Chapter26

Classification

Taxon TIger Lion Gray WolfDomestic

CatMountain

Lion

Kingdom Animalia Animalia Animalia Animalia Animalia

Phylum Chordata Chordata Chordata Chordata Chordata

Class Mammalia Mammalia Mammalia Mammalia Mammalia

Order Carnivora Carnivora Carnivora Carnivora Carnivora

Family Felidae X Canidae Felidae Felidae

Genus Panthera Panthera Canis Felis Puma

SpeciesPanthera

tigrisPanthera leo Canis lupus Felis catus

Puma Concolor

• What is the scientific name of a gray wolf?• Which taxon includes the broadest characteristics?• Which taxon includes the most specific

characteristics?• Which taxa do they all have in common?• Which taxon can interbreed and produce fertile

offspring?• In the lion column, what name would you put instead

of the X?• Which organisms in the chart is most closely related to

Panthera Onca?• The red fox classification is Animalia, Chordata,

mammalia, Carnivora, Canidae, Vulpus, Vulpus vulpus. Is more related to a dog or big cat?

Chapter 26Biotechnology and Genomics

1. DNA CloningFirst of all, what is the difference between

gene cloning and cloning?• Cloning

– Production of identical copies of an organism through asexual means

• Gene cloning– Production of many identical copies of a single

gene

A. Uses of gene cloning– Might want to produce large quantities of the

gene’s protein product

– Learn how a cloned gene codes for a particular protein

– Use the genes to alter the phenotypes of other organisms in a beneficial way

• Produces transgenic organism• Gene therapy - cloned genes are used to modify a

human

Figure 12.2

Example: Making HumulinIn 1982, the world’s first genetically engineered pharmaceutical product was produced.

• Humulin, human insulin, was produced by genetically modified bacteria.

B. Polymerase chain reaction (PCR)

Create billions of copies of a segment of DNA in a test tube in a matter of hours

–Amplifies targeted DNA sequence–Needs:

• Your DNA sample• DNA polymerase (the enzyme involved in DNA

replication)• a supply of DNA nucleotides

Figure 12.14

So a lot of DNA can be made from a tiny bit of DNA sample, such as a tiny blood sample taken from a crime scene

2. DNA analysisDNA fingerprint

1. The DNA is cut into fragmentsSpecific enzymes called restriction enzymes recognizes

specific small DNA sequences and cut the DNA.

2. Fragments separated by gel electrophoresis

Smaller fragments move faster than larger fragments

3. Results in distinctive pattern of bands

How does gel electrophoresis work?DNA has negative charges, so it will migrate towards the positive charge

Long fragments(move slower)

Shorter fragments (Move Faster)

-

+

Use of DNA fingerprintingMurder, Paternity, and Ancient DNA

DNA fingerprinting – Has become a standard criminology tool.– Has been used to identify victims of the

September 11, 2001, World Trade Center attack.

– Can be used in paternity cases.– To study ancient pieces of DNA, such as that

of Cheddar Man.– And the list goes on…

Figure 12.12

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Mother Child Male 1 Male 2

few

many

DNA Band patterns

Figure 12.13

Cheddar Man

• Oldest complete skeleton found in Britain.

• 9 000 year old

• Compared his DNA with a number of living resident from Cheddar village and found some matching, suggesting that they share a common ancestor with the Cheddar man.

3. Biotechnology Products

• Transgenic organisms are called GMOs– Genetically Modified Organisms– Products they produce are biotechnology products

• Transgenic bacteria– Grown in bioreactors– Bacteria express cloned gene– Gene product collected from the media– Products include insulin, human growth hormone,

tPA, and hepatitis B vaccine

– Can be selected for their ability to degrade a particular substance

– Ability can be enhanced by bioengineering

– Eat oil, remove sulfur from coal

A. Transgenic bacteria

B. Transgenic plants

– Foreign genes introduced into:– Immature plant embryos– Protoplasts – plant cells with cell wall

removed» Go on to develop into mature plants

– Pomato:Not obtained from transfer of gene but from

the fusion of 2 cells (one from a tomato plant

and one from a potato plant.)

– Pest resistance in cotton, corn, and potato strains

Introduced a gene for insect

resistance from a bacteria into

a plant

– Soybeans resistant to herbicide– Can also be engineered to produce human

proteins

EXAMPLES GM PLANTS

C. Transgenic animals

– Insert genes into eggs–Example:

Insert gene for bovine growth hormone (bGH) to produce larger fishes, cows, pigs, rabbits, and sheep

–Gene pharming• Use of transgenic farm animals to produce

pharmaceuticals• Proteins harvested from animals milk


a.milk

human genefor growthhormone

human growthhormone

microinjection of human gene

donor of egg

development withina host goat

Transgenic goat produceshuman growth hormone.

