Major Concepts for 4th 6 weeks

• Mendel Genetics – Slides 2-25• Pedigrees – Slides 26-36• DNA and RNA (protein synthesis) – Slides 37-

73• Genetic Disorders – Slides 74-78• Mutations – Slides 79-101• Genetic Engineering – Slides 102 -117

Mendel Genetics

• Objectives:• Predict the outcome of a cross between parents

of know genotype.• Determine the probability of a particular trait in

an offspring based upon the genotype of parents and the particular mode of inheritance.

• Incomplete dominance, co-dominance, multiple alleles, polygenic, complete dominance, and sex-linked

Word Wall

Homozygous

Heterozygous

Genotype

Phenotype

GeneAllele

Gamete

Hybrid

True-breeding

Sex Cells – Egg and Sperm

TT or tt

Physical TraitTall

Tt

Form of gene (T or t)2 Alleles (one from each parent that code for trait)

The actual genetic make-upTT:Tt:tt

Big Eyes are dominant = BB or BbSmall eyes = bb

Punnett square example

Alleles for Female

Alleles for male

Both parents are heterozygousYy x Yy

PossibleGenotypes of Offspring1 YY:2 Yy: 1 yyPhenotype –3:1

Genotype = Phenotype = Probability =

R R

r

r4 Rr (heterozygous)4 round100% round

RR or Rr= roundrr = wrinkled

Rr Rr

Rr Rr

Cross a homozygous Round with wrinkled

Parents are RR which is same (homozygous) alleles for dominant and rr which are same for recessive trait

In a Punnett square, theAlleles always move to squares as shown.

The actual alleles

Physical description of trait

Genotype = Phenotype = Probability =

R r

R

r1 RR:2Rr:1rr3 Round, 1 wrinkled75% round, 25% wrinkled

RR or Rr= roundrr = wrinkled

RR Rr

Rr rr

Cross a hybrid with a hybrid

Parents are Rr which is heterozygousCLASSIC – Mendel Hybrid CrossDominant – 75%Recessive – 25%

In a Punnett square, theAlleles always move to squares as shown.

The actual alleles

Physical description of trait

*Determine recessive trait by small number showing the trait

Independent Assortment

• Alleles separate independently during the formation of gametes.

The dihybrid crossEeTt x EeTt

Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.

Cross: TtYy x TtYy

TY

TY

Ty

Ty

tY

tY

ty

ty

Tall, yellow Tall, yellow

9 tallplants with

yellow seeds

3 tallplants withgreen seeds

3 dwarfplants with

yellow seeds

1 dwarfplant with

green seeds

Tall, yellow Tall, yellow

Tall, yellow Tall, green Tall, yellow Tall, green

Tall, yellow Tall, yellow Dwarf, yellow Dwarf, yellow

Tall, yellow Tall, green Dwarf, yellow Dwarf, green

TTYY TTYy TtYY TtYy

TTYy TTyy TtYy Ttyy

TtYY TtYy ttYY ttYy

TtYy Ttyy ttYy ttyy

Genotypes:

Phenotypes:

1 TTYY : 2 TTYy : 4 TyYy : 2 TtYY : 1 TTyy : 2 Ttyy : 1 ttYY : 2 : 1 ttyyttYy

Mendel’s Peas Dihybrid Cross

Notice Phenotype Ratio9:3:3:1

Incomplete DominanceJapanese four-o-clock flowers

• Red flower plant genotype = RR• White flower plant genotype = WW• Pink flower plant genotype = RWAppear blended. Incomplete, not Full

Strength.

Genotype = Phenotype = Probability =

R R

W

W4 RW4 Pink100% Pink

RR = RedWW = whiteRW = Pink

RW RW

RW RW

Cross a Red flower with a White Flower

Parents are RR for red and WW for white. Both are homozygous or true breeding.

In a Punnett square, theAlleles always move to squares as shown.

The actual alleles

Physical description of trait

Co Dominance

Roan Cow

FULL Strength

RR x WW = RW orRR X R’R’ = RR’

NOTE: Alleles can be represented different ways. RR for Red, WW for White,RW for Roan or RR for Red, R’R’ for white, and RR’ for Roan. Let’s look at a Punnett Square with both examples.

Genotype = Phenotype = Probability =

R W

W

W2 RW, 2 WW2 Roan, 2 White50% Roan, 50% White

RR = Red cowWW = white cowRW = Roan Cow

RW WW

RW WW

Cross a Roan cow with white cow. Co-Dominance

Parents are RW for Roan which is heterozygous WW which is homozygous for White

In a Punnett square, theAlleles always move to squares as shown.

