genetic engineering

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GENETIC ENGINEERING

By,Dr. Priyanka SharmaII year MDSDepartment of Public Health DentistryJSS Dental College & Hospital

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CONTENTS1) INTRODUCTION2) BASICS OF GENETIC ENGINEERING3) HISTORY OF GENETIC ENGINEERING4) GENERAL APPLICATION OF GENETIC

ENGINEERING5) GENETIC ENGINEERING IN

DENTISTRY - VARIOUS TECHNIQUES OF GENETIC ENGINEERING

6) GENETIC COUNSELLING & ROLE OF DENTIST

7) SUMMARY8) CONCLUSION9) REFERENCES

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CONTENTS1)INTRODUCTION2) BASICS OF GENETIC ENGINEERING3) HISTORY OF GENETIC ENGINEERING4) GENERAL APPLICATION OF GENETIC

ENGINEERING5) GENETIC ENGINEERING IN

DENTISTRY - VARIOUS TECHNIQUES OF GENETIC

ENGINEERING6) GENETIC COUNSELLING & ROLE OF

DENTIST7) SUMMARY8) CONCLUSION9) REFERENCES

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INTRODUCTIONGenetic engineering is a part of

biotechnology.

Biotechnology is the use of living systems and organisms to develop or make useful products, or "any technological application that uses biological systems, living organisms or derivatives thereof, to make or modify products or processes for specific use" (UN Convention on Biological Diversity, Art. 2).

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INTRODUCTION continuation..

Biotechnology is a huge topic. Its hard to define its exact boundaries. Some European scientists divide the field into :

1) Red biotechnology

2) Green biotechnology Some divides it into :

1) White2) Blue Biotechnology falls under many umbrellas

which is basically considered as life science.

Book : Biotechnology & Genetic engineering (Kathy wilson peacock) 2010,Edi:1 : Page No. 4 (Chapter 1)

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Biotechnology

Biology & Zoology

Cell biology

Microbiology

Molecular Biology

Physiology, Ecology, Embryology

Genetics, Population genetics,

Epigenetics

Proteonomics & Bioinformatics

Book : Biotechnology & Genetic engineering

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INTRODUCTION continuation..

• Genetics – science of genes, heredity and variation in living organisms.

• Genetics deals with the molecular structure and function of genes, and gene behavior in context of a cell or organism (e.g. dominance and epigenetics ).

• Patterns of inheritance from parent to offspring, and gene distribution, variation and change in populations = Population genetics.

Book : Genetics and the Organism: Introduction

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INTRODUCTION continuation..

EssenceOf

Genetics

•Chromosome•Packaged and organized chromatin, a complex of macromolecules

found in cells, consisting of DNA, protein and RNA.

EssenceOf

Genetics

•DNA•A molecule that encodes the genetic instructions used in the

development and functioning of all known living organisms and many viruses.

EssenceOf

Genetics

•Genetic Variation•Permanent change in the chemical structure of genes brought about

by mutation, important in providing genetic material for natural selection.

EssenceOf

Genetics

•Heredity•The study of heredity in biology is called genetics, which includes

the field of epigenetics.

Book : Genetics and the Organism: Introduction

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9U S National Library of Medicine

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A form – 11 bp/ turn

B form-10 bp/ turn

Z form-12 bp/ turn

From Lippincotts - Illustrated Biochemistry

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Deletion Inversion Duplication

Insertion Translocation

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INTRODUCTION continuation..Various Branches of Genetics

Behavioural genetics

Classical genetics

Developmental genetics

Conservationgenetics

Ecological genetics Evolutionary

genetics

Genetic engineering

& Metagenesis

Book : Genetics and the Organism: Introduction

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CONTENTS1) INTRODUCTION

2) BASICS OF GENETIC ENGINEERING

3) HISTORY OF GENETIC ENGINEERING4) GENERAL APPLICATION OF GENETIC ENGINEERING5) GENETIC ENGINEERING IN DENTISTRY

- VARIOUS TECHNIQUES OF GENETIC ENGINEERING

6) ETHICAL ISSUES7) SUMMARY8) CONCLUSION9) REFERENCES

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BASICS OF GENETIC ENGINEERING

• Different terms used for genetic engineering :

1) Gene manipulation2) Gene cloning3) Recombinant DNA technology4) Genetic modification5) New genetics

An Introduction to Genetic Engineering (Desmond S. T. Nicholl) Edi :3rd 2008Chapter 2 . Page 3

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Direct manipulation of an organism's genome using biotechnology .

