Polymerase Chain Reaction: If a small sample of DNA is collected, PCR can be used to amplify it. By using DNA polymerase, more copies of the target section can be made.

1. DNA is denatured2. Primers are annealed to the

start and end of the required section of DNA

3. DNA polymerase uses complementary base pairing to make more copies of the DNA

4.4 Genetic Engineering and Biotechnology

This cycle is repeated up to 35 times to yield sufficient DNA for lab use. PCR is often used to amplify a small sample found at a crime scene so it can be used as evidence in DNA profiling.

Gel Electrophoresis: 1. DNA sample is taken2. PCR amplifies DNA to

get a useful amount3. restriction enzymes

cut DNA into fragments of various lengths

4. samples are added to the wells at the origin end of the gel

5. smaller fragments move further down

Marker is used to show all of the possible DNA fragments. A tag can be added to bind to fragments at certain base sequences. This will glow under fluorescent light and gives a series of bands that can be compared as results of the DNA profile. DNA is negatively charged, so it travels from the negative electrode to the positive electrode.

Human Genome Project: An international collaborative effort to record the entire base sequence of the human genome. It was completed in April of 2003. The number and loci of all genes in our genome was found, which has led to targeted research in diagnostics, treatment, and pharmacology. Afterwards, bioinformatics was born. Many new proteins and their functions were discovered. Also, DNA comparisons can be made with other species and we can find out more about the evolutionary history of humans.

Bioinformatics: A way to collect and access information from genetic databases. By scanning a whole set of genetic markers, research and diagnosis can now be completed much more quickly.

The Human Genome Project: It has pushed forwards medical and pharmacological research by helping us to see the real cause. Many more diseases than we first thought are rooted in genetic causes, including lung cancer, obesity, and learning disabilities. By opening up the human genome and locating the genes which are at fault, it can be known which people are more at risk for certain conditions.

Bases: The genetic code is universal, and all living organisms use the same bases. This means that the base sequence can be transferred from one organism to another without changing their function. The bases are Thymine, Adenine, Guanine, and Cytosine. We could take the gene for healthy insulin production from a human and insert it into a bacterial plasmid. The bacteria will then be able to produce human insulin.

Recombinant DNA Technology: In gene transfer techniques, the gene for a favorable trait is identified in one organism and transferred to another. Gene transfer can be used to repair a faulty gene in an organism, to produce large volumes of a desired protein, and to genetically modify organisms for favorable characteristics.

Gene Transfer Steps: 1. Find a gene.2. Restriction enzyme cleaves

the desired DNA fragment.3. Take out the gene.4. DNA ligase inserts the gene

fragment into the plasmid.5. The modified plasmid is then

inserted into a host cell, which delivers the gene to the target cells.

Go to this link to see gene transfer in insulin production:http://www.abpischools.org.uk/res/coResourceImport/modules/hormones/en-flash/geneticeng.cfm

Electrophoresis Virtual Lab:

http://learn.genetics.utah.edu/content/labs/gel/

DNA Microarray Virtual Lab:

http://learn.genetics.utah.edu/content/labs/microarray/

Gene Therapy and SCID:SCID is Severe Combined Immunodeficiency. The lymphatic system fails to produce T-cells, which are essential for immune system function. It was once fatal to newborns which couldn’t fight infection, but there is early diagnosis and gene therapy to help with that. 1. Bone marrow is taken from the patient.2. The marrow is cultured with a virus that has been genetically modified to

carry the working version of the gene. 3. The virus inserts the gene into the chromosomes of the bone marrow stem

cells.4. In many of these cells, the gene will be inserted in the right position, and

these cells are returned to the patient’s bone marrow. 5. These reinserted cells serve as progenitor cells, which are templates for

building new, functional killer and helper T-cells.

Genetic Modification:Agriculture•Golden rice is enriched with beta-carotene, which can be converted into vitamin A in the body and can prevent blindness.

•Insecticide sweet-corn is resistant to pests so the farmer does not have to spray potentially harmful insecticides.

•Long-lasting, frost-resistant, or salt-resistant tomatoes, strawberries, etcetera are able to grow in harsher conditions or remain fresh longer for transportation and consumption.

Medicine and Research•Factor IX producing sheep produce human clotting factor in their milk, which is extracted and used to treat hemophiliacs.

•Glow in the dark pigs have been used in graft or transplant research to find out how far the donor cell DNA propagates in the recipient.

Ethics of Genetic Modification:The idea of genetically modified organisms is very controversial. Although there are great potential benefits of genetic engineering, people must be willing to accept responsibility for the possible risks. There are many benefits of genetic modification. Frost, flood, disease, or pest resistant crops can increase yields in countries with food shortages. This can help to improve both the local and national economy. Genetically modified organisms an be used to produce human proteins, such as insulin and clotting factor, to be used as medical treatments. Added nutrients, such as golden rice, an provide added nutrition n areas where food diversity is low. Human genes an be inserted into other species to allow research into pathology and treatment of genetic illnesses, which can help researchers to find cures.

Cloning: A clone is a group of genetically identical organisms or cells. The most commonly understood meaning of the term is the product of the transfer of a differentiated nucleus.

Cloning by transfer of a differentiated nucleus:1. Egg cell taken from donor. 2. Nucleus removed. 3. New nucleus fused with donor egg cell.4. Fused egg cell implanted into uterus of surrogate

mother.5. Surrogate mother carried fetus to term.6. Clone is born with DNA that is exactly the same as

the nuclear donor.

Therapeutic Cloning: It is the use of embryonic stem cells to produce healthy cells to be transplanted back into a patient.

Therapeutic Cloning Is:•the creation of a new egg cell using the DNA of a desired differentiated cell and a donor egg cell

•the creation of a human embryo through scientific means

•theoretically, this blastocyst could be implanted as in normal IVF and develop into a baby

Therapeutic Cloning Is Not:•it is not creating a mini-me for use in evil global domination plots or to create armies

•it is not creating a copy of a human to use as insurance in case you need a transplant

Ethics of Therapeutic Cloning:

Possible Benefits•rejection risk reduced in transplants

•no need to wait for human donor to die to give organs

•some success stories already reported in therapeutic cloning

Arguments Against•religious objections to “playing God” by creating what many consider to be human life

•UN recommendations against reproductive cloning are not ratified by all countries

•possible risk of a race to create the first human clone

(this is not reproductive cloning, cloning humans is illegal globally)

Induced Pluripotent Stem Cells:

http://www.nature.com/nature/journal/v453/n7193/box/nature07040_BX1.html