Genetic EngineeringGenetic Engineering

Think of the possibilitiesThink of the possibilities

Video

Selective BreedingSelective BreedingSelective Breeding

Selective breeding allows only those organisms with desired characteristics to produce the next generation.

Nearly all domestic animals and most crop plants have been produced by selective breeding.

Example: Champion race horses, cows with tender meat, large oranges on a tree.

Selective BreedingSelective Breeding Artificial selection- where individuals

with desirable traits are mated to produce offspring with those traits.

Hybridization 

Hybridization is the crossing of dissimilar individuals to bring together the best of both organisms.

Hybrids, the individuals produced by such crosses, are often hardier than either of the parents.

InbreedingInbreeding  

Inbreeding is the continued breeding of individuals with similar characteristics.

Inbreeding helps to ensure that the characteristics that make each breed unique will be preserved.

Serious genetic problems can result from excessive inbreeding.

WHY?

Inbreeding and VariationInbreeding and Variation

Recessive genetic disorders can be blindness, or joint deformities.Variation is a term used to identify the difference between individuals of a species.For example: Some humans have blond hair and some have brown. This is a variation among humans.

Finches-

Increasing VariationIncreasing Variation

Why might breeders try to induce mutations?Why might breeders try to induce mutations?

Breeders increase the Breeders increase the genetic variationgenetic variation in a in a population by inducing population by inducing mutationsmutations..

Producing New Kinds of BacteriaProducing New Kinds of BacteriaIntroducing mutations has allowed scientists to Introducing mutations has allowed scientists to developdevelop hundreds of hundreds of usefuluseful bacterial strains, bacterial strains, including including bacteriabacteria that can clean up oil spills. that can clean up oil spills.

Genetics EngineeringGenetics Engineering

In genetic engineering, biologists make changes in the DNA code of a living organism.

How do scientists make changes to DNA?

Scientists use different techniques to:

extract DNA from cells

cut DNA into smaller pieces

identify the sequence of bases in a DNA molecule

make unlimited copies of DNA

The Tools of Molecular BiologyThe Tools of Molecular BiologyEach Each restriction enzymerestriction enzyme cuts DNA at a specific cuts DNA at a specific sequence of nucleotides. sequence of nucleotides.

How do scientists manipulate DNA How do scientists manipulate DNA

1. DNA is removed from 1. DNA is removed from the cell of an the cell of an organism organism

2. DNA is cut using 2. DNA is cut using restriction enzymes to restriction enzymes to identify the bases.identify the bases.

3. There are thousands of 3. There are thousands of restriction enzymes, restriction enzymes, each cuts the DNA at each cuts the DNA at a different starting a different starting place based in the place based in the nucleotide sequence. nucleotide sequence.

4. DNA fragments are 4. DNA fragments are separated by gel separated by gel electrophoresis. electrophoresis.

5. Positive charged DNA moves 5. Positive charged DNA moves to negative poles and to negative poles and negative DNA moves to negative DNA moves to positive poles. Smaller positive poles. Smaller fragments move faster, larger fragments move faster, larger move slower. move slower.

6. This is also how DNA is 6. This is also how DNA is compared (ex at crime compared (ex at crime scenes)scenes)

7. Then, unlimited copies of 7. Then, unlimited copies of fragments are made by fragments are made by scientist. scientist.

Nova: who done itNova: who done ithttp://www.pbs.org/wgbh/nova/sheppard/analyze.html

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http://www.dnalc.org/resources/animations/http://www.dnalc.org/resources/animations/restriction.htmlrestriction.html

Cell TransformationCell Transformation

13-3 Cell Transformation13-3 Cell Transformation

Recombinant DNA

Host Cell DNA

Target gene

Modified Host Cell DNA

Cell TransformationCell Transformation

During transformation, a cell takes in DNA from outside the cell. The external DNA becomes a component of the cell's DNA.

Foreign DNA is first joined to a small, circular DNA molecule known as a plasmid.

Plasmids are found naturally in some bacteria and have been very useful for DNA transfer.

The plasmid has a genetic marker —a gene that makes it possible to distinguish bacteria that carry the plasmid (and the foreign DNA) from those that don't.

Biotechnology and genetic engineeringBiotechnology and genetic engineering

Genetic engineering is making changes in the DNA code of a living organism. A scientist can take genes from one organism and transfer them to another organism. This is called transformation.Genetic engineering has given rise to a new technological field called biotechnology (technology of life).The organisms that have DNA transferred to them are called transgenic.(trans: means different, genic: refers to genes)

Transgenic helpful?Transgenic helpful?

