Genetics Lecture VGenetics Lecture V

Mutations and Genetic Modification

Mutations and Genetic Modification

Biology Standards Biology Standards CoveredCovered

Biology Standards Biology Standards CoveredCovered

Std 4c ~ students know how mutations in the DNA sequence of a gene may or may not affect the expression of the gene or the sequence of amino acids in an encoded protein

Std 5c ~ students know how genetic engineering (biotechnology) is used to produce novel biochemical and agricultural products

Std 4c ~ students know how mutations in the DNA sequence of a gene may or may not affect the expression of the gene or the sequence of amino acids in an encoded protein

Std 5c ~ students know how genetic engineering (biotechnology) is used to produce novel biochemical and agricultural products

MutationsMutations Mutations are changes

in the DNA sequence that affect genetic information

Genetic mutations result from changes in a single gene

Chromosomal mutations involve changes in whole chromosomes

Mutations are changes in the DNA sequence that affect genetic information

Genetic mutations result from changes in a single gene

Chromosomal mutations involve changes in whole chromosomes

MutationsMutationsMutations that only affect one

nucleotide are called point mutationsPoint mutations generally only affect one

amino acid in the sequenceTHE DOG BIT THE CATTHE DOG BIT THE CAR

Normal: AUG-AAG-GGC-UAA Protein: Met - Lys - Gly - StopNormal: AUG-AAG-AGC-UAA Protein: Met - Lys - Ser - Stop

Mutations that only affect one nucleotide are called point mutationsPoint mutations generally only affect one

amino acid in the sequenceTHE DOG BIT THE CATTHE DOG BIT THE CAR

Normal: AUG-AAG-GGC-UAA Protein: Met - Lys - Gly - StopNormal: AUG-AAG-AGC-UAA Protein: Met - Lys - Ser - Stop

MutationsMutationsFrameshift mutations are much more

dangerous to the genetic code!They occur when a nucleotide is added

(inserted) or deletedThis “shifts” the reading frame of the

geneTHE DOG BIT THE CAT

** What happens if you remove the “G” in DOG

THE DOB ITT HEC AT**The same would happen if you added a letter

Frameshift mutations are much more dangerous to the genetic code!

They occur when a nucleotide is added (inserted) or deleted

This “shifts” the reading frame of the geneTHE DOG BIT THE CAT

** What happens if you remove the “G” in DOG

THE DOB ITT HEC AT**The same would happen if you added a letter

SubstitutionInsertion

Deletion

Gene Mutations:Substitution, Insertion, and

Deletion

Gene Mutations:Substitution, Insertion, and

Deletion

Mutations can be very dangerous

and VERY SCARY!!

Mutations can be very dangerous

and VERY SCARY!!

MutationsMutationsChromosomal mutations involves the

change in the number or structure of chromosomes

There are Four Types:Deletion – the loss of all or part of a chromosomeDuplication – when a segment of a chromosome

is repeatedInversion – When part of a chromosome

becomes oriented in the reverse directionTranslocation – when part of a chromosome

breaks off and attaches to another

Chromosomal mutations involves the change in the number or structure of chromosomes

There are Four Types:Deletion – the loss of all or part of a chromosomeDuplication – when a segment of a chromosome

is repeatedInversion – When part of a chromosome

becomes oriented in the reverse directionTranslocation – when part of a chromosome

breaks off and attaches to another

Chromosomal Mutations

Chromosomal Mutations

Deletion

Duplication

Inversion

Translocation

Selective BreedingSelective Breedingselective breeding – – allowing allowing onlyonly

desired traits or characteristics to be desired traits or characteristics to be passed on from one generation of passed on from one generation of organism to the nextorganism to the next

This process requires time, patience, This process requires time, patience, and several generations of offspring and several generations of offspring before the desired effect is achievedbefore the desired effect is achieved

selective breeding – – allowing allowing onlyonly desired traits or characteristics to be desired traits or characteristics to be passed on from one generation of passed on from one generation of organism to the nextorganism to the next

This process requires time, patience, This process requires time, patience, and several generations of offspring and several generations of offspring before the desired effect is achievedbefore the desired effect is achieved

Selective BreedingSelective BreedingBy “selective breeding” we mean to:

Actively “select” desired traits or characteristics such as fruit shape, size, or color (like in tomatoes for example)

