BIOTECHNOLOGYChapter 13

Selective Breeding Done for thousands of years “Farmer Brown” Produce desirable traits “mother nature” to alter genes Requires time

1. Inbreeding - Crossing similar genotypes

Closely related Maintains desirable traits Produces undesirable traits Done with horses, dogs, cattle,

plants

Golden Retriever Puppies

If inbreed incorrectly may have problems with hip dysplasia, ears, eyes….

2. Hybridization- Crossing different genotypes Combines desirable traits of

both parents “hybrid vigor” - healthier offspring Offspring usually sterile Horses + donkeys = mule

Sweet & Hardy Corn

Most crop plants have been hybridized for certain traits.

Traits like : more vitamins, certain colors/flavors, larger, won’t freeze…

3. Mutations

Are changes in DNA

Ultimate source of variation!

Occur unexpected & randomly

Scientists speed up mutations by exposing organisms to chemicals or radiation

Radiated to produce small or no seeds Seedless Oranges

Drawback – loose flavor

Genetic Engineeringgrowing field of careers

Technique used to identify and/or alter genes at the molecular level

Faster method Requires equipment, money

Genetic engineering

1. DNA fingerprinting by gel electrophoresis

2. PCR amplifies DNA3. Transformation of DNA

• Transgenic organisms• GMO foods• Cloning

DNA fingerprinting

An identification system for individuals

A unique pattern of bands that represent segments of a person’s DNA

The process is known as gel electrophoresis

•DNA is cut into segments with restriction enzymes

•DNA is poured into agarose gel and electric current is added

•DNA segments travel across gel and appear as bands when dye is added

How does it work ? ? ?

How they are used Scientists look for matching bands

1. Comparisons with crime scene sample can ID individuals as guilty or innocent

2. Paternity testing

Suspect #1

Suspect #2

Crime scene evidence

Who is the father?......

Child F1 F2 F3 F4

Cell Transformation

DNA from one organism is taken into another (sometimes unrelated) organism

Tools required:1.Restriction enzymes to cut

DNA at specific sites2.Vectors - “DNA taxis” to

move the gene ( virus or plasmids)

Restriction Enzymes

Recognize DNA palindromes ex: RACECAR

Cut at specific sites

How Restriction Enzymes Work

Plasmid Vectors Small circular pieces of bacterial DNA Sections of DNA can be:

• removed• manipulated •reinserted by “gluing” back into DNA using the base pairing rule!

Plasmid Vectors

Producing a Trangenic Organism

Applications of DNA Technology

Transgenic bacteria

•“Ice minus” gene, nitrogen fixing gene

•“oil eaters”•HGH, insulin, interferon

Transgenic plants

• resistant to herbicides• produce own pesticide• more protein• prevent rotting• more nutritious

Broccoflower and Purple

Cauliflower

Aggie Beta-sweet Carrot

Transgenic animals

• cows with more milk• goats, pigs, cows with human

proteins•cow milk with missing enzymes•cloning

+ =

“silk milk” = light weight with steel strength

Cloning

Donated egg has nucleus removed Fertilized using electricity with a

diploid body cell Implanted into surrogate mother to

grow and develop

History of Cloning

>>click on diagram to connect to internet

Gene Therapy

changing a gene that causes a genetic disorder

The bad gene is replaced with a working gene that makes the needed protein

Ex: Cystic Fibrosis inhalers

Homework

Read the article on page 330 Write answers to #1 & #2