Chapter 13: Genetics and Chapter 13: Genetics and BiotechnologyBiotechnology

13.1 Applied Genetics13.1 Applied Genetics

13.2 DNA Technology13.2 DNA Technology

13.3 The Human Genome13.3 The Human Genome

13.1 Applied Genetics13.1 Applied Genetics Main idea: Selective breeding is used to produce Main idea: Selective breeding is used to produce

organisms with desired traitsorganisms with desired traits ObjectivesObjectives

Describe how selective breeding is used to produce organisms Describe how selective breeding is used to produce organisms with desired traitswith desired traits

Compare inbreeding and hybridizationCompare inbreeding and hybridization Assess the genotypes of organisms using a Punnett square test Assess the genotypes of organisms using a Punnett square test

crosscross Review VocabularyReview Vocabulary

Hybrid: organism that is heterozygous for a particular traitHybrid: organism that is heterozygous for a particular trait New VocabularyNew Vocabulary

Selective breedingSelective breeding InbreedingInbreeding Test crossTest cross

Selective BreedingSelective Breeding

The process by which desired traits of certain plants and animals are selected and passed on to their future generations is called selective breeding.

Selective BreedingSelective Breeding

Breeding for desired traits are not Breeding for desired traits are not restricted to animals alone.restricted to animals alone.

Plants are also breed to produce desired Plants are also breed to produce desired traits, such as larger fruits and shorter traits, such as larger fruits and shorter growing times.growing times.

Through the processes of hybridization Through the processes of hybridization and inbreeding, desired traits can be and inbreeding, desired traits can be passed on to future generations. passed on to future generations.

HybridizationHybridizationHybrid organisms can be bred to be more

disease-resistant, to produce more offspring, or to grow faster.

A disadvantage of hybridization is that it is time consuming and expensive.

Because hybrids can be bred to be more nutritious, to have the ability to adapt to a wide range of changes in the environment, and to produce greater numbers of offspring, the advantages of hybridization sometimes outweigh the disadvantages.

InbreedingInbreeding

The process in which two closely related organisms are bred to have the desired traits and to eliminate the undesired ones in future generations

Pure breeds are maintained by inbreeding. A disadvantage of inbreeding is that harmful

recessive traits also can be passed on to future generations.

Inbreeding increases the chance of homozygous recessive offspring.

Test CrossTest Cross

A test cross involves breeding an organism that has the unknown genotype with one that is homozygous recessive for the desired trait.

13.2 DNA Technology13.2 DNA Technology Main idea: Researchers use Main idea: Researchers use

genetic engineering to genetic engineering to manipulate DNA.manipulate DNA.

ObjectivesObjectives Describe how genetic Describe how genetic

engineering manipulates engineering manipulates recombinant DNA.recombinant DNA.

Compare selective breeding to Compare selective breeding to genetic engineeringgenetic engineering

Summarize how genetic Summarize how genetic engineering can be used to engineering can be used to improve human health.improve human health.

Review VocabularyReview Vocabulary DNA: the genetic material of DNA: the genetic material of

all organisms, composed of all organisms, composed of two complementary chains of two complementary chains of nucleotides wound in a double nucleotides wound in a double helix.helix.

New VocabularyNew Vocabulary Genetic engineeringGenetic engineering GenomeGenome Restriction enzymeRestriction enzyme Gel electrophoresisGel electrophoresis Recombinant DNARecombinant DNA PlasmidPlasmid DNA ligaseDNA ligase TransformationTransformation CloningCloning Polymerase chain reaction (PCR)Polymerase chain reaction (PCR) Transgenic organismTransgenic organism

Genetic EngineeringGenetic Engineering

Technology that involves manipulating the DNA of one organism in order to insert the DNA of another organism, called exogenous DNA.

For example, researchers have inserted a gene for bioluminescent protein called green fluorescent protein (GFP) into various organisms.

