chapter 9

How is gel electrophoresis used? (examples)

forensics medical diagnostics paternity evolutionary relationships and more...

Dna fingerprinting can show relationships among....

family members

The setup of gel electrophoresis

-A sample of DNA is loaded into a gel, a thin slab of hard agarose. -A positive electrode is at one end and a negative electrode is at the other. -DNA is negative so the fragments move towards the positive pole.

Diseases that can be identified using genetic screening

-Cystic Fibrosis -Duchenne's Muscular Dystrophy -BRCA1 gene which has been linked to breast cancer

PCR uses 4 materials:

-DNA to be copied -DNA polymerase -Large amounts of nucleotide bases (A,T,C,G) -Two primers

What are some concerns about Genetic Engineering?

-GM foods could have negative side effects on our health (allergic reactions) -GM plants may negatively affect the environment EXAMPLE: Bt plants could kill insects that pollinate plants

What are some benefits that come with cloning?

-Organs from cloned mammals can be used for transplantation in humans. -Endangered species could be saved by using clones to increase the population.

What are some drawbacks associated with cloning?

-The success rate in cloning mammals is very low- it takes hundreds of attempts to produce one clone which is costly and time consuming. -Cloned animals have chromosomes that age prematurely making them more prone to disease as well as having problems in development and tend to become fatally oversized. -Cloned animals in the wild population would decrease diversity because the clones are all genetically identical.

What are some uses for recombinant DNA?

-To create crop plants that make medicines and vitamins, this process is called "pharming." -To make vaccines against HIV, the virus that causes AIDS.

what is gene knockout mice useful for

-studying gene function and genetic diseases because researchers can observe specific changes in gene expression and traits. -Often used to study obesity.

Each PCR cycle doubles the number of DNA copies, so after 30 cycles the original DNA sequence has been copied more than

1 billion times

methods by scientists to treat cancer with gene therapy

1. Inserting a gene that stimulates a person's immune system to attack cancer cells. 2. Insert "suicide" genes into cancer cells that activate a drug inside that kills only the cancer cells.

how are sequenced genomes used

1. The genomes of several plants have been sequenced to learn ways to improve crop yield and to increase crop resistance to disease and weather. 2. The genomes of rats and mice are similar to humans so they can be used as models for human diseases and gene function.

Human Genome Project goal

1. To map and sequence all of the DNA base pairs of the 46 human chromosomes 2. To identify all of the genes

clone

A genetically identical copy of a gene or of an organism

What was the first adult mammal cloned?

A sheep, named Dolly, in 1997.

How do restriction enzymes know where to cut the DNA?

An enzyme will recognize a 4-8 nucleotide sequence called a restriction site and cut within that region. There are hundreds of different restriction enzymes in a bacteria cell, each recognizes their own specific restriction site.

Examples of GM medicines

Anticoagulants, insulin, factor VIII

promotes blood clotting; Deficiency in Factor VIII leads to a type of hemophilia(blood disorder with no clotting system)

Factor VIII

Genetically modified medicines that are manufactured by genetic engineering.

GM medicines

an electrical current is used to separate a mixture of DNA fragments from each other.

Gel Electrophoresis

GM plants

Genetically engineered crops

Potential uses for stem cells:

Heart disease, leukemia, Rheumatiod arthritis, Parkinson's disease, diabetes, and could be used to grow new organs and repair spinal cord injuries

who cloned dolly?

Ian Wilmut

What was the traditional way that vaccines were prepared?

Killing a specific pathogen or making it unable to grow and then injecting it into the body

how can Genetic Engineers change plants

Make plants more tolerant to drought conditions and withstand frost, Create plants that can adapt to different soils, climates and environmental stresses, Add enzymes which control how fast fruit ripen. This improves shelf life, improve the nutritional value, Improve taste, and Make plants resistant to pests or insecticides.

why is the development of genetically engineered proteins important

Many genetic diseases/illnesses occur when the body fails to make critical proteins that are essential for proper functioning.

genetically engineered to always develop cancer (scientists mutated a gene that controls cell growth).

Oncomouse

what can be used to make a large sample of DNA even when there is a very small sample to start with

PCR

What are some examples of organisms that can clone themselves?

Plants can clone themselves from their roots Bacteria produce genetically identical copies through binary fission Sea stars can essentially clone themselves by the process of regeneration.

Examples of a vector

Plasmids, viruses, yeast.

what is the current method that uses gene therapy

Scientists have tried to take a sample of bone marrow stem cells and "infect" them with a virus that has been genetically engineered with a new gene. The stem cells are put back into the patients bone marrow where they will divide and make more blood cells with the gene.

3 steps of PCR

Separating, Binding, Copying

ethidium bromide binds to DNA fluoresces under UV light

Stain DNA

What is done with DNA after it is cut by restriction enzymes?

The DNA sequence of the gene can be studied; this is how we learn about different genetic disorders. A gene cut out of the DNA can be placed into the DNA of another organism. For example, the human insulin gene can be placed into bacteria to be copied. (Important for Diabetes) *Before any DNA procedure can occur, the DNA must be separated from each other. The fragments are sorted by size

How does making vaccines by genetic engineering avoid the traditional dangers (failure to kill or weaken the pathogen which could result in sickness.)

The genes that code for pathogen proteins are inserted into the DNA of a harmless bacteria and then injected into the body

an agent that is used to carry a gene of interest into another cell

Vector

how is the size of a DNA fragment determined?

a DNA fragment can be estimated by the distance it moves through the gel (smaller molecules travel more quickly and larger molecules travel slowly and appear at the top.)

