BIOTECHNOLOGY Chapter 13

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

1. Inbreeding - Crossing similar genotypes w Closely related w Maintains desirable traits w Produces undesirable traits w 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 w Combines desirable traits of both parents w “hybrid vigor” - healthier offspring w Offspring usually sterile w 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 w Are changes in DNA w Ultimate source of variation! w Occur unexpected & randomly w Scientists speed up mutations by exposing organisms to chemicals or radiation

Radiated to produce small or no seeds Seedless Oranges Drawback – loose flavor

Genetic Engineering growing field of careers w Technique used to identify and/or alter genes at the molecular level w Faster method w Requires equipment, money

Genetic engineering 1. DNA fingerprinting by gel electrophoresis 2. PCR amplifies DNA 3. Transformation of DNA Transgenic organisms GMO foods Cloning

DNA fingerprinting w An identification system for individuals w A unique pattern of bands that represent segments of a person’s DNA w 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 w 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? ChildF1F2F3F4

Cell Transformation w DNA from one organism is taken into another ( sometimes unrelated ) organism w Tools required: 1.Restriction enzymes to cut DNA at specific sites 2.Vectors - “DNA taxis” to move the gene ( virus or plasmids)

Restriction Enzymes w Recognize DNA palindromes ex: RACECAR w Cut at specific sites

How Restriction Enzymes Work

Plasmid Vectors w Small circular pieces of bacterial DNA w 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 w Transgenic bacteria “Ice minus” gene, nitrogen fixing gene “oil eaters” HGH, insulin, interferon

w Transgenic plants resistant to herbicides produce own pesticide more protein prevent rotting more nutritious Broccoflower and Purple Cauliflower Aggie Beta-sweet Carrot

w 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 w Donated egg has nucleus removed w Fertilized using electricity with a diploid body cell w Implanted into surrogate mother to grow and develop

History of Cloning >>click on diagram to connect to internet

Gene Therapy w changing a gene that causes a genetic disorder w The bad gene is replaced with a working gene that makes the needed protein w Ex: Cystic Fibrosis inhalers

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