The actual alleles

Physical description of trait

Genotype = Phenotype = Probability =

R R’

R’

R’2 RR’, 2 R’R’2 Roan, 2 White50% Roan, 50% White

RR = Red cowR’R’ = white cowRR’ = Roan Cow

RR’ R’R’

RR’ R’R’

Cross a Roan cow with white cow. Co-Dominance

Parents are RW for Roan which is heterozygous WW which is homozygous for White

In a Punnett square, theAlleles always move to squares as shown.

The actual alleles

Physical description of trait

Multiple Alleles

• When more than two alleles (form of gene) contribute to the phenotype.

• Human blood types are an example• There are three possible alleles: A,B, and O• Both A and B are dominant over O.• O is recessive • AB is an example of Co-Dominance

6 different genotypes, 3 different Alleles

• IAIA

• IAi• IAIB

• IBIB

• Ibi• i i Type O

Type AB

Type A - 2 possible genotypes

Type B – 2 possible genotypes

Genotype = Phenotype = Probability =

IA i

IB

IB

IAIB, IBi2 AB, 2 B50% AB, 50% B

A = IAIA, IAiB= IBIB, IBiAB =IAIB O = ii

IAIB IBi

IAIB IBi

Cross a heterozygous type A with homozygous type B

Punnett square theAlleles always move to squares as shown.

The actual alleles

Physical description of trait

Polygenic traits• Traits controlled by two or more

genes.• Lots of variation in trait.• Examples:

–Human height,eye and skin color

Figure 11.17

Skin Color

Autosomal and Sex-Linked Traits

• Autosomal - Traits controlled by genes on chromosomes 1 -22.

• Sex-Linked – Traits controlled by the X chromosome or the Y chromosome.

• Most often sex-linked traits are on the X chromosome.

• Let’s look at some of examples and work together.

Genotype = Phenotype =

Probability =

Xn Y

XN

XnXNXn,XnXn,XNY,XnY2 Females, 1 Normal, 1 Color-blind2 Males, 1 Normal, 1 Color-blind50% Colorblind

Female = XXMale = XYNormal = N, color-blind = n

XNXn XNY

XnXn XnY

Cross a heterozygous female with a colorblind male

The actual alleles

Physical description of trait

Work like any other Punnett Square. Remember no letter on the Y.The trait is connected to the X!

Test Your Knowledge of Punnett Square

• http://www.biology.clc.uc.edu/courses/bio105/geneprob.htm

Sex Cells (Gametes) from Meiosis1N

EGG

Pedigrees

• Apply pedigree data to interpret various modes of genetic inheritance.

A pedigree is a chart of the genetic history of family over several generations.

Scientists or a genetic counselor would find out about your family history and make this chart to analyze.

Symbols in a Pedigree Chart

• Normal Female• Affected female Female carrier Not all

pedigrees show carriers

Normal Male Affected Male

Male carrier – Not possible in Sex-linked traits (if you see carrier male, it is autosomal)

Female is represented by a circle

Male is represented as a square

What does a pedigree chart look like?

1st generation

2nd generation

3rd generation

• Does this pedigree show a sex-linked trait?• Yes, males are affected more than females, and females are carriers.• How many children were born in generation 2 to couple with affected male?• 3, 2 boys and a girl.• What is the genotype of the female in generation 3?• XNXN

• What are genotypes for generation 1?

XNYXNXn

XNXNXnY

1st generation

2nd generation

3rd generation

XNYXNXN or XNXn

XnY

This is the same pedigree without female carriers being shown. The large affect it has on males, tells us it is sex-linked and since it is not showing up in females, it is recessive. NOT all pedigrees will show carriers, so be careful with analyzing!

If carriers are not shown, genotype could be homozygous or heterozygous even though trait is not shown.

XNXN or XNXn

Interpreting a Pedigree Chart

1. Determine if the pedigree chart shows an autosomal or X-linked disease.

– If most of the males in the pedigree are affected the disorder is most likely X-linked

– If it is a 50/50 ratio between men and women the disorder is most likely autosomal

• When interpreting a pedigree chart of a family with a disease like muscular dystrophy, it is important to consider two steps. The first is to determine if the disorder is autosomal or X-linked.

• If the disorder is X-linked most of the males will have the disorder because the Y-chromosome cannot mask the affects of an affected X-chromosome. A female can have the disorder, but it would be a very low percentage. For a female to be affected, she would have had to receive an affected gene from both the mother and the father. This means that the father would have the disorder and the mother was a carrier.