Through several generations, we breed for those desired traits until the “frequency of the allele” is increased

This is a means to increase the “likelihood” that these desired traits will appear

By “selective breeding” we mean to:Actively “select” desired traits or

characteristics such as fruit shape, size, or color (like in tomatoes for example)

Through several generations, we breed for those desired traits until the “frequency of the allele” is increased

This is a means to increase the “likelihood” that these desired traits will appear

Selective BreedingSelective BreedingNearly all domestic animals such

as horses, cats, dogs, and farm animals as well as many crops have been produced by selective breeding

The “famous” scientist Luther Burbank produced a disease resistant potato plant that saved Ireland from the “Potato Blight”

Nearly all domestic animals such as horses, cats, dogs, and farm animals as well as many crops have been produced by selective breeding

The “famous” scientist Luther Burbank produced a disease resistant potato plant that saved Ireland from the “Potato Blight”

Selective BreedingSelective BreedingOne of the

techniques that Luther used was hybridization – crossing dissimilar organisms to bring together the best of both organisms

One of the techniques that Luther used was hybridization – crossing dissimilar organisms to bring together the best of both organisms

Selective BreedingSelective BreedingHybrids :

Hybrids are often “hardier” than both of the parents

They are more resistant to diseases as well as temperatures and whatever they have been selectively bred to “resist”

Hybrids :Hybrids are often “hardier” than both of the parents

They are more resistant to diseases as well as temperatures and whatever they have been selectively bred to “resist”

Selective BreedingSelective BreedingHybrids continued

In many cases scientists have “hybridized” a plant with a high tolerance for diseases with a plant that produces large amounts of food

These are called genetically modified crops

Hybrids continued In many cases

scientists have “hybridized” a plant with a high tolerance for diseases with a plant that produces large amounts of food

These are called genetically modified crops

This is a special hybrid of extremely disease resistant and large spinach

This is a special hybrid of extremely disease resistant and large spinach

Selective BreedingSelective Breeding

Inbreeding – mating between closely related individuals

Inbreeding – mating between closely related individuals

Selective BreedingSelective Breeding

Inbreeding ensures that the offspring are homozygous for most traits

Inbreeding also can increase the likelihood of harmful recessive traits as well

Inbreeding ensures that the offspring are homozygous for most traits

Inbreeding also can increase the likelihood of harmful recessive traits as well

Increasing Variation

Increasing Variation

Nature already produces huge “variety” known as variation

We can see the HUGE diversity in the human species

“Breeders” can increase the variation in a population by “inducing” mutations (making them happen)

Nature already produces huge “variety” known as variation

We can see the HUGE diversity in the human species

“Breeders” can increase the variation in a population by “inducing” mutations (making them happen)

Increasing Variation

Increasing Variation

Breeders and scientists use “mutations” to increase variation in the population

Mutation – a heritable change in the DNA ONLY if it can be

“passed” to the offspring Mutations occur

regularly and are one of the factors in evolution. Sometimes, mutations are negative

Breeders and scientists use “mutations” to increase variation in the population

Mutation – a heritable change in the DNA ONLY if it can be

“passed” to the offspring Mutations occur

regularly and are one of the factors in evolution. Sometimes, mutations are negative

Genetic Modifications

Genetic Modifications

Polyploid – more than the normal amount of chromosomes in an organism

Plants are often engineered to be polyploid so that they are larger and sometimes stronger

Polyploid – more than the normal amount of chromosomes in an organism

Plants are often engineered to be polyploid so that they are larger and sometimes stronger

Manipulating and Recombining DNAManipulating and Recombining DNA

Each living organism has it’s own specific DNA that identifies that organism as an individualThink of DNA as a fingerprintEven each human, although we are all

“humans”, we all have slightly different DNAExcept identical twins which are

considered living clones

Each living organism has it’s own specific DNA that identifies that organism as an individualThink of DNA as a fingerprintEven each human, although we are all

“humans”, we all have slightly different DNAExcept identical twins which are

considered living clones

Manipulating and Recombining DNAManipulating and Recombining DNA

What if we could take segments of DNA and “create” any type of living organism we wanted?TODAY –

scientists have ways of doing just that !!

What if we could take segments of DNA and “create” any type of living organism we wanted?TODAY –

scientists have ways of doing just that !!

