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Genetics and Biotechnology
Chapter 13
Selective breeding is used to produce organisms with desired traits.
I. Applied Genetics
A. Selective Breeding
1. Defined-the process by which desired traits of certain plants and animals are
selected and passed on to their future generations.
a.
b. Ex. Breeding great tasting apple
2.
3. Hybridization
a. reminder-crossing organisms with different forms of a trait to produce
offspring with specific traits are hybrids.
-ex. Animal breeders, gardeners, scientist, etc.
b. select traits that will give the organism a competitive edge.
-ex. Plant with disease resistance crossed with fast growing plant
c.
-time consuming
d. ex. Rice breeders took 30 yrs to hybridize rice. It can adapt to
locations and more nutritious
4.
a. Finding a desired trait-inbreed to make sure it is becomes a ‘pure’
trait
b.
Ex. Clydesdale horses
c. Disadvantage to inbreeding
-increases the chances of homozygous recessive traits
to show up.
B.
1. Defined-breeding an organism with an unknown genotype with a homo. recessive.
a. If the unknown parent is homo dominant, all offspring will have the trait.
b. If the unknown parent is heterozygous, the offspring will have another
trait pop up. The phenotype ratio will be 1:1
2.
White grapefruits are dominant while red is recessive.
W-white, w-red
White = WW or Ww
Red = ww only
Breeder wants only white grapefruits.
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Before he chooses a plant to cross, he/she wants to know if it a pure white grapefruit with WW and
not a Ww.
Breeder performs a test cross with a
red (ww) grapefruit.
WW x ww
Ww x ww
II.
Researchers use genetic engineering to manipulate DNA
A.
1. Defined-Manipulating the DNA of one organism in order to insert the
DNA of another organism.
a. ex. Extract DNA that causes light from lightning bug to a plant.
b.
c. Transgenic organisms
2.
a. agriculture
b.
c. studying the development of a certain disease
d. selecting traits that might be beneficial to humans.
3. What risks are associated with genetically engineered products?
a.
b. loss of native organisms
B.
1. Intro
a. Genome-the total DNA presen in the nucleus of each cell.
-humans have MILLIONS of nucleotides in their genome
-scientist must be able to isolate only the part of the
DNA they are studying.
b.
-Restriction enzymes
-Gel electrophoresis
2.
a. Defined-proteins which recognize and bind to specific DNA sequences and
cleave (cut) the DNA within that sequence
b.
-because they constantly fight against viruses entering their DNA
-
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c. scientists have isolated hundreds of these restrictive enzymes for use in
DNA research.
d.
-cut specific genes from DNA
3. EcoRI
a. restrictive enzyme
b. Unique in that it has ‘sticky ends’
-sticky ends lets them bind to other DNA and hook together.
c. Other restrictive enzymes which are not sticky (blunt) then the
fragments with 2 blunt ends can hook together.
4.
a. Defined-the ability to separate DNA fragments by using an electric
current.
b.
-DNA separates according to density and charge. Positive and
negative ends in the gel.
c.
C. Recombinant DNA Technology
1.
a. recombinant DNA (rDNA)
-two DNA’s from different sources are combined.
A large amount of rDNA is needed for research. One must make the rDNA quickly and accurately.
b. Scientists use bacteria as factories to make any kind of DNA segment
needed to study.
c.How do we make bacteria __________factories for us?
Bacteria have a circular DNA and bits of DNA fragments called plasmids.
Biotechnology companies sell plasmids that allow researchers to create rDNA with special
properties. For example, genes that glow, tags, etc.
How do you get the part of the DNA into the bacterial DNA? (viruses or plasmids can be used as
vectors to infect the bacteria with the ‘wanted’ gene to be studied)
DNA ligase enzyme pinches together the ‘wanted’ gene into the circular DNA of the bacteria.
The bacterial DNA now has been infected (by way of the vector) with the new gene and has
Bacterial DNA that has been changed a bit with the new piece of DNA.
Now ____________________________________________________
The bacteria now has new instructions to pump (make/synthesize) NEW product….such as insulin…
etc.
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2.
a. defined-making an exact copy of a gene.
b. using bacteria as factories to keep cloning the gene.
3.
a. Most DNA sequencing unknown in most organisms.
b. Knowing the DNA sequence gives valuable information concerning the
function of the organism.
-comparing of genes with similar sequences
-to identify mutations errors in the DNA sequence.
4.
a. Function
-Makes copies of specific regions of sequenced DNA
b.
-Used to copy DNA for any scientific investigation, including forensic
analysis and medical testing.
c. PCR can detect a single DNA molecule in a sample. Very powerful tool.
D.
1. Defined-the use of genetic engineering to find solutions to problems.
2.
a. when an organism has its own DNA and a bit from another organism.
b. ex. Glowing Tobacco Plants
-DNA from firefly
3. Transgenic animals
-Cows which produce more milk.
-Goats make a protein in their milk to prevent clotting during
surgery
-Chickens/Turkey that is resistant to diseases
-Future~making organs for organ transplants?
4.
a. Genetically engineered to be more resistant to insect or viral pests.
(7million farmers in 18 countries)
-soybean
-cotton
b. Developing peanuts and soybeans that do not cause allergic reactions.
c. Rice with more iron and vitamins for third world countries.
d. Variety of plants resistant to extreme weather conditions.
e. working on banana’s that may produce vaccines and plants that produce
biodegradable plastics!
5.
a. Used to produce
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-growth hormones
-blood clot blaster
b. Used to slow the formation of ice crystals on crops to protect them from
frost
c.
d. Decompose garbage
III.
Genome contain ALL of the information needed for an organism to grow and survive. (readable
cookbook of DNA)
A.
1.
2.
International project finished in 2003
G
a. Defined-complete genetic information in a cell.
b. Human genome = 3 billion nucleotides!
c. Human genome-if fused together as font size from text, it would extend
from California to South America
d. studied the genomes of smaller organisms to help handle larger organisms
(mice, fruit fly, bacteria)
3.
a. use just 2% of the nucleotides to make proteins for the body!
Same in all humans (ex. Heart location etc.)
b. 98% are noncoding sequences!
-UNIQUE to each person
4.
a. Noncoding sequences different in every individual
b.
c. People can be identified using the genetic information contained in blood,
hair, semen, or skin.
B.
1. Defined-field of study which involves creating and maintaining databases of
biological information
2.
C. DNA Microarrays
1. Microscope slides or silicon chips with known DNA fragments
2. Researchers can dye areas of study on a DNA and study them simultaneously
P. 377
D.
1. Sections of DNA sequences may be altered by a single nucleotide in the genome.
These are called ‘single nucleotide polymorphisms’.
2.
a. regions of linked variations
b. identifying groups of SNP’s in a specific location on a DNA
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3.
a. The study of how genetic inheritance affects the body’s response to
drugs.
b. Helps to accurately dose drugs for an individual.
-c
-will allow for increase of safety, speed of recovery and reducing
side effects.
4.
a. Defined- a technique aimed at correcting mutated genes that cause human
diseases
b. Scientists insert a normal gene into a chromosome to replace a
dysfunctional gene.
-rDNA put in a virus—virus infects the area—DNA is corrected.
-trials for immune deficiency illnesses, diabetes, cancer, retinal
disease, Parkinson’s, and more.