3. Gene TherapyA. Testing DNA for genetic disorders

What is a Genetic markers?

• Disease caused by an abnormality in the sequence of their bases at a particular location on a chromosome

• Abnormality in sequence is called a genetic marker

A. Testing DNA for genetic disorders

DNA microarray or “gene chip

• Spot hundreds to thousands of known disease-associated mutant gene alleles onto chip

• Genomic DNA from person labeled with fluorescent dye added to chip

• Any spots that fluoresce correspond to mutant alleles in the person

• Genetic profiling

What is a microarray?

B. Preventing or curing disease through Gene Therapy

What is Gene Therapy?

– It involves the Insertion of genetic material into human cells to fight or prevent diseases.

– The mutant version of a gene is replaced or supplemented with a properly functioning one

– Viruses genetically modified to be safe can be used to ferry a normal gene into the body.

– 2 ways of administrating virus:

• Ex vivo (cells taken out of the body and injected with virus than put back into body)

• In vivo (directly injected into body)

defectivegene

1. Remove bone marrow stem cells.


EX VIVO GENE THERAPY


retrovirus

viralrecombinantRNA

normal gene

defectivegene

2. Use retroviruses to bring the normal gene into the bone marrow stem cells.




retrovirus

viralrecombinantRNA

normal geneviral recombinant RNA

normal gene

defectivegene

viral recombinant DNA

reverse transcription

2. Use retroviruses to bring the normal gene into the bone marrow stem cells.

3. Viral recombinant DNA carries normal gene into genome.

4. Return genetically engineered cells to patient.




Brain (gene transfer by injection)*• Huntington disease – Parkinson disease• Alzheimer disease – Brain tumors

Skin (gene transfer by modifiedblood cells)** - skin cancer

Lungs (gene transfer by aerosol spray)*• cystic fibrosis - hereditary emphysema

Liver (gene transfer by modified implants)**• familial hypercholesterolemia

Blood (gene transfer by bone marrow transplant)*• sickle-cell disease

Endothelium (blood vessel lining) (gene transfer by implantation of modified implants)**• hemophilia - diabetes mellitus

Muscle (gene transfer by injection)*• Duchenne muscular dystrophy

Bone marrow (gene transfer by implantation of modified stem cells)**•SCID (Severe Combined ImmunoDeficiciency)•sickle-cell disease * invivo

** ex vivo

Example: GENE THERAPY AND CANCERDifferent approaches to treat cancer through gene

therapy:

•Replace missing or altered gene that can cause cancer

•Improve patient’s immune response to cancer (enhance the natural ability of body to fight cancer cells)

•Insert genes into cancer cells to make them more susceptible to chemotherapy/radiotherapy… or make normal cells more resistants

4 Genomics and Bioinformatics

Genomics: Study of the complete genetic sequences of humans and other

organisms

Sequencing the human genome– Accomplished by 13-year effort of the Human

Genome Project (HGP)

– Humans have 20,00025,000 genes

– Most of the genes are expected to code for proteins– Found large area of Noncoding DNA , first called

“junk DNA”, may have important functions

– New genomes being sequenced all the time and at a much faster rate now

Comparative genomics

Compare genomes of organisms• Identify similarities between the sequence of

human bases and those of other organisms

Offers a way to study changes in the genome through time• Track evolution of HIV

Understand the evolutionary relationships among organisms• Human and chimpanzee 98% alike• Human and mouse 85% alike

OrganismHomo

sapiens (human)

Mus musculus (mouse)

Drosophila melanogaster

(fruit fly)

Arabidopsis thalania

(flowering plant)

C. Elegans (round worm)

S. Cerevisia (yeast)

Number of bases

3,000 millions

2,500 millions

180 millions125

millions97 millions 12 millions

Number of genes

20,500 30,000 13,600 25,500 19,100 6,300

Number of chromoso

mes46 40 8 10 12 32

Comparative genomics

Genome size does not correlate with evolutionary status, nor is the number of genes proportionate with genome size.

– Structural genomics knowing the sequence of the bases

and how many genes we have

– Functional genomics what does it code for (proteins)

– Understand the function of the various genes discovered within each genomic sequence and how these genes interact

– Help deduce the function of human genes by comparison to other genomes

– Use of a microarray can tell what genes are turned on in a specific cell or tissue type in a particular organism at a particular point in time and under certain environmental circumstances

Functional genomics

Technology

Chapter26