Manipulating and Recombining DNAManipulating and Recombining DNA

Scientists are using the information they have gathered so far about the structure of DNA to “cut & paste” their own sections

Scientists are able to “re-write” certain DNA codes and alter living organisms

Once you know the base-pairing rules you can cut out sections of DNA and insert sections wherever you wish

Scientists are using the information they have gathered so far about the structure of DNA to “cut & paste” their own sections

Scientists are able to “re-write” certain DNA codes and alter living organisms

Once you know the base-pairing rules you can cut out sections of DNA and insert sections wherever you wish

Genetic Engineering

Genetic Engineering

Genetic Engineering – making changes in the DNA code of a living organism

Restriction enzymes act like “keys” that fit into specific sequences of the DNA and “cut” them

Genetic Engineering – making changes in the DNA code of a living organism

Restriction enzymes act like “keys” that fit into specific sequences of the DNA and “cut” them

Restriction Enzymes cut DNA

DNA

Restriction enzyme cuts the DNA at specific site

Sticky end

Tools of Molecular Biology

Tools of Molecular Biology

DNA Extraction – process by which DNA is taken out of (extracted) from the cells of an organism

DNA Cutting – this is done by the restriction enzymes

Separating DNA – a process called gel electrophoresis is used to separate DNA into small fragments

DNA Extraction – process by which DNA is taken out of (extracted) from the cells of an organism

DNA Cutting – this is done by the restriction enzymes

Separating DNA – a process called gel electrophoresis is used to separate DNA into small fragments

Gel ElectrophoresisGel Electrophoresis After the DNA plus restriction enzymes are

added to the gel, an electric charge is passed through the gel

The genes separate out depending on size and the smaller genes move “faster” through the gel

After the DNA plus restriction enzymes are added to the gel, an electric charge is passed through the gel

The genes separate out depending on size and the smaller genes move “faster” through the gel

DNA plus restriction enzyme

Power source

Longer Longer fragmentsfragments

Shorter Shorter fragmentsfragments

GelMixture of DNA fragments

Cutting and Pasting DNA

Cutting and Pasting DNA

Recombinant DNA – when DNA is taken from one organism and incorporated into the DNA of another organism

Think of a gene that any plant or animal would have that you would like “spliced” into your DNA --- what gene would you want?

Recombinant DNA – when DNA is taken from one organism and incorporated into the DNA of another organism

Think of a gene that any plant or animal would have that you would like “spliced” into your DNA --- what gene would you want?

Making Copies of Genes

Making Copies of Genes

Copies of genes need to be made so that scientists can study them further

The process of “copying DNA” is known as the polymerase chain reactionHave any idea why it is called that?

Hint: “Polymerase”

Copies of genes need to be made so that scientists can study them further

The process of “copying DNA” is known as the polymerase chain reactionHave any idea why it is called that?

Hint: “Polymerase”

Cell Transformation

Cell Transformation

Cell transformation is when a cell takes in DNA from outside the cell and it becomes part of the “host” cell’s DNA In order for you to

“recombine” DNA into another organism you first have to get the gene from an organism

Your next step is to get it into the cell you intend on incorporating it into it’s DNA

Cell transformation is when a cell takes in DNA from outside the cell and it becomes part of the “host” cell’s DNA In order for you to

“recombine” DNA into another organism you first have to get the gene from an organism

Your next step is to get it into the cell you intend on incorporating it into it’s DNA

Recombinant DNA

Flanking sequences match HOST

Host Cell DNA

Target gene

Recombinant DNA replaces target gene

Modified Host Cell DNA

Cell Transformation

Cell Transformation

Transforming BacteriaPlasmid – a small,

circular DNA molecule

Found naturally in most bacteria

Plasmids are easy to work with and can be recombined outside of the cell, then placed back into the cell

Transforming BacteriaPlasmid – a small,

circular DNA molecule

Found naturally in most bacteria

Plasmids are easy to work with and can be recombined outside of the cell, then placed back into the cell

Plasmid

Bacterial chromosome

Animal cell with Nucleus

EcoRI ~ restriction enzyme removes the target gene

Bacterial plasmid opened

by restriction enzyme

Recombined plasmid

Human Cell

Gene for human growth

hormoneRecombinant DNA

Gene for human growth hormone

Sticky endsDNA

recombination

DNA insertionBacterial Cell

Plasmid

Bacterial chromosome

Bacterial cell for containing gene for

human growth hormone

Making Recombinant DNA in Bacterial CellsMaking Recombinant DNA in Bacterial Cells

