1.
BIOTECHNOLOGY
2.
In broad terms, biotechnology is the manipulation of living organisms or their components
to perform practical tasks or provide useful products.
a. Biotechnology: any industrial or commercial use or alteration of organisms, cells,
or biological molecules to achieve specific practical goals.
3.
Four broad categories we will review:
a. DNA Recombination in nature and in the lab
b. Biotechnology and Forensics
c. Biotechnology and Agriculture
d. Biotechnology and Medicine
4.
Biotechnology allowed these men to be found innocent through the use of DNA
fingerprinting.
5.
Biotechnologies in agriculture make plants insect resistant.
6.
Biotechnology in medicine can help identify the causes of obesity.
7.
PREHISTORIC BIOTECHNOLOGY
a. Traditional applications of biotechnology include the use of yeast to produce beer and
wine in prehistoric civilizations in Egypt and the Near East.
b. People have selectively bred plants and animals for 10,000 years.
c. Selective breeding continues to be an important tool in biotechnology.
8.
BIOTECHNOLOGY TODAY
a. In addition to selective breeding, biotechnology uses genetic engineering.
b. GENETIC ENGINEERING: the modification of genetic material to achieve specific
goals.
c. The goals of genetic engineering include:
d. Learning about cellular processes; inheritance, gene expression. (You have done that
this term!)
e. Better understanding and treatment of diseases, especially genetic diseases.
f. Efficient production of biological molecules and improved plants and animals for
agriculture.
9.
A key tool in genetic engineering is recombinant DNA.
a. RECOMBINANT DNA: DNA that has been altered by the recombination of genes from a
different organism, typically from a different species.
b. Large amounts of recombinant DNA can be grown in bacteria, viruses, or yeast and
then transferred to other species.
10.
RECOMBINANT DNA
a. Plants and animals which express DNA that has been modified or derived from another
species are called:
b. Transgenic: Referring to an animal or plant that expresses DNA derived from another
species. An organism into which DNA from another species has been inserted.
c. GMOs: “Genetic Modified Organism” –an organism that has been produced through the
techniques of genetic engineering.
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11.
RECOMBINANT DNA
a. Most research labs involved in analysis of cell structure, genetics, molecular basis of
disease and evolution routinely use recombinant DNA technology.
b. One example: Since 1982, human insulin gene has been inserted into bacteria to
produce human insulin used in the treatment of diabetes and growth deficiency.
12.
DNA RECOMBINATION IN NATURE – natural recombinant DNA
a. TRANSFORMATION: a method of acquiring new genes, whereby DNA from one
bacterium (normally released after the death of the bacterium) becomes incorporated
into the DNA of another, living, bacterium. A phenomenon in which external genetic
material is assimilated by a cell.
13.
Transformation in Bacteria
a. Transformation enables bacteria to pick up DNA from the environment.
b. The DNA may be part of the chromosome from another bacterium or from another
species.
c. The DNA fragment is incorporated into bacterial chromosome.
14.
TRANSFORMATION in bacteria
a. Transformation may also occur when bacteria pick up tiny circular DNA molecules
called plasmids.
b. PLASMID: A small, circular piece of DNA located in the cytoplasm of many bacteria;
normally does not carry genes required for the normal functioning of the bacterium but
may carry genes that assist bacterial survival in certain environments, such as a gene
for antibiotic resistance.
15.
TRANSFORMATION in bacteria
a. Many types of bacteria contain plasmids ranging in size from 1000 to 100,000
nucleotides (ATCG) long.
b. Plasmids can be passed between bacteria and yeast – moving genes between a
prokaryotic and eukaryotic cell!
16.
Plasmids – Why Useful?
a. Plasmids (small rings of DNA) replicate in the cytoplasm of the bacterial cell.
b. Bacterium’s chromosome contains all of the genes necessary for basic survival, plasmid
not required for survival.
c. Plasmids: enhance a bacterium’s chance of survival. Some carry genes that enable
bacteria to grow in the presence of an antibiotic.
d. Researchers discovered that FOREIGN DNA PLACED INTO A PLASMID WILL
BECOME REPLICATED WITH THE PLASMID!
17.
