Gene Technology• Karyotyping

• Genetic Engineering

• Genetic Engineering in Medicine & Society

• Genetic Engineering in Agriculture

Karyotyping: a picture of your chromosomes aligned according to size and shape starting with the longest one.

1. A karyotype is a specialized test that is done in a specific laboratory called a Cytogenetics lab.

2. Used to determine genetic diseases: Can see missing chromosomes or parts of chromosomes and added pieces of chromosomes or full chromosomes. You can also see defects in the chromosomes

3. In order to analyze chromosomes, the sample must contain cells that are actively dividing (in metaphase in mitosis)

Process of Making a Karyotype1. In order to study these disorders, cells from a person are grown with a

chemical that stops cell division at the metaphase stage

a. During metaphase, a chromosome exists as two chromatids

attached at the centromere.

2. The cells are stained to reveal banding patterns and placed on glass

slides.

3. The chromosomes are observed under the microscope, where

they are counted, checked for abnormalities, and photographed

4. The photograph is then enlarged, and the images of the chromosomes

are individually cut out.

5. The chromosomes are identified and arranged in homologous pairs.

1. Picture of chromosomes aligned together

Align according to size and banding patterns

http://learn.genetics.utah.edu/content/chromosomes/karyotype/http://learn.genetics.utah.edu/content/chromosomes/karyotype/

Genetic Engineering

• Manipulation of DNA for practical purposes

• Involves building RECOMBINANT DNA – from 2 or more different organisms

EX: Insulin – protein hormone regulates sugar metabolism – gene transferred to bacteria – transcribed/translated

Steps in Genetic Engineering

1 – DNA is cut

Restriction enzymes are bacterial enzymes that recognize and bind to specific short sequences of DNA, then cut the DNA between specific nucleotides within the sequences.

Vector – agent used to carry gene of interest into another cell - plasmid

2 – Recombinant DNA is produced

Enzyme – DNA ligase – added to help bond DNA fragments together

3 – Gene is cloned

Many copies of gene of interest are made each time host cell reproduces

4 – Cells are screened

Each time cell reproduces - it makes a copy of gene of interest – transcribes/translates

gene to make protein coded.

Genetic Engineering in Medicine & Society

• Medicines Clotting Factor VIII for Hemophilia

Growth FactorsInterleukins – HIV, cancer, immune issuesInterferons – viruses, cancerTaxol – ovarian cancer

• VaccinesSolution containing all /part of a harmless version of a pathogen – immune system recognizes pathogen’s surface proteins when injected – responds by making defensive proteins – antibodies – combats pathogen

Gene Therapy

• Technique that involves putting a healthy copy of a gene into the cells of a person whose copy of the gene is defective.

• Cells are removed from patient, healthy genes are inserted into cells, cells returned to patient’s body.

• Substance lacking is produced by cells with new genes• Examples: Cancer – Cystic Fibrosis

Hemophilia Rheumatoid arthritis

DNA Fingerprinting Gel Electrophoresis

Polymerase Chain Reaction (PCR)

• Needed to quickly make copies of DNA• Produce billions of DNA molecules fast!

Human Genome Project

• Chromosome map reveals locations of many genes• Improvements in diagnoses, treatments and

even cures for over 4000 genetic disorders

Genetic Engineering in Agriculture

• Crop Plants – improve favorable characteristics, yields, resistance to pests and herbicides (potatoes-soybeans-corn)

• Growth Hormone increases milk production – weight gain in livestock

• Risks?

Cloning

• Genetically identical • 1997 – Scientists announced the first successful cloning

using differentiated cells – a lamb named DOLLY!

Transgenic Animals

• Cloned and used to make

proteins that are

useful in medicine

Stem Cells• Adult (Somatic) Stem Cells;

• Adult stem cells are undifferentiated cells found throughout the body that divide to replenish dying cells and regenerate damaged tissues

• The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found.

a. Found in tissues/organs:

b. found in Bone marrow: can generate bone, cartilage,

fat, cells that support the formation of blood, and

fibrous connective tissue. Also form all blood cells

c. adult brain: generate the brain's three major cell

STEM CELLS

• Embryonic Stem Cells1. These cells form at the blastocyst stage of development. A

blastocyst is a hollow ball of cells that is smaller than a pinhead. The

embryonic stem cells lie within this ball of cells.2. The undifferentiated embryonic stem cells are next stimulated to

differentiate into the desired type of cell. They make nerve cells, heart cells, brain cells, muscle cells and other types of cells.

3. To produce differentiated cells the researchers modify the cells by inserting specific genes