Starter Question!

Can you determine what two dog crosses make up the

following breeds?

A. Chi-Poo

B. Cockeranian

C. Bassugg

D. Daniff

A

D

C

B

A. Chihuahua and Poodle B. Cocker Spaniel and the Pomeranian.C. Basset Hound and Pug D. Great Dane and Mastiff

A brief history of dogs…• All dog breeds can be traced back

to a common ancestor, the gray wolf.

Does this remind you of your pet?

A brief history of dogs…

There several theories that attempt to explain how domestic dogs descended from gray wolves.

1. Stone age humans would watch groups of wolves and breed the tame ones with each other. This lead to a population of tame wolves.

2. Tame wolves were more comfortable scavenging through Stone Age dumping grounds. Since they were not afraid of humans, they were able to obtain more food and had a better chance of survival, thus reproducing more tame wolves.

3. While not widely done in society today, in some places dogs are still used as a food/fur source. Domestic dogs may have resulted through this relationship.

A brief history of dogs…

So where did Fluffy and Fido come from?

The tame wolves soon became domesticated dogs. These dogs started to breed and produce variations. After countless generations, these variations lead to current day breeds of dogs.

Increasing Variation

• Mutations are the ultimate source of genetic variation.

• These occur spontaneously; some can be harmful and some can be beneficial.

Example

There are 3 sizes of poodles. Standard, Miniature, and Toy.

Standards (to the left) are the oldest known of the three.Standard Poodle

Example

A mutation can occur that results in differences in size, shape, etc…Breeders can take advantage of these mutations to create more desirable pets.

Standard Poodle Standard Poodle Miniature Poodle

Example

Miniature Poodle Miniature Poodle Toy Poodle

Selective Breeding

• The previous example takes advantage of naturally occurring variation to pass desired traits to the next generation of organisms.

• Essentially, selective breeding increases the frequency of desired alleles in a population.

Hybridization• Crossing dissimilar individuals to

bring together the best of both organisms.

• These organisms are known as hybrids.

Labradoodle (cross between a Labrador Retriever and a

Standard or Miniature Poodle)

Puggle (cross between a Beagleand a Pug)

BiotechnologyToday, scientists have a much faster and more effective way to manipulate variation and selection… manipulation of DNA!

Biotechnology includes:- Transgenic Organisms- Clones -Genetic Engineering- Gene Therapy - PCR- Gel Electrophoresis

The Human Genome

• A genome is the entire DNA in an organism. • After a genome is completed scientists have a “map”

showing where particular genes are located on a chromosome

• The particular order of As, Ts, Cs, and Gs in a genome is extremely important. The order will tell whether an organism is human or another species such as yeast, rice, or fruit fly, all of which have their own genomes.

• The human genome, has 3 billion pairs of bases. If you started reading the sequence out loud right now, it would take almost 10 years to read the entire thing!!!

The Human Genome Project• Organized in 1990 by US scientists; international effort to map and

sequence the genes on the 46 human chromosomes• Completed in 2003, with final papers published in 2006• Project goals were to :

* identify all the approximately 20,000-25,000 genes in human

DNA,

* determine the sequences of the 3 billion chemical base pairs that

make up human DNA,

* store this information in databases,

* improve tools for data analysis,

* transfer related technologies to the private sector, and

* address the ethical, legal, and social issues (ELSI) that may arise

from the project.

The Human Genome Project

• How is this important to us? – Diagnosis of genetic disorders– Gene therapies

– http://www.youtube.com/watch?v=FZh_CPT84nI– http://www.youtube.com/watch?v=6ldtdWjDwes&

NR=1

Genetic Engineering• Genetic engineering is manipulating genes

for practical purposes

• May involve building recombinant DNA-Recombinant DNA is DNA made from two or more different organisms

• This is how we are able to put jellyfish “glowing” genes in the bacteria

• Can result in a transgenic organism with recombinant DNA

Transgenic OrganismsTransgenic: any organism that has a

segment of DNA that was not originally their own.