• In an autosomal disorder, the disorder is not found on the X or Y chromosome. It is found on the other 22 chromosomes in the human body. This means that men and women have an equal chance of having the disorder.

Is it Autosomal or X-linked?

Autosomal because it affects males and females equally

Interpreting a Pedigree Chart

2. Determine whether the disorder is dominant or recessive.

– If the disorder is dominant, one of the parents must have the disorder.

– If the disorder is recessive, neither parent has to have the disorder because they can be heterozygous.

It is important to find out if a disorder is dominant or recessive. For example, Huntington’s disease is a dominant disorder. If you have only one dominant gene you will have Huntington’s disease, which is a lethal disorder. The disorder does not show up until a person is in their middle ages such as 45. It will quickly decrease their motor skills and the brain will begin to deteriorate.

• If a disorder is dominant, one parent must have the disorder (either homozygous dominant (TT) or heterozygous recessive (Tt). Both parents do not have to have the disorder. One parent might not have the disorder or be a carrier. If a disease is dominant, it does not skip a generation unless one parent is heterozygous dominant (Tt) and the other parent is homozygous recessive (tt). In this case the child has a chance of not receiving the dominant gene.

• If the disorder is recessive, a parent does not have to have the disorder, but could still pass it to their offspring. This would happen when a parent is heterozygous recessive (Tt) and passes on the recessive (t) gene. This means this disorder can skip generations. An example of a recessive disorder would be sickle cell anemia.

Dominant or Recessive?

It is dominant because a parent in every generation has the disorder. Remember if a parent in every generation has the disorder, the disorderhas not skipped a generation. If the disorder has not skipped a generation,the disorder is dominant.

Practice Analyzing Pedigrees

• http://www.zerobio.com/drag_gr11/pedigree/pedigree_overview.htm

Dominant or Recessive?

It is recessive, because a parent in every generation does not have the disorder. If a disorderSkips a generation, then the disorder is recessive. If a carrier is shown, it is recessive also.

DNADNA

RNARNA

ProteinProtein

Scientists call this the:

Central

Dogma of

Molecular

Biology!

DNA NucleotideDeoxyribose Nucleic Acid

OO=P-O O

Phosphate Group

NNitrogenous base (A, G, C, or T)

CH2

O

C1C4

C3 C2

5

Sugar(deoxyribose)

• James Watson and Francis Crick worked out the three-dimensional structure of DNA, based on work by Rosalind Franklin

Watson and Crick constructed a Model of DNA showing the double helix.

Figure 10.3A, B

DNA Double Helix

NitrogenousBase (A,T,G or C)

“Rungs of ladder”

“Legs of ladder”

Phosphate &Sugar Backbone

Chargaff’s Rule

• Adenine must pair with Thymine

• Guanine must pair with Cytosine

• Their amounts in a given DNA molecule will be about the same.

G CT A

DNA Double Helix

P

P

P

O

O

O

1

23

4

5

5

3

3

5

P

P

PO

O

O

1

2 3

4

5

5

3

5

3

G C

T A

DNA Nucleotides joined together Notice base pairing

A + T G + C

The Code of Life…

• The “code” of the chromosome is the SPECIFIC ORDER that bases occur. Proteins are built from the code.

A T C G T A T G C G G…

DNA Replication• DNA must be copied so new cells will

have complete instructions for making the RIGHT proteins.

• The DNA molecule produces 2 IDENTICAL new complementary strands following the rules of base pairing:

A-T, G-C

• Each strand of the original DNA serves as a template for the new strand

Each DNA molecule contains one original and one new complementary strand

DNA Replication• Complementary base pairs form new strands.

• …DNA control cell functions by serving as a template for PROTEIN structure.

• RNA uses base pairing, but the T is replaced with U for Uracil. A + U, G + C

• 3 Nucleotides = a triplet or CODON(which code for a specific AMINO ACID

• AMINO ACIDS are the building blocks of proteins.

• Proteins regulate cell activity and express traits controlled by genes.

Protein

DNA

Trait

DNA – Blueprint for Life

RNA – Ribosome – Amino Acid

Expresses Trait

Protein Synthesis – Building Proteins

DNA contains the instructions for the proteins that are needed for life. If the DNA does not replicate correctly, the wrong protein could be made.

DNA and RNA Comparison

DNA always STAYS in NucleusRNA is in nucleus during transcription, moves in cytoplasm, and on ribosome during translation.

