Mutations & Genetic Engineering

Indicator B – 4.8: Compare the consequences of mutations in body

cells with those in gametes.

Indicator B – 4.9: Exemplify ways that introduce new genetic

characteristics into an organism or a population by applying the principles of modern genetics.

Mutation:mutagen, mutant cell, gene mutation,

chromosomal mutation, nondisjunction Beneficial mutations Pedigree Genetic Engineering:

gene map, genome, cloning, gene therapy, stem cells

Selective Breeding: Inbreeding, hybridization

Students have no previous knowledge of this concept. It has not been addressed in previous grades.

A mutation is an alteration of an organism’s DNA and can range in severity.

Most mutations are automatically repaired by the organism’s enzymes, but those that are not repaired may result in altered chromosomes or genes.

Mutant body cells are not passed on to offspring but mutant gametes may be inherited.

In some cases, mutations are beneficial to organisms. A pedigree is a chart constructed to show an

inheritance pattern within a family through multiple generations.

Genetic engineering is the process of replacing specific genes in an organism in order to ensure that the organism expresses a desired trait.

Cloning, gene therapy, and hybridization are applications of genetic engineering.

Compare the consequences of mutations in body cells with those in gametes. Recall the causes of mutations. Classify mutations as resulting from sex cell or somatic cell alterations. Classify mutations as genetic or chromosomal. Exemplify genetic or chromosomal disorders. Interpret a pedigree with regard to the nature of specific traits

within a family. Exemplify ways that introduce new genetic characteristics into

an organism or a population. Recognize types of genetic engineering and selective breeding. Summarize the purposes of the various types of genetic

engineering and selective breeding. Compare selective breeding and hybridization. Summarize the benefits & drawbacks of the types of genetic

engineering & selective breeding.

1. Mutation 2. Point mutation3. Frameshift mutation 4. Mutagen5. Clone6. Genetic engineering7. Recombinant DNA8. Transgenic9. Genomics10. Human Genome Project11. Gene therapy12. Artificial selection (selective breeding)

A mutation is any change in the DNA sequence that causes a change in the amino acid sequence, thus a variation in the protein.

Mutations can occur many ways:They can be inherited from the parent(s).They can occur in an egg or sperm cell just

after fertilization.They can be acquired during the organism’s

lifetime.

Fertilized Egg

Mutation Occurs

Body Cells of Offspring

Mutation

SpermEgg

Mutations in Gametes

Can be passed on to offspring.

May result in poorly formed or nonfunctional

proteins. May be lethal.

Mutations in Somatic Cells Not passed on to

offspring. Can interfere with cell

function. Due to mitosis, the

mutation will be passed on to other cells.

Two types:Gene MutationsChromosomal Mutations

Result from changes in a single gene.

Point mutation Occur at a single

point. A nucleotide can be

substituted for another and can change the entire sequence of amino acids therefore messing with the protein.

Normal Reading Frame:

THE FLY HAD ONE RED EYE

Point Mutation on Reading Frame: THE FLY HID ONE RED EYE

Remember: DNARNAAmino Acidsproteins.

Due to a point mutation in the Beta Globin gene.

DNA should be C T C but is actually C A C. RNA should be G A G but is actually G U G. This change causes a change in the amino

acid.

Normal hemoglobin & RBC Sickled hemoglobin & RBC

Frame-shift Mutation Involves deletions

and insertions of nucleotides.

Can change the entire reading frame of the codon, thus causing problems with the protein.

Normal Reading Frame: THE FLY HAD ONE RED EYE

Insertion: THE FLY QHA DON ERE DEY

Deletion: THE FLH ADO NER EDE YE

Remember DNARNAAmino Acidsproteins.

video segment

Involves changes in the number or structure of chromosomes.

May change the locations of genes on the chromosomes and even the number of copies of some.

Four types: Deletion Duplication Inversion Translocation

May lead to genetic

disorders

There are many different chromosomal mutation disorders. The following slides highlight just a few of these. They do contain images that may be hard for some students to view, so please view them with caution.

http://medgen.genetics.utah.edu/photographs/pages/trisomy_13.htm

http://www.plasticsurgery4u.com/klinefelters_xxy/index.html

Down Syndrome is the most recognizable of these, but there are others.

Turner Syndrome

http://www.genome.gov/19519119

Cri du Chat Syndrome

http://www.genome.gov/19517558

Polyploidy usually leads to death in animals.

Some plants are successful with extra set(s) of chromosomes.

http://waynesword.palomar.edu/hybrids1.htm#watermelon

In some cases mutations are beneficial to organisms. Beneficial mutations are changes that may be useful to organisms in different changing environments. These mutations result in phenotypes that are favored by natural selection and increase in population.

Antibiotic resistant bacteria is an example of a beneficial mutation-at least from the point of view from the bacteria.