VIRUSES TRANSFER GENES BETWEEN CELLS IN NATURE
a. Pictured: viruses that infect bacteria (bacteriophage).
b. Viruses transfer their genetic material into cells during infection.
c. Most viruses infect and replicate only in the cells of specific bacterial, animal or
plant species.
18.
VIRUSES Small Pox Virus pictured.
a. Viral DNA sequences become incorporated into one of the host cell’s
chromosomes.
b. The viral DNA may remain there for days, months, or even years.
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c. The cell replicates the incorporated viral DNA with its own DNA every time it
divides. This can lead to a “recombinant virus”.
19.
VIRUSES
a. When recombinant viruses infect new cells, they may also transfer a portion of the
previous host cells DNA to the new cell.
b. Viruses can cross species barriers.
c. These are examples of “genetic engineering” that occurs in nature.
20.
BIOTECHNOLOGY –TOOLS
a. In order to study genes, methods had to be developed to “purify” or isolate genes or
DNA for study.
b. A major tool of recombinant DNA technology was the discovery (1960’s) of a group of
bacterial enzymes called restriction enzymes.
c. These bacterial enzymes protected their cell by “cutting up” foreign DNA at particular
short nucleotide sequences.
21.
RESTRICTION ENZYMES
a. Restriction enzymes: An enzyme normally isolated from a bacterium that cuts doublestranded DNA at a specific nucleotide sequence; the nucleotide sequence that is cut
differs for different restriction enzymes.
22.
BIOTECHNOLOGY TOOLS: Vectors
a. Cloning Vectors: An agent used to transfer DNA in genetic engineering, such as a
plasmid that moves recombinant DNA from a test tube back into a cell, or a virus that
transfers recombinant DNA by infection.
b. DNA PROBES: a sequence of nucleotides that is complementary to the nucleotide
sequence in a gene under study; used to locate a given gene within a DNA library.
23.
DNA LIBRARIES
a. DNA LIBRARIES: a library is a collection of cells that host fragments of DNA from a
particular organism.
b. GENOMIC LIBRARY: a library that contains the organism’s entire set of genetic
material, or “genome”.
c. cDNA (complementary DNA) LIBRARY: is produced from mRNA’s, and represents only
genes that are expressed.
24.
BIOTECHNOLOGY: IMPORTANT METHODS
a. GEL ELECTROPHORESIS: Used to separate and identify segments of DNA. A
technique in which molecules (such as DNA fragments) are placed on restricted tracks
in a thin sheet of gelatinous material and exposed to an electrical field; the molecules
then migrate at a rate determined by certain characteristics, such as length.
25.
GEL ELECTROPHORESIS
a. DNA samples are pipetted into wells in a gel made of agarose
b. The gel has electrodes connected to each end. One electrode is made positive, one
negative; therefore, current will flow between the electrodes through the gel.
26.
GEL ELECTROPHORESIS
a. The phosphate groups in backbone of DNA are negatively charged.
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b. When the electrical current flows through the gel, the negatively charged DNA
molecules flow toward the positively charged electrode.
c. Smaller DNA molecules travel faster than larger.
d. Gel is placed on a special nylon paper. Electrical current drives DNA out of gel onto
nylon.
27.
GEL ELECTROPHORESIS
a. The DNA in the gel may form one continuous streak of every possible size of DNA
fragment.
b. Nylon paper with DNA is bathed in a solution of radioactive or fluorescent DNA probes
of the DNA segments of interest.
c. The probes base pair to the DNA and create bands that are labeled.
28.
GEL ELECTROPHORESIS:
a. Fluorescent dye identifies alleles or segments of DNA.
29.
BIOTECHNOLOGY – METHODS
a. DNA SEQUENCING: A method to determine the nucleotide sequence of a gene, a
segment of a gene, or the entire genome.
b. DNA sequencing is the gold standard for the study of DNA.
c. Developed by British scientist Frederick Sanger.
d. The method will copy DNA in a test tube using modified nucleotides that will block
further DNA synthesis.
30.
BIOTECHNOLOGY: IMPORTANT METHODS
31.
DNA FINGERPRINTING
32.
DNA FINGERPRINTING
a. As revealed in this DNA fingerprint, the DNA band created by the blood on the
defendant’s clothing matches the DNA bands of the victim’s blood.
b. The DNA bands from the defendant’s clothing do not match his own blood.
33.