How are transgenic organisms useful to human How are transgenic organisms useful to human beings?beings?

Transgenic bacteria produce important Transgenic bacteria produce important substances useful for health and industry. substances useful for health and industry. Transgenic bacteria have been used to produce:Transgenic bacteria have been used to produce:

insulininsulin growth hormonegrowth hormone clotting factorclotting factor

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Recombinant DNA

Gene for human growth hormone

Gene for human growth hormone

Human Cell

Bacteria cell

Bacterial chromosome

Plasmid

Sticky ends

DNA recombination

Bacteria cell containing gene for human growth hormone

DNA insertion

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http://www.youtube.com/watch?v=8rXizmLjegI

Animals and plantsAnimals and plants

Transgenic animals: genes inserted into Transgenic animals: genes inserted into animals so they produce what humans need. animals so they produce what humans need.

A way to improve the food supply: livestock A way to improve the food supply: livestock given genes that make them grow faster or resist given genes that make them grow faster or resist bacteria that cause infections.bacteria that cause infections.

Mice are given human genes that make their Mice are given human genes that make their immune system work like ours. They can now immune system work like ours. They can now be used for researching the human immune be used for researching the human immune systemsystem

Transgenic PlantsTransgenic Plants

Transgenic plants: plants are given genes Transgenic plants: plants are given genes that make them produce a natural that make them produce a natural pesticide. Now they donpesticide. Now they don’’t have to be t have to be sprayed with cancer causing pesticides. sprayed with cancer causing pesticides.

25% of all corn is like this. It called 25% of all corn is like this. It called genetically modified or GM. genetically modified or GM.

Cloning Cloning

CloningCloning

A A cloneclone is a member of is a member of a population of a population of genetically genetically identicalidentical cells produced from a cells produced from a single cellsingle cell..

In 1997, Ian Wilmut In 1997, Ian Wilmut cloned a sheep called cloned a sheep called DollyDolly..

Dolly and Bonnie

CloningCloning

Donor Nucleus

Fused cell

Embryo

Egg Cell

Foster MotherCloned Lamb

CloningCloning

1.1. A single cell is removed from a parent A single cell is removed from a parent organism. organism.

2.2. An entire individual is grown from that An entire individual is grown from that cell. cell.

3.3. Remember one cell has all the DNA it Remember one cell has all the DNA it needs to make an entire organism. needs to make an entire organism.

4.4. Each cell in the body has the same DNA, Each cell in the body has the same DNA, but cells vary because different genes but cells vary because different genes are turned on in each cell. are turned on in each cell.

DollyDollyDolly was the first animal cloned.Dolly was the first animal cloned.She had the same exact DNA as She had the same exact DNA as her mother and had no father.her mother and had no father.Cloning is a form of asexual Cloning is a form of asexual reproduction.reproduction.Since Dolly, cats and other Since Dolly, cats and other organisms have been cloned. organisms have been cloned. The cat that was cloned had the The cat that was cloned had the same exact DNA but different same exact DNA but different color fur than the mother. color fur than the mother. How can this be?How can this be?Environment plays a huge part Environment plays a huge part in the way organisms develop.in the way organisms develop.

http://content.tutorvista.com/biology_11/content/media/cloning.swf

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Cool cloning vidsCool cloning vids

http://videos.howstuffworks.com/discovery/38036-discovery-news-tech-http://videos.howstuffworks.com/discovery/38036-discovery-news-tech-human-cloning-video.htmhuman-cloning-video.htm

http://videos.howstuffworks.com/tlc/29324-understanding-cloning-a-cow-http://videos.howstuffworks.com/tlc/29324-understanding-cloning-a-cow-video.htmvideo.htm

http://videos.howstuffworks.com/tlc/29134-understanding-saving-endangered-species-with-cloning-video.htm

http://videos.howstuffworks.com/science-channel/39069-popscis-future-of-organ-factory-video.htm

Human Genome Human Genome

Human ChromosomesHuman Chromosomes

Human ChromosomesHuman ChromosomesCell biologists analyze chromosomes by looking at Cell biologists analyze chromosomes by looking at

karyotypeskaryotypes..

CellsCells are are photographedphotographed during during mitosismitosis. Scientists . Scientists then cut out the then cut out the chromosomeschromosomes from the from the photographs and group them together in pairs.photographs and group them together in pairs.

A A picture of chromosomes picture of chromosomes arranged in this way is arranged in this way is known as a known as a karyotypekaryotype..

Human KaryotypeHuman Karyotype

Human TraitsHuman Traits

Pedigree Charts Pedigree Charts A A pedigreepedigree chart shows the chart shows the relationshipsrelationships within a within a famliyfamliy. .