Mutations can lead to genetic disorders.

By examining a pedigree, geneticists can also see the likelihood of an individual inheriting a genetic disorder.

A pedigree is a chart constructed to show an inheritance pattern within a family through multiple generations. Through the use of a pedigree chart and key, the genotype and phenotype of the family members and the genetic characteristic can be tracked.

Unaffected Female

Unaffected Male

Mating

OffspringAffected female offspring

Unaffected male Offspring

Changes are possible that will NOT lead to a change in the protein…not a mutation.

Mutations occur about 1/100 000 000 bases.

Wobble position: 3rd base in codon provides protection against mutation.

Ex: CCA, CCG, CCC, CCU = proline DNA has proofreading enzymes that can

repair mismatches before transcription.

The role of DNA polymerase is to proofread a frame before it is ready to be translated. Often, this enzyme can catch a mutation before it goes through translation, but not always. If the mutation is caught and correct, the organism will never be affected. However, if it doesn’t then the organism will be affected.

Mutagens are factors such as radiation, chemicals, ultraviolet light, etc. that can cause changes in DNA. Some are natural, others are not.

Check out some mutagens....and what they do!

Mutagens

Since ALL living things use DNA as their genetic material, it is possible to insert DNA from one species to another, either through a cross if the organisms are of the same species, or through recombinant DNA if the organisms are dissimilar.

Scientists are now able to manipulate, or handle and change, DNA within organisms.

They are able to examine DNA on an entirely new level because of increases in technology.

They are able to change DNA or extract DNA from one organism and place it in another. However, this is not always successful.

Genetic engineering the process of replacing specific genes in an organism in order to ensure that the organism expresses a desired trait. Accomplished by taking

specific genes from one organism and placing them into another organism.

Genetic engineering occurs when scientists know exactly where genes occur on chromosomes. A gene map shows this.

Genome refers to all the genetic material in an organism.

The Human Genome Project that mapped the DNA sequence of human genes is useful in identifying genes for specific traits.

In cloning, an identical copy of a gene or an entire organism is produced. Cloning brings benefits but may also result in genetic disorders or health problems.

In gene therapy, scientists insert normal genes into absent or abnormal genes. Once inserted, the normal gene begins to produce the correct protein or enzyme, eliminating the cause of the disorder. However, gene therapy has had limited success because the hose often rejects the injected genetic material.

Plants that make natural insecticides, are higher in protein, or spoil more slowly.

Animals that are bigger, are faster growing, or are resistant to disease.

Bacteria that produce hormones such as human insulin or human growth hormones.

In humans, it is theoretically possible to insert copies of normal genes into the cells of people with different genetic disorders.

Why would you want to selectively breed an organism?

How is selective breeding done?

What are some organisms that are often products of selective breeding?

Selective breeding is the method of artificially selecting and breeding only organisms with a desired trait to produce the next generation. Almost all domesticated animals and most crops have been selectively bred.

Pug Beagle

Puggle

***What would have to be done to make the puggle a breed?

***What evidence would we have that a new breed had been created?

Canis familiarisCanis familiaris

Canis familiaris

In order to keep lines of breeds pure, breeders will often interbreed their organism, called inbreeding. While the line will stay pure, it may also result in many genetic disorders and problems. The drawback being recessive gene defects often show up.

Tiger + Lion = Liger

http://members.diaryland.com/edit/adclick.phtml?a=709142448 http://www.eriksaunders.com/archive.FEB05.htm

Top 10 Animal HybridsPanthera tigris x Panthera leo

K: AnimaliaP: ChordataC: MammaliaO: PrimatesF: HomindaeG: PanS: troglodytes

K: AnimaliaP: ChordataC: MammaliaO: PrimatesF: Homindae G: ?S: ?

http://www.primarilyprimates.org/videos/index.html

They say that the closest relative of humans is the chimpanzee. Would a hybrid be possible?

K: AnimaliaP: ChordataC: MammaliaO: PrimatesF: HominidaeG: HomoS: sapiens

Faster than selective breeding. Only 1 generation needed. More predictable results than selective

breeding. Can transfer traits from species that are

completely unrelated.

These fluorescent Zebrafish contain DNA of a sea anemone to cause their glow.

Corn earworms frequently destroy corn crops. GM Corn can be made to produce a protein that kills these insects—corn that makes its own pesticide.

GM chickens in Israel can be grown featherless, but more meaty—a benefit to farmers.

GOOD: can increase world food supply—can make farming easier

BAD: can aggravate food allergies—too much use of antibiotics— risk of pesticide resistance

“ORGANIC” food products that have not had any genetic modification.

Are organic foods healthier? Should they cost more?Is there any danger posed by eating GM foods?Should food labels indicate the GM of the food products?

Guess What’s for Dinner!!