Biotechnology

•  Gene: The unit of inherited information in DNA.

• Gene Splicing: Using restrictive enzymes to cut DNA and add new base pairs.

 • Recombinant DNA: Combining genes from

different sources—even different species—into a single DNA Molecule.

 

The Importance of Palindromes to

Genetic Engineers The sites where restriction enzymes cut the bacteria plasmid are called the restriction sites. Scientist recognizes these sites because they are palindromes.

For Example: 5’ A A T G G C C A T T 3’  3’ T T A C C G G T A A 5’ 

The Origins of Restriction Enzymes: Scientist obtain restriction enzymes from bacteria. In nature bacteria normally use these enzymes to restrict the invasion of foreign DNA, cutting the foreign DNA up into small, functionless pieces.

Function of Restriction Enzymes: Restriction enzymes are used as chemical “scissors” to cut out genes.

Ligase: An enzyme. The mechanism of DNA ligase is to form covalent phosphodiester bonds between 3' hydroxyl ends of one nucleotide with the 5' phosphate end of another. 

http://www.dnalc.org/ddnalc/resources/restriction.html

Genetic Engineering can be Harmful

•New Allergens in the Food Supply

•Antibiotic Resistance

•Production of New Toxins

•Concentration of Toxic Metals •Enhancement of the Environment for Toxic Fungi •Unknown Harms to Health

Genetic Engineering can be Helpful

•Increase in the Food Supply

•Production of insulin and other human hormones.

•Development of effective vaccines against disease causing microbes.

•Production of natural pesticides 

Antibiotics are used to detect the

transformed plasmids

Some plasmids carry resistance genes to several antibiotics.

The antibiotics that worked to select transformed bacteria

Ampacillin Resistance Tetracycline Resistance

Kanamycin Resistance

Proteins that are currently Produced using Genetic Engineering

Human Insulin Vaccines

Human Growth Hormone

Other Uses of Restrictive Enzymes

Disease Resistant Organism Insect Resistant Plants

Medical Research Larger Crops

Larger- Nutritionally Enhanced Food

Gene splicing is just what it sounds like: cutting the DNA of a gene to add base pairs. Contrary to the immediate image, however, no sharp instruments are involved; rather, everything is done chemically.

BioethicsThe study of ethical problems arising from scientific

advances, especially in the fields of biology and medicine.

Examples of Some Bioethical Issues

Assisted SuicideAbortion

Birth ControlGrowth Hormones – Performance Enhancement Drugs

In Vitro Fertilization Pre-Implantation Genetic Diagnosis

Genetic Modification – Genetic EngineeringCloning

Stem Cell Research

Pre-Implantation Diagnosis - PGD

Pre-Implantation Diagnosis - PGD

The pre-implantation genetic diagnosis (PGD) genetic testing procedure begins with in vitro fertilization. Embryos are formed in the lab, and then biopsied so cells can be used for genetic testing. The DNA codes of the diseases that PGD can screen for are then compared to the codes of each embryo. Only embryos with normal biopsy results free of genetic defects are used for implantation.

Diseases Detected with PGD Genetic Testing

Pre-implantation genetic diagnosis checks for genetic and chromosomal abnormalities that cause birth defects and miscarriage. This genetic testing procedure can identify recessive sex-linked disorders, dominant sex-linked disorders, single sex gene disorders, and chromosomal rearrangements.

Stem Cells

•Totipotent Cell: Formed during reproduction, a single cell (zygote: fertilzed egg) that divides to produce all the differentiated cells in an organism, including extraembryonic tissues.

•Pluripotent Cell: stem cell that has the potential to differentiate into any of the three germ layers: endoderm (interior stomach lining, gastrointestinal tract, the lungs), mesoderm (muscle, bone, blood, urogenital), or ectoderm (epidermal tissues and nervous system). Pluripotent stem cells can give rise to any fetal or adult cell type.

•Multipotent Cell: progenitor cells can give rise to several other cell types, but those types are limited in number. An example of a multipotent stem cell is a hematopoietic cell — a blood stem cell that can develop into several types of blood cells, but cannot develop into brain cells or other types of cells.

Unipotent Cell: Can give rise to only one type of cell.

Adult Stem Cells

Multipotent Cells

From Bone Marrow

Adult Stem CellsFrom Umbilical Cord

Embryonic Stem Cells

Stem Cell Development

1. Zygote: A fertilized egg.

2. Morula: A solid ball of 2-16 embryonic cells.

3. Blastula: A hollow ball of several hundred embronic cells.

4. Gastrula: Blastula pushes inward forming an inner embryonic cell layer.

5. Ectoderm: Outer embryonic cell layer. Skin, nervous system

6. Mesoderm : Middle embryonic cell layer. Muscle, bone.

7. Endoderm: Inner embronic cell layer. Digestive system.

Modeling Stem Cell Development

Zygote

1 Cell

Fertilized Egg

Before 3 Days

1-16 cells

Morula

3 - 14 Days

Several Hundred Cells

Blastula/Blastocyst

After 14 Days

Several hundred and More

Gastrula

• ECTODERM: Skin, Hair, Nails, Nervous System, Brain

• MESODERM: Muscles, Circulatory System, Excretory System, Bones, and Cartilage, Gonads

• ENDODERM: Digestive and Respiratory Tract, Glands including liver and pancreas,