Deoxyribose Ribose

A+TG+C

A+UG+C

Double Strand

Single Strand

Both have Phosphate

Table 14.2Types of RNA

Type of RNA Functions in Function

Messenger RNA(mRNA)

Nucleus, migratesto ribosomesin cytoplasm

Carries DNA sequenceinformation to ribosomes

Transfer RNA(tRNA)

Cytoplasm Provides linkage between mRNAand amino acids;transfers aminoacids to ribosomes

Ribosomal RNA(rRNA)

Cytoplasm Structural component of ribosomes

DNA makes RNA during Transcription

• DNA can “unzip” itself and RNA nucleotides match up to the DNA strand.

• Both DNA & RNA are formed from NUCLEOTIDES and are called NUCLEIC acids.

– The DNA is transcribed into RNA, which is translated into the polypeptide

Figure 10.6A

DNA

RNA

Protein

TRANSCRIPTION

TRANSLATION

• The information constituting an organism’s genotype is carried in its sequence of bases

Transcription produces genetic messages in the form of mRNA

Figure 10.9A

RNApolymerase

RNA nucleotide

Direction oftranscription

Newly made RNA

Templatestrand of DNA

• In transcription, DNA helix unzips

– RNA nucleotides line up along one strand of DNA, following the base-pairing rules

– single-stranded messenger RNA peels away and DNA strands rejoin

RNA polymerase

DNA of gene

PromoterDNA Terminator

DNAInitiation

Elongation

Termination

Area shownin Figure 10.9A

GrowingRNA

RNApolymerase

Completed RNA

Figure 10.9B

• Noncoding segments, introns, are spliced out

• A cap and a tail are added to the ends

Eukaryotic RNA is processed before leaving the nucleus

Figure 10.10

DNA

RNAtranscriptwith capand tail

mRNA

Exon Intron IntronExon Exon

TranscriptionAddition of cap and tail

Introns removed

Exons spliced together

Coding sequence

NUCLEUS

CYTOPLASM

Tail

Cap

RNA builds Proteins from Amino Acids during Translation

• The cell uses information from “messenger” RNA to produce proteins

mRNA leaves the nucleus to go to ribosome

rRNA and tRNA translateThe message to make proteins

tRNAAmino Acids

codon

Anti-codon

Proteins – Express Traits

• The “words” of the DNA “language” are triplets of bases called codons

• The codons in a gene specify the amino acid sequence of a polypeptide

• RNA Transcription copies the DNA onto mRNA.• Translation takes place in the cytoplasm on the

ribosomes.• tRNA picks up the correct amino acid and builds

a protein on the rRNA from the mRNA.

Translation of nucleic acids into amino acids

Types of RNA

• mRNA contains codons which code for amino acids.

3 LetterCode for amino acids

What amino acid will the code CAU make?

His

U C A G

U

C

A

G

GACU

GACU

GACU

GACU

UUUUUCUUAUUG

CUUCUCCUACUG

AUUAUCAUAAUG

GUUGUCGUAGUG

phe

leu

leu

ile

met (start)

val

UCUUCCUCAUCG

CCUCCCCCACCG

ACUACCACAACG

GCUGCCGCAGCG

ser

pro

thr

ala

UAUUACUAAUAG

CAUCACCAACAG

AAUAAC

AAGAAA

GAUGACGAAGAG

tyr

stopstop

his

gln

asn

lys

asp

glu

UGUUGCUGAUGG

CGUCGCCGACGG

AGUAGCAGAAGG

GGUGGCGGAGGG

cys

stoptrp

arg

ser

arg

gly

First Base T

hird Base

Second Base

Virtually all organisms share the same genetic code “unity of life”

64 possible combinations – 20 specific amino acids

What signals the ribosome to start translating the mRNA Into a new amino acid sequence and signals it to stop?

An initiation codon marks the start of an mRNA message

Figure 10.13A

End

Start of genetic message

AUG = methionine

• An exercise in translating the genetic code

Figure 10.8B

Startcodon

RNA

Transcribed strand

StopcodonTranslation

Transcription

DNA

Polypeptide

Proteins are built from chains of amino acids

DNA molecule

Gene 1

Gene 2

Gene 3

DNA strand

TRANSCRIPTION

RNA

Polypeptide

TRANSLATIONCodon

Amino acid

Ribosomes build polypeptides (chain of amino acids)

Figure 10.12A-C

Codons

tRNAmolecules

mRNA

Growingpolypeptide

Largesubunit

Smallsubunit

mRNA

mRNAbindingsite

P site A site

P A

Growingpolypeptide

tRNA

Next amino acidto be added topolypeptide

• mRNA, a specific tRNA, and the ribosome subunits assemble during initiation

Figure 10.13B

1

Initiator tRNA

mRNA

Startcodon Small ribosomal

subunit

2

P site

Largeribosomalsubunit

A site

Figure 10.14

1 Codon recognition

Amino acid

Anticodon

AsiteP site

Polypeptide

2 Peptide bond formation

3 Translocation

Newpeptidebond

mRNAmovement

mRNA

Stopcodon

Overview of Protein Synthesis

• Let’s look at it ONE more time!

