Genetic Mutations and Genetic Engineering - flickbio

roachavocadoBiotechnology

Dec 14, 2012 (4 years and 6 months ago)

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BIOTECHNOLOGY

The future is here!

MUTATIONS


Mutation

-

changes in the
DNA

sequence that affect genetic
information


Types of mutations:


Gene mutations

-

changes within a
single gene


Chromosomal mutations

-

changes
within a whole chromosome (affects
multiple genes)

Gene Mutations


Point Mutation
-

a change in
a single nucleotide (example:
changing an
A

to a
C
)


Frame
-
shift Mutation
-

an
insertion or deletion of a
nucleotide that causes a
different reading of codons
from the point of the change to
the end of the gene

Point Mutations


Normal

AAT TAA TAG GAT TTT AAA


Mutation

AAT TA
G

TAG GAT TTT AAA




The G was used instead
of an A.

Frame
-
Shift Mutations


Usually occurs as a result of an
insertion

or
deletion


Normal

TAC GCA TGG ATT


Insertion


TA
T

CGC ATG GAT T

T was inserted after the A.

Example using words:


THE FAT CAT ATE THE RAT



T
H
E FAT C AT A TE T HE R AT



TEF ATC ATA TET HER AT


Just like this mutated sentence does not
make sense, frameshift mutations make
nonsense proteins that cannot do their
jobs correctly.


DELETION of H

Chromosomal Mutations


Deletion


when part or all of a chromosome
is lost


Duplication


when part of a chromosome is
mistakenly repeated


Inversion


when part of a chromosome
becomes oriented in reverse of its normal
direction


Translocation


when one part of a
chromosome breaks off and attaches to
another nonhomologous (not the partner)
chromosome

Chromosomal Mutations

Deletion

Duplication

Inversion

Translocation

When do mutations occur?


During DNA replication, mistakes can be
made when DNA polymerase adds
complementary nucleotides.


If this mutation or mistake happens very early
on in a baby’s development, the mutation can
affect the entire baby. The rest of the cells
will have that same mutation.


Remember, we all start off as one cell that
must make many news cells through mitosis.
Every time your cells divide, DNA has to copy
itself and mistakes can be made.


If a one of your skin cells divides right
now and a mutation occurs, this is
probably not a problem.


However, if the mutation causes
certain genes to change, the new,
mutated skin cell can become a
cancer cell.


Cause of mutations


Mutagen



any agent that causes
DNA to mutate


UV light


Radiation


Smoking


Many different chemicals

Mutations gone wide


Cats

Gene Regulation


Only some of your genes are being
expressed (used to make protein) at any
given time.


Your body needs mechanisms to “turn
on” or “turn off” genes.


Chemicals can act as blocks or starters.


Some cancers are caused by genes
being turned on that should not have
been! For example, these genes can be
turned on by smoking, which mutates
DNA.

Types of Genetic Disorders


Autosomal

Dominant

gene


Example: Huntington’s Disease


Autosomal Recessive

gene


Examples: Tay Sachs, Sickle Cell Anemia, and
Albinism


Sex
-
linked Genes

(usually recessive)


Examples: Hemophilia and color
-
blindness


Chromosomal



entire chromosome or large areas
of a chromosome is affected


Random mutations


Example: Progeria

Genetic Engineering

Manipulating DNA

Working with DNA


DNA Extraction


Cells are chemically opened and
the DNA is pulled out.


Cutting DNA


DNA strands from most organisms
are much too large to be analyzed
all at once.


Somehow we must cut the DNA
into smaller fragments.


Special enzymes are used to cut
the DNA in specific places.


These special enzymes are called
restriction enzymes
.


These restriction enzymes cut the
DNA molecule at specific
sequences of nucleotides.


Recognition sequences

How do we separate the DNA
fragments?


ELECTROPHORESIS

Electrophor
-
what?!?


Electrophoresis is a technique that
separates DNA fragments (using
electricity) in a jello
-
like slab based on
the size of the fragments.


Smaller fragments are able to travel
longer distances more quickly.


DNA has a negative charge so the
fragments will flow toward the positive
electrode (opposites attract).

DNA plus
restriction
enzyme

Mixture of
DNA
fragments

Gel

Power
source


If you were to compare two
samples of the same DNA using
the same restriction enzymes, the
banding pattern would be the
same.


Different people make different
banding patterns.


And why would we do this?


DNA Fingerprinting


Paternity Tests


Children have a banding that is a
combination of their mom’s and dad’s
banding.


Crime solving


Identify the person who committed a crime
(no two people have the same DNA)


Medical diagnosis


Determine if you have the gene that
causes a disease or disorder.




Transgenic organisms


Transgenic organisms contain
genes from other organisms.


Genes from one organism can be
inserted into another organism.

Transgenic Bacteria


Used to make:


Insulin


Human Growth Hormone


Clotting Factors



Transgenic Animals


Used to study genes and improve
the food supply


Mice with human
-
like immune
systems.


Livestock with extra copies of
growth hormone genes.


Sheep and pigs that produce
human proteins in their milk.

Transgenic Plants


Used for food supply and medical
supplies


Soy and corn


Rice with additional Vitamin A


Plants that produce blood proteins

Cloning


Producing genetically identical
organisms from one original cell.


We have successfully cloned pigs,
cows, mice, sheep, and monkeys.


The first animal cloned was a sheep
named Dolly in 1997.

A donor cell is taken
from a sheep’s udder.

Donor
Nucleus

These two cells are
fused using an
electric shock.

Fused Cell

The fused cell
begins dividing
normally.

Embryo

The embryo is placed in
the uterus of a foster
mother.

Foster
Mother

The embryo develop
s
normally into a lamb

Dolly

Cloned Lamb

Egg Cell

An egg cell is taken from an adult
female sheep.

The nucleus of the
egg cell is removed.