First isolating and copying the

genetic material of interest

using molecular cloning methods

Generate a DNA sequence

New DNA  inserted in the host

genome

BASICS OF GENETIC ENGINEERING CONTINUATION..

An Introduction to Genetic Engineering (Desmond S. T. Nicholl) Edi :3rd 2008 Chapter 2.

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17Miller et al(2000).  An Introduction to Genetic Analysis (7th ed.).

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18CONTENTS1) INTRODUCTION2) BASICS OF GENETIC ENGINEERING3) HISTORY OF GENETIC ENGINEERING4) GENETIC ENGINEERING IN DENTISTRY - VARIOUS TECHNIQUES OF GENETIC ENGINEERING5)GENETIC COUNSELLING AND ROLE OF A DENTIST5) SUMMARY6) CONCLUSION7) REFERENCES

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Genetic inheritance was first discovered by Gregor Mendel in 1865 following experiments crossing peas.

• Although largely ignored for 34 years he provided the first evidence of hereditary segregation and independent assortment

In 1889 Hugo de Vries came up with the name "(pan)gene" for after postulating that particles are responsible for inheritance of characteristics

Term "genetics" was coined by William Bateson in 1905.

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In 1928 Frederick Griffith proved the existence of a "transforming principle" involved in inheritance, which Avery, MacLeod and McCarty later (1944) identified as DNA.

Edward Lawrie Tatum and George Wells Beadle developed the central dogma that genes code for proteins in 1941. 

The double helix structure of DNA was identified by James Watson and Francis Crick in 1953.

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In 1970 Hamilton Smiths lab discovered restriction enzymes that allowed DNA to be cut at specific places and separated out on an electrophoresis gel. • This enabled scientists to isolate genes from

an organism's genome.

DNA ligases, that join broken DNA together, had been discovered earlier in 1967 and by combining the two enzymes it was possible to "cut and paste" DNA sequences to create recombinant DNA.

Plasmids, discovered in 1952, became important tools for transferring information between cells and replicating DNA sequences.

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Frederick Sanger developed a method for sequencing DNA in 1977, greatly increasing the genetic information available to researchers

Polymerase chain reaction (PCR), developed by Kary Mullis in 1983, allowed small sections of DNA to be amplified and aided identification and isolation of genetic material

Artificial competence was induced in Escherichia coli in 1970 when Morton Mandel and Akiko Higa showed that it could take up bacteriophage λ after treatment with calcium chloride solution (CaCl2).

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Two years later, Stanley Cohen showed that CaCl2 treatment was also effective for uptake of plasmid DNA.

Transformation using electroporation was developed in the late 1980s, increasing the efficiency and bacterial range

In 1972 Paul Berg utilised restriction enzymes and DNA ligases to create the first recombinant DNA  molecules. 

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Herbert Boyer and Stanley N. Cohen took Bergs work a step further and introduced recombinant DNA into an bacterial cell. 

In 1981 the laboratories of Frank Ruddle, Frank Constantini and Elizabeth Lacy injected purified DNA into a single-cell mouse embryo and showed transmission of the genetic material to subsequent generations.

On June 19, 2013 the leaders of three research teams who originated the technology, Robert T. Fraley of Monsanto; Marc VanMontagu of Ghent University in Belgium and founder of Plant Genetic Systems and CropDesign ; and Mary-Dell Chilton of Washington University in St. Louis and Syngenta were awarded with the World Food Prize

Gordon, J.; Ruddle, F. (1981). "Integration and stable germ line transmission of genes injected into mouse pronuclei". Science 214 (4526): 1244.

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The first recorded knockout mouse was created by Mario R. Capecchi, Martin Evans and Oliver Smithies in 1989. They are used to study gene function and make useful models of human diseases.

In 1992 onco-mice with tumor suppressor genes knocked out were generated.Creating Knockout rats are much harder and has only been possible since 2003

Bacteria synthesising human insulin were developed in 1979, being used as a treatment for the first time in 1982

Zan, Y; Haag, J. D.; Chen, K. S.; Shepel, L. A.; Wigington, D; Wang, Y. R.; Hu, R; Lopez-Guajardo, C. C.; Brose, H. L.; Porter, K. I.; Leonard, R. A.; Hitt, A. A.; Schommer, S. L.; Elegbede, A. F.; Gould, M. N. (2003). “Production of knockout rats using ENU mutagenesis and a yeast-based screening assay". Nature Biotechnology 21(6): 645–51.

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In 1988 the first human antibodies were produced in plants.

The first animal to synthesise transgenic proteins in their milk were mice, engineered to produce human tissue plasminogen activator.