Figure 10.15

1Stage mRNA istranscribed from aDNA template.

Anticodon

DNA

mRNARNApolymerase

TRANSLATION

Enzyme

Amino acid

tRNA

InitiatortRNA

Largeribosomalsubunit

Smallribosomalsubunit

mRNA

Start Codon

2Stage Each amino acid attaches to its proper tRNA with the help of a specific enzyme and ATP.

3Stage Initiation of polypeptide synthesis

The mRNA, the first tRNA, and the ribosomal subunits come together.

TRANSCRIPTION

Figure 10.15 (continued)

4Stage ElongationGrowingpolypeptide

Codons

5Stage Termination

mRNA

Newpeptidebondforming

Stop Codon

The ribosome recognizes a stop codon. The poly-peptide is terminated and released.

A succession of tRNAs add their amino acids to the polypeptide chain as the mRNA is moved through the ribosome, one codon at a time.

Polypeptide

Protein

DNA

Trait

DNA – Blueprint for Life

RNA – Ribosome – Amino Acid

Expresses Trait

1. Why is transcription necessary?Transcription makes messenger RNA (mRNA) to carry the code for proteins out of the nucleus to the ribosomes in the cytoplasm.

2. Describe transcription.RNA polymerase binds to DNA, separates the strands, then uses one strand as a template to assemble mRNA.

3. Why is translation necessary?Translation assures that the right amino acids are joined together by peptides to form the correct protein.

4. Describe translation.The cell uses information from mRNA to produce proteins. The tRNA brings the right amino acid to ribosome, rRNA to produce a specific amino acid chain that will later become an active protein.

5. What are the main differences between DNA and RNA.DNA has deoxyribose, RNA has ribose; DNA has 2 strands, RNA has one strand; DNA has thymine, RNA has uracil.

6. Using the chart on page 303, identify the amino acids coded for by these codons: UGG CAG UGCtryptophan-glutamine-cysteine

Genetic Disorders

Genetic DisordersAutosomal Recessive

Both parents Must be Carriers Nn X Nn

Normal = Nnn = cystic fibrosis

Sickle Cell Anemia

Autosomal recessiveBoth parents must be carriers To pass to children.Nn X NnOr one is carrier and other has condition. Nn x nn

Would not show in parents ifCarriers

Tay-Sachs

Autosomal Recessive

Huntingdon’s Disease

Autosomal Dominant

What Are Mutations?

• Changes in the nucleotide sequence of DNA

• May occur in somatic cells (body cells,aren’t passed to offspring)

• May occur in gametes (eggs & sperm) and be passed to offspring

• May be chromosomal or gene mutations.

Protein

DNA

Gene

Trait

DNA – If there is a mutation in the DNA strand, then the RNA strand will be changed

If the mRNA brings the wrong instructions, may result in wrong protein – Ribosome – Amino Acid

Expresses TraitMutation – wrong protein

Many mutations do not change the amino acid, so NO mutation will occur.

Protein Translation

• Modified genetic code is “translated” into proteins

• Codon code is specific, but redundant!– 20 amino acids– 64 triplet (codon) combinations

Which is why some mutations don’t matter!

Gene Mutations

• Change in the nucleotide sequence of a gene

• May only involve a single nucleotide

• May be due to copying errors, chemicals, viruses, etc.