Problems that must be solved before creating a DNA fingerprint:
a. What if there is only a small blood, tissue, or semen sample – not enough for testing?
b. What makes each person’s DNA so unique that THERE IS NO “reasonable doubt”
about which it belongs to?
c. ANSWER can be found with:
d. PCR, Kary B. Mullis, and short tandem repeats.
34.
INVENTION OF PCR
a. Once upon a time in 1986, there was a crazy scientist named Kary B. Mullis riding down
Pacific Coast Highway on his motorcycle (with his girlfriend) thinking about DNA.
b. “Why can’t we amplify (copy) unlimited amounts of DNA in the lab from a small
sample?” Kary Mullis asked himself.
c. The Polymerase Chain Reaction, which could copy large amounts of DNA from a small
sample, was invented.
d. This solved the problem of small DNA samples OR amplifying any gene of interest.
35.
SHORT, TANDEM REPEATS
a. Do human beings have DNA that is unique to just them? Would PCR copy them?
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b. STR’s: Short, tandem (side by side) repeats, STR’s, are repeating sequences of DNA
that are 2-5 nucleotides long each repeat. Each locus can have as few as 5-6 STR’s or
up to 14-15 copies.
c. STR’s are scattered throughout the human genome, found in “introns”, the part of the
DNA that does not “code” for proteins (only exons code for proteins).
d. STR’S and CRIME
36.
STR’S and CRIME
a. British and American law enforcement agencies agreed to a set of 10-13 STR’s, each 4
nucleotides long that vary greatly among individuals, to use to identify DNA fingerprints.
b. A perfect match of 10 STR’s in a suspect’s DNA and the DNA at the crime scene means
there is a less than one chance in a trillion that the two DNA samples did not come from
the person in question.
37.
POLYMERASE CHAIN REACTION
a. PCR Earned Mullis a part of the 1993 Nobel Prize for Chemistry.
b. PCR: a method of producing virtually unlimited numbers of copies of a specific piece of
DNA, starting with as little as one copy of the desired DNA.
c. With each cycle of PCR, the amount of DNA doubles.
38.
Crime investigators can now have ample supply of DNA to test with.
a. They label the STR’s with fluorescent dye or radioactive material, run the DNA on the
gel, and create a DNA fingerprint for suspect identification and possible conviction.
39.
EXAMPLES OF DIFFERENT STR’S IN DNA FINGERPRINTING
a. On far left and far right of each gel, the number of repeats represented by the band is
listed.
b. This gel demonstrates the STR samples of 13 different people.
c. D16 is an STR on chromosome 16.
40.
THOMAS BROCK
a. In 1966, Thomas Brock discovered Thermus aquaticus, a bacterium that lives in water
as hot as 80 degrees Celsius (176 degrees Fahrenheit) in the hot springs of
Yellowstone National Park.
41.
DNA FINGERPRINTING
a. All of these findings, along with restriction enzymes, electricity for gel electrophoresis,
and every other scientific discovery in regards to DNA technology made it possible for
these 2 men to go free.
42.
ADVANCEMENT OF DNA FINGERPRINTING TECHNIQUE
43.
BIOTECHNOLOGY AND AGRICULTURE
a. Many crops are produced using transgenic plants.
b. Farmers are interested in producing plants that are herbicide resistant and insect
resistant.
c. Genetically modifying plants requires the cloning of genes.
44.
CLONING A GENE:
a. 1. OBTAIN GENE
b. 2. INSERT INTO A PLASMID.
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c. HOW DO YOU OBTAIN A GENE?
d. ISOLATE THE GENE FROM DESIRED ORGANISM or SYNTHESIZE IN THE LAB.
e. WHY INSERT INTO A PLASMID?
45.
BIOTECHNOLOGY AND AGRICULTURE
a. Inserting a gene into a plasmid would be hopeless without the discovery of restriction
enzymes.
a. Both the gene from the bacterium and the gene of the plasmid are cut with the
same restriction enzyme.
b. Why? So they can reattach by complementary base-pairing.
46.
BIOTECHNOLOGY AND AGRICULTURE
a. The Bt gene (a gene that allows organism to resist insect attack) and a Ti Plasmid (likes
to put its genes in other chromosomes) are cut with the same restriction enzyme.
b. Mix gene and plasmid.
c. Transform bacteria.
d. Infect plant cell with transgenic bacteria.
e. Ti plasmid inserts its DNA (with Bt gene) into one of the plant cell’s chromosomes –
insect resistant plant!