Human Cell

Cell Transformation

Cell Transformation

Transforming Plant CellsPlasmids are also used to transfer

DNA into plant cellsSome plant cells take up DNA on

their own when their cell walls are removed

DNA can also be directly injected into some plant cells

The goal is to incorporate the DNA into at least one of the chromosomes

Transforming Plant CellsPlasmids are also used to transfer

DNA into plant cellsSome plant cells take up DNA on

their own when their cell walls are removed

DNA can also be directly injected into some plant cells

The goal is to incorporate the DNA into at least one of the chromosomes

Plant Cell Transformation

Plant Cell Transformation

Gene to be transferred

Recombinant plasmid

Cellular DNA

Transformed bacteria introduce plasmids into

plant cells

Inside plant cell, Agrobacterium inserts part of its DNA into host cell chromosome

Complete plant is Complete plant is generated from generated from transformed celltransformed cell

Vectors Transfer DNAVectors Transfer DNA

A plasmid is an example of a vector

A vector is any means by which DNA from another species can be carried into a host cell

A rejoining of DNA fragments is called gene splicing

A plasmid is an example of a vector

A vector is any means by which DNA from another species can be carried into a host cell

A rejoining of DNA fragments is called gene splicing

Gene Gene SplicingSplicing

Applying Genetic Engineering

Applying Genetic Engineering

Transgenic organisms – any organism that contains genes from another or many other organisms

Bacteria are primarily used to reproduce substances important to the health industry and to benefit humans

They are considered transgenic microorganisms and they are used to grow cultures of human genes because they reproduce rapidly and are easy to work with

Transgenic organisms – any organism that contains genes from another or many other organisms

Bacteria are primarily used to reproduce substances important to the health industry and to benefit humans

They are considered transgenic microorganisms and they are used to grow cultures of human genes because they reproduce rapidly and are easy to work with

Transgenic Animals

Transgenic Animals

Animals have been used to help scientists study the effect of hormones and drugs on the human body and also to culture large amounts of useful human proteins

They help us to : Study genes and improve our food supply Study the effect of diseases in humans Develop drugs to resist certain diseases Produce proteins essential to human

function

Animals have been used to help scientists study the effect of hormones and drugs on the human body and also to culture large amounts of useful human proteins

They help us to : Study genes and improve our food supply Study the effect of diseases in humans Develop drugs to resist certain diseases Produce proteins essential to human

function

Transgenic PlantsTransgenic Plants Many of the plants and produce that you see

daily in the grocery store are genetically modified

Many “crops” contain transgenic plants that can be resistant to disease and pests This enables growers to spray generously without

harming the plant Many of these chemicals stay on or in the plant as it

makes its way to your table Transgenic plants also have many of the

dominant traits that some of their “like” plants may contain in different parts of the world

Many of the plants and produce that you see daily in the grocery store are genetically modified

Many “crops” contain transgenic plants that can be resistant to disease and pests This enables growers to spray generously without

harming the plant Many of these chemicals stay on or in the plant as it

makes its way to your table Transgenic plants also have many of the

dominant traits that some of their “like” plants may contain in different parts of the world

CLONINGCLONINGA clone is an organism or sequence of

DNA that is genetically identical and produced from a single cell

If you were to clone yourself your clone would look exactly like you and have your exact and unique DNA sequenceAn identical twin is an example of a clone

Cloning makes many advancements possible in the realm of science but, the question is should it be done?

A clone is an organism or sequence of DNA that is genetically identical and produced from a single cell

If you were to clone yourself your clone would look exactly like you and have your exact and unique DNA sequenceAn identical twin is an example of a clone

Cloning makes many advancements possible in the realm of science but, the question is should it be done?

A donor cell is taken from a sheep’s udder

Donor Nucleus

These two cells are fused using an electric shock.

Fused Cell

The fused cell begins dividing normally.

Embryo

The embryo is placed in the uterus of a foster mother.

Foster Mother

The embryo develops normally into a lamb—Dolly

Cloned Lamb

Egg CellAn egg cell is taken from an adult female sheep.

The nucleus of the egg cell is removed.

Cloning of the First MammalCloning of the First Mammal