Dna fingerprint

a representation of parts of DNA that can be used to identify a person at the molecular level

how do we learn about different genetic disorders.

after DNA is cut by restriction enzymes, the DNA sequence of the gene can be studied

Transgenic animals are much harder to produce than GM plants because

animals are more resistant to genetic manipulation.

proteins involved in dissolving blood clots; Effective in treating heart attack patients

anticoagulants

Where do restriction enzymes come from?

bacteria

restriction enzymes make cuts straight across the 2 strands of the molecule, leaving behind

blunt ends

Gene knockout mice

by disrupting the function of a gene it can be purposely "turned off."

how are the differences in the number of repeats found?

by separating the DNA fragments with gel electrophoresis

Researchers use the oncomouse to study

cancer and anticancer drugs

Dna fingerprints can be made with few

cells (thanks to PCR)

a DNA sample can become _________ if not handeled properly

contaminated (therefore it is harder to prove someone's guilt)

Polymerase Chain Reaction (PCR)

copies millions of a specific DNA sequence in a short time period.

restriction enzyme

enzyme that cuts DNA molecules at specific nucleotide sequences (found in bacteria)

genomics starts with

determining the order of DNA nucleotides in genes.(known as gene sequencing)

restriction map

diagram that shows the lengths of fragments between restriction sites in the strand of DNA (only indicate size, not DNA sequence; useful in genetic engineering; used to study mutations)

the replacement of a defective or missing gene, or the addition of a new gene , into a person's genome to treat a disease. (gene is delivered by a virus)

gene therapy

the changing of an organism's DNA to give the organism new traits.

genetic engineering

The process of testing a person's DNA to determine their risk of having or passing on a genetic disorder; Involves pedigree analysis and DNA testing

genetic screening

2 DNA segments with complementary sticky ends bases join together by what type of bond?

hydrogen bond

Most polymerases are broken down by excessive heat, so the polymerases used for PCR come from bacteria that live in

hydrothermal vents.

the greatest difference in DNA among people are found where?

in regions of the genome that are not part of the genes

Adult skin cells have been turned into pluripotent cells, which have similar potential to embryonic stem cells. These cells are called

induced Pluripotent Stem Cells (iPS).

treats diabetes (controls blood sugar levels)

insulin

the non coding regions known as

introns

If there are more repeats the DNA fragment will be

larger

restriction site

locations on a DNA molecule containing specific (4-8 base pairs in length) sequences of nucleotides, which are recognized by restriction enzymes.

DNA fingerprinting focuses on

noncoding regions of DNA, or DNA sequences outside of the genes

scientists have figured out a way to clone mammals using a process called

nuclear transfer

1. An unfertilized egg is taken from an animal and the egg's nucleus is removed. 2. A nucleus from the cell of the animal to be cloned is implanted into the egg. 3. Electricity is used to stimulate the egg so it will start dividing. 4. After the embryo grows for a few days it is transplanted

nuclear transfer steps

DNA fingerprints can also be used for

paternity tests and kinship tests necessary for immigration

closed tiny rings of DNA that are separate from the bacterial chromosome and can replicate on their own inside the cell.

plasmids

serve as good vectors.

plasmids

DNA that combines genes from more than one organism.

recombinant dna

The greatest difference in DNA among people are found in

regions that are not part of genes

enzymes that cut DNA molecules at specific nucleotide sequences

restriction enzyme

What purpose do restriction enzymes serve?

restriction enzymes protect the bacteria from viruses by cutting up the viral DNA

a dna fingerprint is a specific type of ___________

restriction map

Primer

short strand of DNA that acts as the starting point for a new strand.

in gel electrophoresis what kind of molecules move more quickly

smaller molecules

primers are needed because DNA polymerases can add complementary nucleotides to an existing strand they cannot...

start a strand

Pluripotent cells that can develop into any type of tissue

stem cells

1. A restriction enzyme is used to cut out the desired gene from a strand of DNA. 2. The same restriction enzyme is used to make cuts in the plasmid (or other vector). 3. The sticky ends of the opened plasmid base pair with the sticky ends of the gene. 4. The gene and plasmid are "glued" together using an enzyme called DNA ligase.

steps to make recombinant DNA

Other enzymes make staggered cuts leaving a portion of exposed bases called

sticky ends

Before any DNA procedure can occur......

the DNA must be separated from each other. The fragments are sorted by size.

Binding (step two of PCR)

the container is cooled allowing primers to bind to their complementary DNA sequences.

Copying (step three of PCR)

the container is heated again and the polymerases begin to build new strands of DNA.

Separating (step one of PCR)

the container with all of the reactants is heated to separate the double stranded DNA into single strands. (heat replaces DNA helicase)

Genetic Engineering is possible because

the genetic code is shared by all organisms.

after DNA is cut by restriction enzymes, a gene cut out of the DNA can be placed into the DNA of another organism. give an example of this.

the human insulin gene can be placed into bacteria to be copied. (important for diabetes)

each person's DNA differs in

the numbers of copies of the repeats

no individuals except identical twins can have

the same genetic material

Genomics

the study of genomes (all of an organism's genetic information)

what are transgenic animals used for

to produce human protein that is too complex to be made by bacteria or to create animals that can be used to model human development or disease.

Animals that have one or more genes from another organism inserted into their genome

transgenic animals

a solution containing all or part of a harmless version of a pathogen. ( any agent that causes disease)

vaccine