I. MUTATIONS

Definition:

Any mistake or

change in the

sequence of DNA.

1. Types of MutationsA. Point Mutations

- A change in a single base pair.

Example:

Mr. Adoff is real cool! ATG TCA CGA

Mr. Adoff is _______? ATG TCA GGA

B. Frameshift Mutations

- A mutation which causes an entire shift in the genetic message.

Examples:

ATG ACG GCA TTG TCT GGA

Deletion: ATG AGG CAT TGT CTG GA_

ATG ACG GCA TTG TCT GGA

Insertion: ATG ACT GGC ATT GTC TGG A

- The entire protein sequence has been changed!

C. Chromosomal Mutations

- Affects large sections of DNA rather

than smaller sections.

- Portions of a chromosome (s) can be added, deleted or reversed.

Example:

Down Syndrome (Trisomy 21)

- Child has 47, instead of 46 chromosomes.

* What are some characteristics of someone with Trisomy 21?

Deletion

Duplication

Inversion

Translocation

Selective Breeding• Only allow organisms with desired traits to

breed with each other. – Ex- Dog breeding

• Hybridization- crossing dissimilar individuals to bring together the best traits of both.– Mule- cross between a donkey and horse

Selective Breeding cont.

• Inbreeding- continued breeding of ind. with similar characteristics. – Ex- different dog breeds– Can be dangerous due to increased chance

for genetic defects.

II. Genetic Engineering

Definition:

- Making changes to the DNA code of an organism.

How can I take a gene from one organism and insert it into another completely different organism?

A. Recombinant DNA

- DNA made by connecting fragments of DNA from different sources.

A + B = C

B. Restriction Enzymes

- Proteins which have the ability to “cut” pieces of DNA at specific base sequences.

Examples:

1. Hae III – Cuts DNA completely in half between every GGCC

sequence.

CATGGCCTATCCGG

GTACCGGATAGGCC

2. EcoRI – Cuts DNA after the G in every GAATTC sequence.

- Creates “sticky end” pieces of DNA. Recognition sequences

DNA Sequence

Restriction enzyme EcoRI cuts the DNA into fragments.

Sticky End

“Click image for animation.”

III. Applications for Genetic Engineering A. Creating Transgenic Organisms

What does “Transgenic” mean?- An organism that contains “functional”

recombinant DNA. Examples:

- Glowing Tobacco Plant- Mice with Human Immune System- Livestock with extra growth hormone

genes.- Insect Resistant corn and soybean- Over 90% of corn & 80% of soybean is a

hybrid.

B. Importance of Bacteria

- Bacteria are used to produce a variety of important substances for the health industry.

Examples:

- Insulin

- Human Growth Hormone

- Blood Clotting Factors

C. How are bacteria “Transformed?”

1. Bacteria contain a circular piece of DNA called a Plasmid.

2. A gene is removed from a human using restriction enzymes.

* The same restriction enzyme will be used to cut open the plasmid.

3. The human gene is inserted into the plasmid.

4. The bacteria will then reproduce quickly while producing the item coded for from the human piece of DNA.

IV. GEL ELECTROPHORESIS

- Process of separating DNA based on it’s size & charge.

- Each organic molecule will be attracted to either a positive or negative charge.

STEPS:

1. Cut DNA with restriction enzymes.

2. Place DNA in agarose gel and add buffer solution.

3. Turn on current and allow DNA pieces to separate. (DNA is negatively

charged.)

Click image for animation.

Polymerase Chain Reaction

• PCR is used by geneticists to make copies of DNA strands.

Cloning• A member of a population of genetically

identical cells produced from a single cell.