Point Mutation• Change of a single

nucleotide• Includes the deletion,

insertion, or substitution of ONE nucleotide in a gene

• Sickle Cell disease is the result of one nucleotide substitution

• Occurs in the hemoglobin gene

Frameshift Mutation• Inserting or deleting one or more nucleotides

• Changes the “reading frame” like changing a sentence

• Proteins built incorrectly

Example of Sickle Cell mutation

Normal hemoglobin DNA

mRNA

Normal hemoglobin

Glu

Mutant hemoglobin DNA

mRNA

Sickle-cell hemoglobin

Val

• Illustration of mutations

Figure 10.16B

mRNA

NORMAL GENE

BASE SUBSTITUTION

BASE DELETION

Protein Met Lys Phe Gly Ala

Met Lys Phe Ser Ala

Met Lys Leu Ala His

Missing

Figure 8.23A, B

Deletion

Duplication

Inversion

Homologouschromosomes

Reciprocaltranslocatio

n

Nonhomologouschromosomes

• Chromosomal changes can be large or small

Chromosome Mutations• May Involve:

– Changing the structure of a chromosome

– Can cause abnormal development of offspring. of part

Deletion

• Due to breakage• A piece of a chromosome is lost

Inversion

• Chromosome segment breaks off

• Segment flips around backwards

• Segment reattaches

Duplication

• Occurs when a gene sequence is repeated

Translocation

• Involves two chromosomes that aren’t homologous

• Part of one chromosome is transferred to another chromosomes

Nondisjunction• Failure of chromosomes to separate during meiosis

• Causes gamete to have too many or too few chromosomes

• Disorders:– Down Syndrome – three 21st chromosomes– Turner Syndrome – single X chromosome– Klinefelter’s Syndrome – XXY chromosomes

Normal Male Karotype

962n = 46

Normal Female Karotype

972n = 46

Male, Trisomy 21 (Down’s)

982n = 47Can you spot the problem?

Female Down’s Syndrome

992n = 47

Klinefelter’s Syndrome

1002n = 47

Genetic Engineering

• Evaluate the scientific and ethical issues associated with gene technologies.

• Genetic Engineers refers to the alteration of an organism’s genes for practical purposes.

• Recombinant DNA

• Transgenic Organisms

• Cloning

• Stem Cell Research

• Gel Electrophoresis/DNA fingerprinting

Recombinant Bacteria1. Remove bacterial DNA (plasmid).

2. Cut the Bacterial DNA with “restriction enzymes”.

3. Cut the DNA from another organism with “restriction enzymes”.

4. Combine the cut pieces of DNA together with another enzyme and insert them into bacteria.

5. Reproduce the recombinant bacteria.

6. The foreign genes will be expressed in the bacteria.

Benefits of Recombinant Bacteria

1. Bacteria can make human insulin or human growth hormone.

2. Bacteria can be engineered to “eat” oil spills.

Recombinant DNA

• The ability to combine the DNA of one organism with the DNA of another organism.

• Recombinant DNA technology was first used in the 1970’s with bacteria.

Genetically modified organisms are called transgenic organisms.

TRANSGENIC ANIMALS

1. Mice – used to study human immune system

2. Chickens – more resistant to infections

3. Cows – increase milk supply and leaner meat 4. Goats, sheep and pigs – produce human proteins in their milk

Human DNA in a Goat Cell

This goat contains a human gene that codes for a blood clotting agent. The blood clotting agent can be harvested in the goat’s milk.

.

Transgenic GoatCarries a foreign gene that has been inserted into its genome.

Desired DNA is

added to an egg cell.

How to Create a Transgenic Animal

The DNA of plants and animals can also be altered.

PLANTS

1. disease-resistant and insect-resistant crops

2. Hardier fruit

3. 70-75% of food in supermarket is genetically modified.

How to Create a Genetically Modified Plant

1.Create recombinant bacteria with desired gene.

2. Allow the bacteria to “infect" the plant cells.

3. Desired gene is inserted into plant chromosomes.

DNA Cloning

• Transfer of DNA fragment from one organism to a self-replicating genetic element such as bacterial plasmid

Reproductive Cloning

• Generate an animal that has the same nuclear DNA as another existing animal.

Therapeutic Cloning

• Also called “embryo cloning”, is the production of human embryos for use in research.

• Stem Cell Collection:• Are unspecialized cells

capable of renewing themselves through cell division.

• Under certain experimental conditions, they can be induced to become tissue or organ specific cells with special functions.

What do you think about eating genetically modified foods?

Polymerase Chain ReactionPCR

• PCR allows scientists to make many copies of a piece of DNA.

1. Heat the DNA so it “unzips”.

2. Add the complementary nitrogenous bases.

3. Allow DNA to cool so the complementary strands can “zip” together.

Steps Involved in Gel Electrophoresis

1. “Cut” DNA sample with restriction enzymes.

2. Run the DNA fragments through a gel.

3. Bands will form in the gel.

4. Everyone’s DNA bands are unique and can be used to identify a person.

5. DNA bands are like “genetic fingerprints”.