GFPGFP

Genetically engineered bollworm

Genetically Engineered Organisms are Used to:

study the expression of a particular gene. investigate cellular processes.study the development of a certain

disease.select traits that might be beneficial to

humans.

DNA ToolsDNA Tools

An organism’s genome is the total DNA in the nucleus of each cell.

DNA tools can be used to manipulate DNA and to isolate genes from the rest of the genome.

Restriction EnzymesRestriction Enzymes Restriction enzymes recognize and bind to

specific DNA sequences and cleave (cut) the DNA within the sequence.

Restriction enzymes were discovered in the 1970’s.

An endonuclease (restriction enzyme) cuts the viral DNA into fragments after it enters the bacteria.

Scientists use restriction enzymes as powerful tools for isolating specific genes or regions of the genome.

When the restriction enzyme cleaves genomic DNA, it creates fragments of different sizes that are unique to every individual.

EcoRIEcoRI

EcoRI specifically cuts DNA containing the sequence GAATTC.

The ends of the DNA fragments, called sticky ends, contain single-stranded DNA that is complementary.

Gel Electrophoresis

An electric current is used to separate DNA fragments according to the size of the fragments in a process called gel electrophoresis.

When an electric current is applied, the DNA fragments move toward the positive end of the gel.

The smaller fragments move farther faster than the larger ones.

Gel Electrophoresis

The unique pattern created based on the size of the DNA fragment can be compared to known DNA fragments for identification.

Gel electrophoresis

Recombinant DNARecombinant DNA The newly generated DNA molecule with DNA from

different sources is called recombinant DNA. Recombinant DNA enables scientists to study individual Recombinant DNA enables scientists to study individual

genes.genes. Large quantities of recombinant DNA molecules are Large quantities of recombinant DNA molecules are

needed to study individual genes.needed to study individual genes.

Recombinant DNA TechnologyRecombinant DNA Technology1.1. A carrier, called a vector transfers the recombinant DNA into a A carrier, called a vector transfers the recombinant DNA into a

bacterial cell called the host cell. Plasmids (small, circular bacterial cell called the host cell. Plasmids (small, circular double-stranded DNA molecules that occur naturally in double-stranded DNA molecules that occur naturally in bacteria) and viruses are commonly used vectors because bacteria) and viruses are commonly used vectors because they can be cut with restriction enzymes.they can be cut with restriction enzymes.

2.2. If a plasmid and a DNA fragment obtained from another If a plasmid and a DNA fragment obtained from another genome have been cleaved by the same restriction enzyme, genome have been cleaved by the same restriction enzyme, the ends of each DNA fragment will be complementary and the ends of each DNA fragment will be complementary and can be combined.can be combined.

3.3. An enzyme normally used by cells in DNA repair and An enzyme normally used by cells in DNA repair and replication, DNA ligase, joins the two DNA fragments replication, DNA ligase, joins the two DNA fragments chemically. Ligase joins DNA fragments that have sticky ends chemically. Ligase joins DNA fragments that have sticky ends as well as those that have blunt ends.as well as those that have blunt ends.

4.4. The resulting circular DNA molecule contains the plasmid The resulting circular DNA molecule contains the plasmid DNA and the DNA fragment isolated from another genome.DNA and the DNA fragment isolated from another genome.

5.5. This recombinant plasmid DNA molecule now can be inserted This recombinant plasmid DNA molecule now can be inserted into a host cell so that large quantities of this type of into a host cell so that large quantities of this type of recombinant DNA can be made.recombinant DNA can be made.

Gene CloningGene Cloning To make a large quantity of recombinant plasmid DNA,

bacterial cells are mixed with recombinant plasmid DNA. Some of the bacterial cells take up the recombinant

plasmid DNA through a process called transformation.

Gene Cloning (cont.)Gene Cloning (cont.) Large numbers of identical bacteria, each containing the inserted

DNA molecules, can be produced through a process called cloning. Clones containing copies of the recombinant DNA can be identified

and used for further study when the bacterial cells that do not contain the recombinant DNA die.