Genetic counselors analyze pedigree charts to Genetic counselors analyze pedigree charts to infer the genotypes of family members.infer the genotypes of family members.

Human TraitsHuman TraitsA circle representsa female.

A horizontal line connecting a male and a female represents a marriage.

A shaded circle or square indicates that a person expresses the trait.

A square representsa male.

A vertical line and a bracket connect the parents to their children.

A circle or square that is not shaded indicates that a person does not express the trait.

Human GenesHuman Genes

Blood Group GenesBlood Group GenesHuman blood comes in a Human blood comes in a varietyvariety of genetically of genetically

determined blood groups.determined blood groups.

A A numbernumber of of genesgenes are responsible for human are responsible for human bloodblood groups. groups.

Human GenesHuman Genes

Recessive AllelesRecessive AllelesMany disorders are caused by autosomal Many disorders are caused by autosomal recessiverecessive

alleles.alleles.

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Human GenesHuman Genes

From Gene to MoleculeFrom Gene to MoleculeSickle Cell DiseaseSickle Cell DiseaseSickle cell Sickle cell disease is a disease is a

common genetic disorder common genetic disorder found in African Americans. found in African Americans.

It is characterized by the bent It is characterized by the bent and twisted shape of the and twisted shape of the red blood red blood cells.cells.

Sex-Linked GenesSex-Linked Genes

Sex-Linked GenesSex-Linked GenesThe The XX chromosome and the chromosome and the YY chromosomes chromosomes determine sex.determine sex.

Genes located on these chromosomes are called Genes located on these chromosomes are called sex-linked genessex-linked genes..

More than 100 sex-linked genetic disorders have More than 100 sex-linked genetic disorders have now been mapped to the now been mapped to the XX chromosome. chromosome.

Sex-Linked GenesSex-Linked Genes

The The YY chromosome is chromosome is much smaller than the X much smaller than the X chromosome and appears chromosome and appears to contain only a few to contain only a few genes.genes.

Sex-Linked GenesSex-Linked Genes

For a recessive allele to be expressed in For a recessive allele to be expressed in females, there must be two copies of the females, there must be two copies of the allele, one on each of the two X allele, one on each of the two X chromosomes.chromosomes.

Males have just one X Males have just one X chromosome. Thus, all X-linked chromosome. Thus, all X-linked alleles are expressed in males, alleles are expressed in males, even if they are recessive.even if they are recessive.

Chromosomal DisordersChromosomal Disorders

The most common The most common errorerror in in meiosismeiosis occurs when occurs when homologous chromosomes homologous chromosomes failfail to to separateseparate..

This is known as This is known as nondisjunctionnondisjunction, which means, , which means, ““not coming apart.not coming apart.””

If nondisjunction occurs, If nondisjunction occurs, abnormalabnormal numbers of numbers of chromosomes may find their way into gametes, and chromosomes may find their way into gametes, and a disorder of chromosome numbers may result.a disorder of chromosome numbers may result.

Chromosomal DisordersChromosomal DisordersDown syndrome Down syndrome produces mild to produces mild to severe mental severe mental retardation.retardation.It is characterized It is characterized by:by:

increased increased susceptibility to susceptibility to many diseases many diseases higher frequency of higher frequency of some birth defectssome birth defects

Down Syndrome Karyotype

The Human Genome ProjectThe Human Genome Project

A A genomegenome is is allall the the DNADNA in one cell of an in one cell of an organism.organism.

The main goal of the Human Genome The main goal of the Human Genome Project was to Project was to identify the DNA sequence identify the DNA sequence of every gene in the human genome. It of every gene in the human genome. It was completed in May 2006.was completed in May 2006.

Scientists estimate that human DNA has Scientists estimate that human DNA has around 25,000 genes.around 25,000 genes.

Gene TherapyGene Therapy

In In gene therapygene therapy, an absent or faulty gene is , an absent or faulty gene is replacedreplaced by a normal, by a normal, workingworking gene. gene.

The body can then make the correct protein or The body can then make the correct protein or enzyme, eliminating the cause of the disorder.enzyme, eliminating the cause of the disorder.

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Gene TherapyGene TherapyVirusesViruses are often are often used because of used because of their ability to enter a their ability to enter a cellcell’’s s DNADNA..

Virus particles are Virus particles are modified so that they modified so that they cannot cause cannot cause disease.disease.

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Gene TherapyGene Therapy

A A DNADNA fragment containing a fragment containing a replacementreplacement genegene is spliced to viral DNA. is spliced to viral DNA.