Scientists can take DNA from an organism, cut out a particular gene they want, make millions of copies of it, and insert those copies into the cells of a different organism of choice.

The organism will then show the characteristics of that new gene.

Transgenic OrganismsWhat do you get when you take a sequence of firefly DNA and add it to the DNA of a tobacco plant?

A glowing tobacco plant!

Transgenic OrganismsGenetic material from jellyfish were injected into the womb of a sow which gave birth to the three pigs 114 days later.

Transgenic Organisms

The mouth, trotters and tongue of the pigs are green under ultraviolet light.

Applications

• Transgenic bacteria:– Important for health, industry, and the environment (used

in medicines, help clean up oil spills, etc.)

• Transgenic plants:– food supply (increased nutrition, resistance to certain plant

diseases)

• Transgenic animals:– Used to study genes and improve the food supply (altered

to grow faster, stronger, and produce higher yields)

Cloning

• Cloning is the process of making a genetically identical organism

• (Dolly was the first cloned organism from an adult cell)

Cloning• Many genetically identical cells can be

produced from a single cell• Cloning IS NOT “Xeroxing” a person• Cloning re-creates the genes of the

ancestor, not what he has learned or experienced.

• Technically, it re-creates the genotype, not the phenotype

Cloning

Gene Therapy• Gene Therapy is the process of

replacing an absent or faulty (bad) gene with a normal,

working gene.• Still relatively

experimental

Polymerase Chain Reaction (PCR)

Sometimes scientists need to get many copies of a specific DNA sequence (gene) very quickly so they perform a Polymerase Chain Reaction.

PCR works like this: 1. Scientists place a fragment of DNA in a machine,

2. They heat-shock it to cause the hydrogen bonds to come lose

3. They add nucleotides into the mix and an enzyme that will bond the complimentary bases to the loose sides of the DNA fragment,

4. Then cold-shock it to cause the hydrogen bonds to reform.

Basically, PCR is a really fast way of making a cell undergo DNA replication millions of times outside of the cell in just a few hours.

Invaluable when only a tiny sample of DNA is available (like trace evidence in a crime scene or the last bit of pulp from a fossil tooth)

You could make millions of identical DNA sequences in approximately 2 hours!

http://www.youtube.com/watch?v=HMC7c2T8fVk&NR=1

Applications? • Scientists

discovered a preserved Wooly Mammoth and if they wanted to clone it they would need to perform a PCR to generate larger quantities of the preserved DNA

Gel Electrophoresis• Gel Electrophoresis is a technique used to

separate DNA fragments by fragment length• The bands that are created are unique to

each person (since DNA sequences are unique to each person)

Gel ElectrophoresisThe Process1. The same sections of DNA from multiple

people are cut into smaller pieces using restriction enzymes.

Restriction enzymes are the “molecular scissors” that cut DNA into specific pieces.

2. The pieces are then negatively “charged”, meaning that when they come in contact with an electric current, they move towards the positive end (like a magnet).

Gel Electrophoresis3. They are then loaded into a gel 4. Electric current is then run through

the gel.

The negative DNA fragments move through the gel towards the positive end.

Since the DNA sections are all different sizes, the bands separate by size.

Larger pieces move slower.

Bands of DNA fragments

Larger Pieces

Smaller Pieces

Applications of Gel Electrophoresis

DNA testing for paternity cases:• Every person’s DNA fragments separate

out a little bit differently in an Electrophoresis Gel, because we are all different. So, individuals can be identified by the banding pattern their DNA makes in the gel.

• Children have a combination of both their parents’ DNA, so when trying to determine parents, the children will have a combination of their parent’s bands.

Can you determine the correct suspect?

At a crime scene involving a murder, police recovered skin cells under the victim’s fingernails. The DNA in the skin cells was analyzed- it was not the victim’s, and thus was presumed to be the assailant’s. Three suspects were arrested for matching the description given by several witnesses. Their individual DNA was analyzed, and the results are shown below. Can the correct suspect be determined?

Crime scene Suspect #2Suspect #1 Suspect #3