Manipulating DNA

Manipulating DNAThe Techniques Involved in Genetic

Engineering

Before we begin…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 EngineeringGenetic 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

InbreedingHybridization

Molecular manipulationInducing mutationsDNA splicing

Selective BreedingInbreeding

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 BreedingHybridization

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

Selective BreedingHybridization

In plants

Selective BreedingHybridization

In animals

Selective BreedingHybridization

In animals

Selective BreedingHybridization

In animals

Molecular ManipulationInducing mutation

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

Molecular ManipulationInducing mutation

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

Molecular ManipulationInducing mutation

Certain mutation causes oil-eating bacteria

Used to clean up oil spills!

Molecular ManipulationDNA 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 ManipulationDNA splicing

Extracting the DNA Getting the DNA out of the cell and separating it

from the other cell parts

Molecular ManipulationDNA 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 EnzymesA 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 EnzymesEcoR 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 AAA

A GGGC

C CT TTT

TGC

A AAA

A GGGC

C CT TTT

TGC

AA

AA

A GG G

C

CC

T T

TT

T

GC

A GGGC

C CTGCAT

GC

GC G

CGC

A GGGC

C CTGCAT

GC

GC G

CGC

A GCT

GC

GC

GGC

CGCATG

CGC

Molecular ManipulationDNA splicing

Pasting the DNA Using and enzyme called DNA ligase to attach

segments of DNA

Molecular ManipulationReal world application:

Analyzing DNAGel 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 DNAGel Electrophoresis