DNA SequencingDNA Sequencing To understand how DNA is sequenced, scientists mix an

unknown DNA fragment, DNA polymerase, and the four nucleotides—A, C, G, T in a tube.

DNA Sequencing (cont.)DNA Sequencing (cont.) Each nucleotide is

tagged with a different color of fluorescent dye.

Every time a modified fluorescent-tagged nucleotide is incorporated into the newly synthesized strand, the reaction stops.

The sequencing reaction is complete when the tagged DNA fragments are separated by gel electrophoresis.

Polymerase Chain ReactionPolymerase Chain Reaction

A technique called the polymerase chain A technique called the polymerase chain reaction (PCR) can be used to make reaction (PCR) can be used to make millions of copies of specific region of a millions of copies of specific region of a DNA fragment.DNA fragment.

Genetic EngineeringGenetic Engineering

BiotechnologyBiotechnology

Biotechnology – the use of genetic Biotechnology – the use of genetic engineering to find solutions to problems – engineering to find solutions to problems – makes it possible to produce organisms makes it possible to produce organisms that contain individual genes from another that contain individual genes from another organism.organism.

Organisms genetically engineered by Organisms genetically engineered by inserting a gene from another organism, inserting a gene from another organism, are called transgenic organismsare called transgenic organisms

Transgenic AnimalsTransgenic Animals Scientists produce most transgenic animals in Scientists produce most transgenic animals in

laboratories for biological research.laboratories for biological research. Mice, fruit flies, and the roundworm Mice, fruit flies, and the roundworm Caenorhabditis Caenorhabditis

elegans elegans to study diseases and ways to treat them.to study diseases and ways to treat them. Transgenic livestock – to improve food supply and Transgenic livestock – to improve food supply and

human health.human health. Transgenic goats – to secrete a protein called Transgenic goats – to secrete a protein called

antithrombin III, which is used to prevent human antithrombin III, which is used to prevent human blood from forming clots during surgery.blood from forming clots during surgery.

Transgenic chickens & goats to be resistant to Transgenic chickens & goats to be resistant to diseases.diseases.

Transgenic fish – to grow faster.Transgenic fish – to grow faster. Future transgenic organisms might be used as a Future transgenic organisms might be used as a

source of organs for organ transplants.source of organs for organ transplants.

Transgenic PlantsTransgenic Plants Plants have been genetically engineered to be Plants have been genetically engineered to be

more resistant to insect or viral pests, such as more resistant to insect or viral pests, such as herbicide- and insecticide-resistant soybeans, herbicide- and insecticide-resistant soybeans, corn, cotton, and canola.corn, cotton, and canola.

Researchers also are developing peanuts and Researchers also are developing peanuts and soybeans that do not cause allergic reactions.soybeans that do not cause allergic reactions.

Other crops are being field-tested: sweet-potato Other crops are being field-tested: sweet-potato plants that are resistant to a virus that could kill plants that are resistant to a virus that could kill most of the African harvest; rice plants with most of the African harvest; rice plants with increased iron and vitamins that could decrease increased iron and vitamins that could decrease malnutrition; and a variety of plants to survive malnutrition; and a variety of plants to survive extreme weather conditions, produce vaccines, extreme weather conditions, produce vaccines, and biodegradable plastics.and biodegradable plastics.

Transgenic BacteriaTransgenic Bacteria

Insulin, growth hormones, and substances Insulin, growth hormones, and substances that dissolve blood clots are made by that dissolve blood clots are made by transgenic bacteria.transgenic bacteria.

Transgenic bacteria also slow the Transgenic bacteria also slow the formation of ice crystals on crops to formation of ice crystals on crops to protect them from damage, clean up oil protect them from damage, clean up oil spills more efficiently, and decompose spills more efficiently, and decompose garbage.garbage.

13.3 The Human Genome13.3 The Human Genome Main idea: Genomes Main idea: Genomes

contain all of the contain all of the information needed for an information needed for an organism to grow and organism to grow and survive.survive.

