Download Chapter 13- Genetic Engineering

Chapter 13- Genetic Engineering
13-1
*What do Goldendoodles, Labradoodles, and Puggles have in
common?
*All are a result of Selective Breeding- allowing only animals with
desired characteristics to produce the next generation.
Nearly all domestic animals (cats, horses, etc) and lots of crop plants
have been produced by selective breeding
*Important Historical Example: Luther Burbank (American)
-developed disease-resistant Burbank potato
-exported to Ireland to help fight potato blight and
other diseases
Hybridization- crossing similar organisms to bring together
the best of both organisms
Hybrids produced are often hardier than parents
Inbreeding-continued breeding of individuals with similar
characteristics
good- maintaining certain characteristics
bad- genetic defects- greater risk of recessive alleles
joining and causing problems (ex: blindness, hip
problems)
Reminder: What is a mutation?
-changes in genetic material
-Mutations:
-ultimate source of genetic variation.
-inheritable changes in DNA
-Breeders can increase genetic variation in a population by
increasing mutations.
-Mutations occur spontaneously
-can increase rate by using radiation and chemicals
1
New Bacteria
-small: millions can be treated with radiation or chemicals
at same time
-increases chance of producing useful mutant
-ex: produced bacteria that digest oil – used to clean
up oil spills
New Kinds of Plants
-Polyploidy-organism w/extra set of chromosomes
-usually fatal in animals
-Plants= larger and stronger
-ex: crops- bananas and many citrus fruits
13-4 Genetic Engineering
Genetic Engineering makes it possible to transfer DNA
sequences (including whole genes) from 1 organism to
another
From animals to plants????
1986- scientists isolated gene for luciferase
-enzyme- makes fireflies glow
-inserted into tobacco cells
-plant glowed in dark
-showed basic mechanisms of gene expression are
shared by plants and animals
Transgenic Organisms- contain genes from other species
Biotechnology- manipulation of organisms to do practical
things and to provide useful products
Transgenic Microorganisms
-Proteins: insulin, growth hormone, clotting factor
-used to treat serious human diseases and
conditions
2
-used to be expensive and rare
-Bacteria transformed with human protein now
produce these compounds
-now cheaper and easier
Transgenic Animals
-used to study genes and improve food supply
-mice- immune systems made to act like human
immune systems
-allows scientists to study effects of diseases
-livestock (cattle, pigs)- some now have extra copies
of growth hormone genes
-grow faster; produce leaner meat (less fat)
-Researchers trying to produce chickens resistant to
bacteria that causes food poisoning.
Transgenic Plants (also called Genetically Modified-GM)
-Year 2000- 52% of soybeans and 25% corn grown in U.S.
were transgenic or genetically modified (GM)
-contain natural insecticide
-resist chemicals –kill weeds w/out hurting crop
-Rice with Vitamin A- important for human health
-some countries rely on rice as main food
= sure to get vitamin = improve health?
Cloning
-clone- member of a population of genetically identical
cells produced from a single cell
-bacterial clones- easy to grow; -multicellular clones
(animals)- more difficult
-1997- Dolly the sheep; scientist Ian Wilmut
-figure 13-13
-cloning may help save endangered species
-problems: genetic defects and health problems
3