47.
BIOTECHNOLOGY AND AGRICULTURE
a. It may be possible to engineer plants to produce human antibodies to combat various
diseases.
b. Transgenic animals are much more difficult to produce.
48.
DIFFERENCES BETWEEN TRADITIONAL AND MODERN
a. TRADITIONAL BIOTECHNOLOGY:
b. 1. Slow, many generations of selective breeding before new traits appear.
c. 2. Almost always combines genetic material from closely related species.
d. 3. Cannot manipulate the DNA sequence of genes.
e. MODERN BIOTECHNOLOGY:
f. 1. Massive genetic changes in a single generation.
g. 2. Able to recombine DNA from very different species in one organism.
h. 3. Can produce new genes never before seen on earth.
49.
BIOETHICS Benefits of Modern Technology
a. Herbicide resistant crops allow farmers to rid their fields of weeds which may reduce
harvests by 10% or more.
b. Insect resistant crops decrease the need to apply synthetic pesticides (savings of cost
of pesticide, fuel, labor).
c. Transgenic crops produce larger harvests at less cost.
50.
BIOETHICS Benefits of Modern Technology
a. Transgenic “Golden Rice” crops may bring hope to countries whose diets consist mostly
of rice, but lack Vitamin A, produced from the precursor beta-carotene.
b. Children in Asia, Africa, and Latin America die each year as a result of vitamin
deficiency, or become blind.
51.
BIOETHICS
a. Two principal scientific objections to the use of genetically modified organisms in
agriculture:
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b. Are they hazardous to human health?
c. Are they dangerous to the environment?
52.
BIOTECHNOLOGY in MEDICINE
a. Sickle Cell Anemia and Cystic Fibrosis carriers are identified by the use of modern day
biotechnology.
b. Restriction fragment length polymorphisms (RFLP’s) and RFLP analysis has become
the standard technique to diagnose sickle-cell anemia.
53.
RESTRICTION FRAGMENT LENGTH POLYMORPHISM (RFLP): a difference in the length
of restriction fragments, produced by cutting samples of DNA from different individuals of
the same species with the same set of restriction enzymes; the result of differences in
nucleotide sequences among individuals of the same species.
a. Restriction enzymes cut DNA into fragments that VARY in length.
b. Homologous chromosomes from the same person or from different people may differ in
lengths.
54.
BIOTECHNOLOGY in MEDICINE
a. SICKLE CELL ANEMIA – Simply stated:
b. A restriction enzyme (named Mst II) cuts a normal globin allele (the sickle cell gene) into
2 pieces, but cuts the sickle cell disease allele in 1 piece.
c. This creates one large band instead of two.
55.
CYSTIC FIBROSIS (CF) is an autosomal recessive disorder. It requires both homologous
chromosomes to carry a mutation.
a. CF has greater than 1200 mutations that have been known to cause disease.
b. 32 alleles account for 90% of the cases. RFLP analysis is not cost effective.
c. MICROARRAY OR DNA ARRAY TECHNOLOGY IS THE ANSWER.
56.
BIOTECHNOLOGY IN MEDICINE
a. Companies produce cystic fibrosis “arrays” which are pieces of specialized filter paper
to which segments of single stranded DNA are bound. Each piece of DNA is
complementary to a different one of the many cystic fibrosis alleles.
b. A patient’s DNA is cut into many small pieces, separated into single strands, and
labeled. The array is then bathed in the resulting solution of labeled DNA fragments.
Under the right conditions, only a perfect complementary strand of the person’s DNA
will bind to any given spot of DNA on the array.
c. Even a single wrong base will keep it from binding.
57.
GENE THERAPY
a. Genetic engineering has the potential to actually correct some genetic disorders.
b. It should be theoretically possible to replace or supplement the defective allele with a
functional, normal allele using recombinant DNA techniques.
58.
ETHICS OF BIOTECHNOLOGY Right or Wrong?
a. Some individuals believe biotechnology creates promise, other individuals believe it is a
threat.
b. In medicine, biotechnology is providing parents the information that could influence their
choice for a therapeutic abortion.
59.
BIOTECHNOLOGY AND MEDICINE
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