C13- Genetic Technology

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Transcript C13- Genetic Technology

C13- Genetic Technology
Pp. 336 - 365
Contents
• 13.1 Applied Genetics
• 13.2 Recombinant DNA Technology
• 13.3 The Human Genome
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Applied Genetics
• Selective Breeding- choosing organisms with the
most desired traits to serve as parents of the next
generation.
Applied Genetics
• Inbreeding- mating
closely related
individuals; results in
homozygous offspring
• Animal breed
• Plant cultivar
Applied Genetics
• Hybrids increase
productivity and disease
resistance in crops
• Usually larger and
stronger than purebred
parents
Hybrid sorghum
Determining Genotypes
• Test Crosses- unknown
genotype X known genotype
• Offspring ratios indicate
genotype of unknown parent
• Homozygous dominant if
100% heterozygote
• Heterozygous if 1:1 ratio
• P. 340
13.2 Recombinant DNA Technology
• Genetic Engineering
faster & more reliable
method to increase the
frequency of allele
• Involves cutting DNA
from one organism &
inserting it in another
• Recombinant DNA
Technology
Recombinant DNA Technology
• Transgenic organism
has foreign DNA
• Tobacco plant with
firefly DNA
Recombinant DNA Technology
• Three step process
Recombinant DNA Technology
• Step 1- isolate foreign DNA fragment to be inserted
• Step 2- attach DNA fragment to a carrier
• Step 3- transfer into host organism
Restriction Enzyme Cleaves DNA
•
• Restriction enzymes
bacterial proteins with
ability to cut DNA sequence
at specific nucleotide
sequence
• Palindromes-same sequence
in opposite orders
• Hundreds of restriction
enzymes
• Fragments have sticky ends
Vectors Transfer DNA
• Carrier that transports
foreign DNA into host
• Here a retrovirus serves as
vector for engineered bone
cells.
• Can be biological or
mechanical
• Bacterial plasmid is a small
ring of DNA
• Micropipette or DNA coated
bullet from a gene gun
• ML 13.1, p. 343
Gene Cloning
• Clones are genetically identical
copies
• Each identical recombinant DNA
molecule is called a gene clone.
• Recombinant DNA can be
inserted in yeast, plant cells and
animal cells.
Animal Cloning
• Dolly the sheep first
cloned animal, 1997
• Dewey, first cloned
deer, 2003
Polymerase Chain Reaction
• PCR method to replicate
DNA outside an organism
• Thermocycler uses heat to
separate DNA strands
• Enzyme used to repeatedly
replicate DNA
• Used in crime investigations
and diagnosis of infectious
disease
Sequencing DNA
• Sequencing DNA
allows scientists to
identify mutations
• Four tubes A, C, T & G
tagged with different
colors
• Strands separated by
size using gel
electrophoresis
Applications of DNA Technology
• Industrial
• Produce chemical
compounds
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Indigo for dye
Cheese production
Laundry detergent
Pulp & paper products
Sewage treatment
Applications of DNA Technology
• Medical
• Production of proteins
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Human growth hormone
Insulin
Antibodies
Enzymes
Applications of DNA Technology
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Agriculture
Crop development
Insect resistance
Genetically modified
crops
• Vitamin fortified food
• Allergy reduction
13.3 The Human Genome
• In 2003 scientists in the
Human Genome Project
obtained the DNA
sequence of 3 billion
base pairs making up
the human genome.
• It is nearly the same
(99.9%) in all people.
13.3 The Human Genome
• Only about 2% of the
human genome contains
genes which are the
instructions for making
proteins.
• Humans have about
30,000 genes; the
functions of more than
half of them are
unknown.
13.3 The Human Genome
• Almost half of human
proteins share
similarities with other
organisms, underscoring
the unity of life.
• Much is still unknown!
The Human Genome
• Genetic map that gives
the relative location of
genes on a chromosome
is called a linkage map.
• Crossover occurs during
prophase I of meiosis.
• Genes that crossover
frequently must be
farther apart.
The Human Genome
• Biotechnology increases
the efficiency of
mapping with new
methods such as
polymerase chain
reaction (PCR) to make
millions of copies of
DNA fragments
The Human Genome
• Sequencing the human
genome:
• 1) cleaving DNA into
fragments
• 2) cloning fragments
• 3) sequences aligned
• All automated
Applications
• Diagnosis of genetic
disorders
• Can be diagnosed
before birth using
amniotic fluid
• Isolating DNA
• Using PCR to analyze
Applications
• Gene Therapy
• Insertion of normal
genes into human cells
to correct genetic
disorders
• SCID, cystic fibrosis,
sickle cell anemia,
hemophilia
Applications
• New Methods of
Crime Detection
• DNA fingerprints from
non-coding DNA
segments unique to
individual
• Can be used even with
ancient DNA such as
mummies or historical
figures