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Gene Technologies and Human Applications
Section 3
Section 3: Gene Technologies in Detail
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• Bellringer
• Key Ideas
• Basic Tools for Genetic Manipulation
• Major Gene Technology Processes
• Exploring Genomes
• Summary
Gene Technologies and Human Applications
Section 3
Bellringer
Genetic Engineering in Agriculture
Write the name of a fruit or vegetable that you don’t like to
eat and explain why you don’t like it.
Then write about ways in which the fruit or vegetable could
possibly be changed by genetic engineering so that you
would like it.
Gene Technologies and Human Applications
Section 3
Key Ideas
• What are the basic tools of genetic manipulation?
• How are these tools used in the major processes of
modern gene technologies?
• How do scientists study entire genomes?
Gene Technologies and Human Applications
Section 3
Basic Tools for Genetic Manipulation
• The basic tools of DNA manipulation rely on the
chemical nature of genetic material and are adapted
from natural processes discovered in cells.
• These tools include restriction enzymes, polymorphisms,
gel electrophoresis, denaturation, and hybridization.
Gene Technologies and Human Applications
Section 3
Basic Tools for Genetic Manipulation,
continued
Restriction Enzymes
• A restriction enzyme cuts
double-stranded DNA into
fragments by recognizing
specific nucleotide
sequences and cutting the
DNA at those sequences.
• These enzymes can be
used to cut up a DNA
sample in specific ways
and to create sticky ends
for splicing DNA.
Gene Technologies and Human Applications
Section 3
Basic Tools for Genetic Manipulation,
continued
Polymorphisms
• Differences between the DNA sequences of individuals
are called DNA polymorphisms.
• Differences of just one nucleotide are called single
nucleotide polymorphisms (SNPs).
• Differences in restriction sites is called restriction
fragment length polymorphisms (RFLPs).
Gene Technologies and Human Applications
Section 3
Basic Tools for Genetic Manipulation,
continued
Gel Electrophoresis
• Electrophoresis is a process in which electrically
charged particles move through a liquid or a gel
• Often, DNA fragments are forced though a gel.
• Shorter fragments will move faster.
• The result is a lane of fragments sorted by size.
Gene Technologies and Human Applications
Section 3
Basic Tools for Genetic Manipulation,
continued
Denaturation
• Some conditions, can cause DNA to denature, or untwist and
split into single strands.
• Scientists can easily denature and renature DNA for further
manipulations.
Hybridization
• Under the right conditions, complementary segments of DNA
or RNA will bind together, or hybridize.
• Genetic tools that take advantage of this natural process
includes:
– Primers
– Probes
– cDNA
Gene Technologies and Human Applications
Section 3
Major Gene Technology Processes
• The major methods for working with genes use
some combination of the basic tools and
mechanisms of cellular machinery.
• These methods include PCR, DNA
sequencing, and gene recombination.
Gene Technologies and Human Applications
Section 3
Major Gene Technology Processes,
continued
Polymerase Chain Reaction (PCR)
• The PCR process is widely used to clone
DNA sequences for further study or
manipulation.
• PCR imitates the normal process of DNA
replication.
• The process is called a chain reaction
because it is repeated over and over.
Gene Technologies and Human Applications
Section 3
Major Gene Technology Processes,
continued
DNA Sequencing
• DNA sequencing is the process of determining the
exact order of every nucleotide in a gene.
• The major modern method is chain termination
sequencing.
• The steps are:
1. Start Copying a Template
2. Randomly Terminate the Copies
3. Sort the Copies by Size
Gene Technologies and Human Applications
Section 3
Major Gene Technology Processes,
continued
Gene Recombination and Cloning
• The first attempts at gene recombination and cloning
were done by inserting a gene into an organism that
replicates easily.
• The steps were:
1. Cut DNA Samples
2. Splice Pieces Together
3. Place into Host
4. Replicate Gene
5. Screen for Gene
• Other methods may use similar steps.
Gene Technologies and Human Applications
Section 3
Exploring Genomes
• One can view a map of an entire nation or “zoom in” to
view a particular state, city, neighborhood, or street.
• In a similar way, one can explore and map a genome at
many levels, including species, individual, chromosome,
gene, or nucleotide.
Gene Technologies and Human Applications
Section 3
Exploring Genomes, continued
Mapping Methods
• Genome mapping is the process of determining the relative
position of all of the genes on chromosomes in an organism’s
genome.
• To determine the relative locations, genome mapping may use
several methods:
– Linkage Mapping methods identify the relative order of genes
along a chromosome.
– Physical Mapping methods determine the exact number of base
pairs between specific genes.
– Human chromosome mapping has mostly used historical family
records.
Gene Technologies and Human Applications
Basic Genome Mapping
Section 3