Objectives:Objectives: Describe components of Describe components of

the human genome.the human genome. Describe how forensic Describe how forensic

scientists use DNA scientists use DNA fingerprinting.fingerprinting.

Explain how information Explain how information from the human genome from the human genome can be used to diagnose can be used to diagnose human diseases.human diseases.

Review VocabularyReview Vocabulary Codon: The triplet of bases Codon: The triplet of bases

in the DNA or mRNA.in the DNA or mRNA.

New VocabularyNew Vocabulary DNA fingerprintingDNA fingerprinting BioinformaticsBioinformatics DNA microarrayDNA microarray Single nucleotide Single nucleotide

polymorphismpolymorphism HaplotypeHaplotype PharmacogenomicsPharmacogenomics Gene TherapyGene Therapy GenomicsGenomics ProteomicsProteomics

The Human Genome ProjectThe Human Genome Project

The goal of the Human Genome Project (HGP) was to determine the sequence of the approximately three billion nucleotides that make up human DNA and to identify all of the approximately 20,000–25,000 human genes.

Sequencing the GenomeSequencing the Genome

Each of the 46 human chromosomes was cleaved.

These fragments were combined with vectors to create recombinant DNA, cloned to make many copies, and sequenced using automated sequencing machines.

Computers analyzed the overlapping regions to generate one continuous sequence

Decoding the Human GenomeDecoding the Human Genome

Decoding the sequence of the human genome can be compared to reading a book that was printed in code.

The Human GenomeThe Human Genome

Less than two percent of all of the nucleotides in the human genome code for all the proteins in the body.

The genome is filled with long stretches of repeated sequences that have no direct function.

These regions are called noncoding sequences.

DNA FingerprintingDNA Fingerprinting

Protein-coding regions of DNA are almost identical among individuals.

The long stretches of noncoding regions of DNA are unique to each individual.

DNA fingerprinting involves separating these DNA fragments to observe the distinct banding patterns that are unique to every individual.

Identifying GenesIdentifying Genes

Researchers have identified genes by scanning the sequence for Open Reading Frames (ORFs).

ORFs contain at least 100 codons that begin with a start codon and end with a stop codon.

Algorithyms use information, such as the Algorithyms use information, such as the sequence of the genomes of other sequence of the genomes of other organisms, to identify human genes.organisms, to identify human genes.

BioinformaticsBioinformatics

Creating and maintaining databases of biological information.

Finding genes in DNA sequences of various organisms and developing methods to predict the structure and function of newly discovered proteins.

DNA MicroarraysDNA Microarrays

Tiny microscope slides or silicon chips that are spotted with DNA fragments

Help researchers determine whether the expression of certain genes is caused by genetic factors or environmental factors.

The Genome and Genetic The Genome and Genetic DisordersDisorders

Variations in the DNA sequence that occur when a single nucleotide in the genome is altered are called single nucleotide polymorphisms or SNPs.

Regions of linked variations in the human genome are known as haplotypes.

The HapMap ProjectThe HapMap Project

Assembling the HapMap involves identifying groups of SNPs in a specific region of DNA.

The HapMap will enable geneticists to take advantage of how SNPs and other genetic variations are organized on chromosomes.

PharmacogenomicsPharmacogenomics

The study of how genetic inheritance affects the body’s response to drugs is called pharmacogenomics.

The benefits of pharmacogenomics include more accurate dosing of drugs that are safer and more specific to speed recovery and reduce side-effects.

Gene TherapyGene Therapy

A technique aimed at correcting mutated genes that cause human diseases is called gene therapy.

Scientists insert a normal gene into a chromosome to replace a dysfunctional gene.

Genomics and ProteomicsGenomics and ProteomicsGenomics is the study of an organism’s

genome. It is used to study genes and interpret their

functions.Genes are the primary information storage

units, whereas proteins are the machines of a cell.

The large-scale study and cataloging of the structure and function of proteins in the human body is called proteomics.

ProteomicsProteomics