Controversial Technologies: Genetic Engineering, Cloning, Gene Therapy, & Stem Cells

Question: If you had a population of animals, how would you increase the frequency of a certain trait in the population?

Selective Breeding Mate only the animals that have the trait you want offspring would have the desirable trait Example: cows Problems? Takes time (have to wait for animals to reproduce and the offspring to grow) Desirable trait may not show up in all offspring

Genetic Engineering Direct manipulation of an organism’s genome (DNA) via biotechnology Faster and more reliable way for increasing the frequency of a specific trait in a population Any organism who has had their DNA genetically engineered is known as a GMO (genetically modified organism)

Transgenic Organisms Organism that contains genes from other species

Transgenic Animals How is this rabbit transgenic? Makes a green fluorescent protein

Other examples…

Other examples…

Other examples…

What is wrong with this picture? Mouse is growing a human ear on its back

What is wrong with this picture? Chicken engineered without feathers

Involves: Cutting (cleaving) DNA from one organism into small fragments and inserting the fragments into a host organism of the same or different species.

Process of Genetic Engineering Step 1: Cut the DNA using Restriction enzymes

Each Restriction enzyme cuts the DNA at a specific nucleotide sequence Sticky Ends- Key to Recombinant DNA

Sticky ends between two different DNA sources join together to form Recombinant DNA.

Vectors are used to transfer DNA sequences from one organism into another. Mechanical- micropipette or gene gun Biological- viruses or plasmids

Is all genetic engineering bad? No, there are a lot of benefits to genetic engineering.

Transgenic Microorganisms Bacteria Produce human proteins for medical use (insulin, growth hormone, clotting factors) Done by inserting human gene into bacteria who produces compound quickly, cheaply and abundantly

In the future, bacteria may be used to… Produce materials for plastics Produce substances to fight cancer

Transgenic Animals Used to: Study genes Improve food supply Study effects of disease Increase the food supply Resistance to bacterial infections Produce human proteins

Transgenic Plants Increase food supply Produce natural insecticide Resistance to weed killing chemicals Resistance to rot and spoilage Produce human antibodies to fight disease Rice with Vitamin A

Is genetic engineering always a good thing? Can increase food supplies, produce better vaccines and medicines, and are possible cures for genetic disorders, but it is not always a good thing. can also be very harmful to humans through biochemical warfare and doing things like creating viruses that are indestructible.

Are genetically altered foods healthy? Absolutely! There is no proven downfall to eating genetically modified foods. Eating plants and animals that have been given growth hormones or other genes will not affect your health in any way.

Gene Therapy Use of DNA as a pharmaceutical agent to treat diseases How it works: DNA is inserted into cells to supplement or alter genes within an individual’s cells to treat diseases

Most commonly to treat/correct mutated genes Gene codes for a therapeutic protein drug (rather than a natural human gene) that encodes for nonfunctional protein in the individual Genes packaged in a vector that is used to get inside the cells of the body Once inside the cell, the cell expresses the DNA and produces the protein which treats the person’s disease

Cloning Clone- a member of a population of genetically identical cells produced from a single cell 1st clone- 1997 DOLLY

How Dolly was Cloned? A body cell is taken from a donor animal An egg cell is taken from a different animal The nucleus is removed from the egg Body cell and egg are fused by electric shock Fused cell begins dividing, becoming an embryo Embryo is implanted into the uterus of a foster mother The embryo develops into a cloned animal

Uses of Cloning Help save endangered species Make copies of transgenic organisms Technology is controversial Genetic defects & health problems in clones Serious ethical & moral issues

Gene Cloning Bacteria commonly used to clone (or produce identical copies) genes Plasmids inserted into the bacteria cell replicate separate from the bacterial chromosome Plasmids inserted into plant or animal cells are copied each time the cell divides (mitosis)

Stem Cells Primitive, undifferentiated cell that gives rise to other types of cells Can be used to replace diseased, damaged, or dead cells in the body that cannot repair themselves. It’s analogous to the concept of an organ transplant, except this time scientists are transplanting stem cells, not organs.

Stem cell characteristics The ability of differentiate into specialized cells. The ability to regenerate an infinite number of times. The ability to be relocated and differentiate where needed.

3 types of stem cells Totipotent Cells zygote has the genetic potential to create every cell of the body and the nourishing placenta and extra-embryonic tissues can form a human being This one totipotent cell divides into multiple totipotent cells for up to five days (three to four cellular divisions) after fertilization.

2. Pluripotent Cells (aka Embryonic Stem Cells): have the potential to create every cell of the body but not the necessary placenta and extra-embryonic tissues, cannot form a human being can be isolated from embryos as well as the sex cells of fetuses.

How it works:

3. Multipotent Cells: (aka adult stem cells) give rise to a limited number of other particular types of cells found in both developing fetuses and fully developed human beings

Limitations to Multipotent Cells have not identified multipotent cells for every type of mature body cell often in minute quantities and their numbers can decrease with age. take time to mature in culture in order to produce adequate amounts for treatment. Often contain DNA damage due to aging, sunlight (radiation), toxins, and random DNA mutation during replication.

Potential Uses of Pluripotent Stem Cells Regenetrate damaged organs fix organ donation shortage issue determine the specific causes of diseases (cannot always use animals to determine human causes of disease) can be used to do drug tests on instead of individuals Replace damaged cells in body