T

T

G

C

A

A

A

A

A

G

G

G

C

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C

T

T

T

T

T

G

C

A

A

A

A

A

G

G

G

C

C

C

T

T

T

T

T

G

C

A

G

G

G

C

C

C

T

G

C

A

T

G

C

G

C

G

C

G

C

A

G

G

G

C

C

C

T

G

C

A

T

G

C

G

C

G

C

G

C

A

G

C

T

G

C

G

C

G

G

C

C

G

C

A

T

G

C

G

C

Molecular Manipulation


DNA splicing


Pasting
the DNA


Using and enzyme called DNA
ligase

to attach segments of
DNA

Molecular Manipulation


Real world application:

Analyzing DNA


Gel Electrophoresis


DNA that has been cut with restriction enzymes is placed in
wells at one end of a porous gel


An electric voltage is applied to the gel, and the DNA which
has a (
-
) charge moves away from the (
-
) charge and toward
the (+) charge


The smaller the DNA particle, the farther it is able to move
through the porous gel



This allows scientists to compare the DNA sequences from
different individuals, or determine the relative sizes or
particular genes

Analyzing DNA

Gel

Electrophoresis