Studying and Manipulating Genomes

polarbearfellowshipBiotechnology

Dec 12, 2012 (4 years and 8 months ago)

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Chapter 15

Studying and Manipulating
Genomes

15.1 Tinkering with the Molecules
of life


1953 James Watson and Francis Crick


1972 Paul Berg Recombinant DNA


1978 Allan Maxam, Walter Gilbert, Fred
Sanger develop methods for determining
Nucleotide sequences of cloned DNA
Fragments,


15.1 Tinkering with the Molecules
of life


Recombing DNA?

Frederick Griffith’s Experiment


1928, Tried to find a vaccine against
pneumonia.


Caused by a pneumococcus bacteria


Two types of bacteria:


Type S

or smooth covered capsule,


causes pneumonia



Type R

or rough covered capsule


Does not cause pneumonia



Type
-
S

bacteria

Type
-
R
bacteria

Heated
Type
-
S
bacteria

First

Step

Type
-
S

bacteria

Type
-
R
bacteria

Heated
Type
-
S
bacteria

Second

Step

Type
-
S

bacteria

Type
-
R
bacteria

Heated
Type
-
S
bacteria

Third

Step

Type
-
S

bacteria

Type
-
R
bacteria

Heated
Type
-
S
bacteria

Fourth

Step


The DNA Soap Opera”

by
Watson, Crick, Wilkins and Franklyn


1952: Kings College

X
-
ray crystallography


Died 1958

Watson and Crick

Won the 1962 noble prize in
science for their discovery”
the double helix”

15.1Genome / Genetic Code


All of the DNA in a haploid number of
chromosomes.


All of the DNA from each chromosome


A genetic code contains the information for
the sequence of amino acids in a particular
protein


This code is present in mRNA molecules
and is three bases long. This is known as a
codon


Ex
: UAG
-

is a codon

5.1 Human Genome Project


1988


NIH lead by Walter
Gilbert


Reassigned on Patent
issues



1993 replaced by
Francis Collins 1993



1998
-
2003 Craig
Venter, Celera
Genomics


Challenged US
government


99% accurate


21,000 genes identified


5.1 Human Genome Project


Videosaywhat?

15.2 Molecular Toolkit


Restriction enzyme: DNA scissors


Looks for specific 4
-
8 base pairs


Ex. EcoRI looks for GAATTC


Makes a fragment


DNA Ligase seals up



15.2 Genetic Engineering


Now that we understand genes we can change the
DNA of a cell.


The procedure for producing altered DNA is called
genetic engineering




Altered DNA is called
Recombinant DNA
.



Gene splicing

involves the breaking of a DNA
molecule and inserting or attaching new genes by
means of a chemical splice.

Plasmids



Are small DNA
fragments, are known
from almost all bacterial
cells.



Plasmids carry
between 2 and 30
genes. Some seem to
have the ability to move
in and out of the
bacterial chromosome


Recombinant DNA


Allows scientists to
insert the insulin gene
into bacterial plasmids.


The bacteria that contain
this gene produce
insulin, which is used by
people with diabetes.

What is Gene Splicing?


A dessert?

Gene Splicing

Transgenic mice:

Slicing jellyfish DNA in a mouse's
genome!!!

Superhero Gene Splicing

Gene Splicing

Gene Splicing

15.2 Genetic Engineering

Recombinant DNA

due to
Gene splicing



Medical


Human insulin producing bacteria


Human Growth Hormone
(HGH)

producing bacteria


Diabetic
-
donor corrective gene therapy


Agriculture and Forestry


Pest Resistant Crops (corn)


Antibiotic Rich Corn


HGH infused trout (live stock)


Inc Growth rate in trees and insect repellent trees (logging)





15.3



Gene library:


Probe: short stretch of DNA labeled radioactively


Nucleic Acid Hybridization:


Polymerase Chain Reaction (PCR): gene
replication



15.4 Separation Techniques


Chromatography
-
to make visible
pigments and extracts


Centrifuge
-
separates based on densities


Gel Electrophoresis
: Separates into DNA
fragments

15.4 Gel Electrophoresis


is a procedure for separating a mixture of
DNA molecules through a stationary
material (gel) in an electrical field.


15.5 Automated DNA
sequencing



15.6 Practical Genetics


Genetic Engineering


Genetic Engineering
-

is a new technology that
humans use to alter the genetic instructions in
organisms.




a)
Biotechnology
-

The application of
technology to biological science.





ex: removal of dinosaur DNA from a




mosquito’s last meal.




b)
Selective Breeding
-

A process that


produces domestic animals and new varieties

of plants with traits that are particularly

desirable.



DNA Technology


Makes it possible to put “new” genes into
organisms.


1. Human genes can be inserted into bacteria.


2. These altered bacteria become factories that
produce human protein.


ex: Gene Splicing


Recombinant DNA

Genetic Engineering and Therapies


Genetic engineering attempts to correct genetic
defects, alter foods , and fight diseases.


Gene therapy

replaces defective genes with
normal genes.


Gene splicing using
plasmids

(ring shaped
sections of bacterial DNA) can be used to create
desirable traits.

Selective Breeding,, easy stuff first

An Example of Selective Breeding







Brahman cattle:

Good resistance
to heat but poor
beef.







English
shorthorn cattle:
Good beef but
poor heat
resistance.






Santa Gertrudis
cattle: Formed
by crossing
Brahman and
English
shorthorns; has
good heat
resistance and
beef.

Gene Splicing

Transgenic mice:

Slicing jellyfish DNA in a mouse's
genome!!!

Cloning from Adult Vertebrate Cells



Cloning


A clone is a group of individual organisms that
have exactly the same genes.


Organisms that reproduce asexually produce
clones, since each offspring receives an exact
copy of the genes of the parent.



Dolly, 276 tries, 277= dolly

Cloning

Population Genetics


A
population

is a group of organisms of the
same species living together in the same
region (interbreeding).


Population genetics:

is the study of
changes in the genetic makeup of populations.


Gene Pool
:

The total of all the genes in a
population at any given time.

Population Genetics


Gene frequencies
:

how often (frequent)
a specific gene shows up in a population.

Population Genetics

The Hardy Weinberg Law
: Under certain
conditions the relative frequencies of alleles
for a given trait in a population do not
change. For this to be true:

1)
The population must be large

2)
Individuals must not migrate into or out of
the population.

3)
Mutations must not occur

4)
Reproduction must be completely random.

Cloning


Is a technique that accomplishes the same end result as asexual
reproduction.


It is a way of making identical genetic copies.


Cloning is done by inserting a nucleus from a “parent” organism’s
cell (one that has a complete set of genetic information from that
individual) into an egg cell from which the nucleus has been
removed. The result is an egg that now contains not 50%, but
100% of the genetic information from a single parent.


If this new egg cell with all of its genes can be made to develop
normally, the resulting offspring is a clone of the individual that
donated the original cell (In mammals, the egg would be implanted
and develop inside the body of the female).

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