Download bio ch 15.3 ppt - Mrs. Graves Science

Gene Technologies and Human Applications
Section 3
Section 3: Gene Technologies in Detail
Preview
• 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
Visual Concept: Action of Restriction
Enzymes
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 results in 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 semisolid
• Often, DNA fragments are forced though a gel.
• Shorter fragments will move faster through the gel.
• The result is a lane of fragments sorted by size.
• There are many types of electrophoresis.
Gene Technologies and Human Applications
Section 3
Visual Concept: Gel Electrophoresis
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
includs:
– 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, blotting, DNA sequencing,
and gene recombination.
Gene Technologies and Human Applications
Section 3
Major Gene Technology Processes,
continued
Polymerase Chain Reaction (PCR)
• The polymerase chain reaction (PCR) process is
widely used to clone DNA sequences for further study or
manipulation.
• PCR imitates the normal process of DNA replication in
cells.
• The process is called a chain reaction because it is
repeated over and over.
Gene Technologies and Human Applications
Visual Concept: Polymerase Chain
Reaction
Section 3
Gene Technologies and Human Applications
Section 3
Major Gene Technology Processes,
continued
Blotting Processes and Applications
• Several gene technologies use a combination of
restriction enzymes, gel electrophoresis, and
hybridization with probes.
• The goal is to find or compare genetic sequences.
• These processes include:
–
–
–
–
Southern Blot
Fingerprints and Bar Codes
Northern Blot
Microarrays
Gene Technologies and Human Applications
Southern Blot
Section 3
Click to animate the image.
Gene Technologies and Human Applications
Visual Concept: Making a DNA
Fingerprint
Section 3
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
Chain Termination Sequencing
Click to animate the image.
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
Visual Concept: Using Plasmids to
Produce Insulin
Section 3
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
Managing Genomic Data
• The application of information technologies in biology is
bioinformatics.
• Genomic bioinformatics starts with the mapping and
assembly of the many parts of each genome.
• The major stages of this work include the following:
– Mapping and Assembly
– Organized Storage
– Annotation
– Analysis
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 help track genes, any detectable physical, behavioral, or
chemical trait can be used as a marker.
• 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
Gene Technologies and Human Applications
Section 3
Exploring Genomes, continued
Genome Sequence Assembly
• The process of deducing and recording the exact order of
every base and gene in a genome is called sequence
assembly.
• A collection of clones that represent all of the genes in a given
genome is called a genetic library.
• Two kinds of genetic libraries are made:
– genomic library
– expressed sequence tag (EST) library
• The data can be searched for any specific gene or sequence.
• Robotic devices are now used to sequence genomes rapidly.
Gene Technologies and Human Applications
Section 3
Summary
• 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.
• The major methods for working with genes use some combination of
the basic tools of cellular machinery. These methods include PCR,
blotting, DNA sequencing, and gene recombination.
• One can explore and map a genome at many levels, including
species, individual, chromosome, gene, or nucleotide. Genomic
bioinformatics starts with the mapping and assembly of the many
parts of each genome.