With the discovery of microRNA in 1993

came the possibility of using RNA interference to silence an organisms endogenous genes

- Peng, S. (2006). "A transgenic approach for RNA interference-based genetic screening in mice".  Proceedings of the National Academy of Sciences 103 (7): 2252–2220.- Vaucheret, H.; Chupeau, Y. (2011). plant miRNAs regulate gene expression in animals Cell Research 22 (1): 3–5. 

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Improved our understanding of genetics.

His research helped to make organ transplantations possible.

Dr. Bernard Amos

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• His work cloned frogs

laid the foundations

for somatic cell

nuclear transfer, the

application of which

led to Dolly the sheep.

John Gurdon

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Worked out the Structure of

Proteins.

Linus Pauling

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“The Father of Cloning”

Hans Spermann

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“The Father of Genetics”

Gregor Mendel

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• He noticed that there is a pattern in the 4 bases: Adenine, Guanine, Cytosine and Thymine.

• A=T and G=C.

Erwin Chargaff

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In 1973 created a transgenic mouse by introducing foreign DNA into its embryo, making it the world’s first transgenic animal.

Rudolf Jaenisch 

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CONTENTS1) INTRODUCTION2) BASICS OF GENETIC ENGINEERING3) HISTORY OF GENETIC ENGINEERING4) GENERAL APPLICATION OF

GENETIC ENGINEERING5) GENETIC ENGINEERING IN

DENTISTRY - VARIOUS TECHNIQUES OF GENETIC ENGINEERING

6) 5)GENETIC COUNSELLING AND ROLE OF A DENTIST

7) SUMMARY8) CONCLUSION9) REFERENCES

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GENERAL APPLICATIONS OF GENETIC ENGINEERING

][38]

Eg: transgenic plants produce natural pesticide to resist to pest

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Engineered Mammals

A monkey named ANDi, for "inserted DNA", in a picture released in January 2001. ANDi was born in October 2000 at the Oregon Health Science University after receiving an extra bit of genetic material to become the world's first genetically modified non-human primate

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Cloning Dolly• Sheep A: donate body cell nucleus • Sheep B: donate an egg cell without nucleus• Sheep C: surrogate mother

A CB Dolly

Who’s its mother?

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38CONTENTS1) INTRODUCTION2) BASICS OF GENETIC ENGINEERING3) HISTORY OF GENETIC ENGINEERING4) GENERAL APPLICATION OF GENETIC

ENGINEERING5) GENETIC ENGINEERING IN

DENTISTRY - VARIOUS TECHNIQUES OF GENETIC ENGINEERING

6) 5)GENETIC COUNSELLING AND ROLE OF A DENTIST

7) SUMMARY8) CONCLUSION9) REFERENCES

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GENETICS & ORAL HEALTH39

GENETICS

Craniofacial & Tooth

morphogenesisAgenesis

Dental caries

Periodontistis

Cleft lip & Palate

MalocclusionOral Cancer

Pharmacogenetics

Behavorial Genetics

Genetic disorders /

Abnormalities

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TECHNIQUES OF

GENETIC ENGINEERING

Tools and techniques

Methods in recombinant DNA

technology

Genetically modified organisms

Genetic treatments

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TECHNIQUES OF

GENETIC ENGINEERING

Tools and techniques

Methods in recombinant DNA

technology

Genetically modified organisms

Genetic treatments

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TOOLS & TECHNIQUES

DNA: The Raw Material– Heat-denatured DNA

• DNA strands separate if heated to just below boiling• Exposes nucleotides• Can be slowly cooled and

strands will renature

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Restriction Endo-nucleases

• Enzymes that can clip strands of DNA

crosswise at selected positions

• Each has a known sequence of

4 to 10 pairs as its target

• Can recognize and clip at palindromes

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• Can be used to cut DNA in to smaller pieces for further study or to remove and insert sequences.

• Can make a blunt cut or a “sticky end”• The pieces of DNA produced are

called restriction fragments.• Differences in the cutting pattern of specific

restriction endonucleases give rise to restriction fragments of differing lengths- restriction fragment length polymorphisms.

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Ligase and Reverse Transcriptase

• Ligase: Enzyme necessary to seal sticky ends together

• Reverse transcriptase: enzyme that is used when converting RNA into DNA.

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ANALYSIS OF DNA

Gel electrophoresis

Polymerase Chain Reaction

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49Gel electrophoresis: produces a readable

pattern of DNA fragments

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GEL ELCTROPHORESIS• APPLICATIONS:Estimation of the size of DNA

molecules following restriction enzyme digestion, e.g. in restriction mapping of cloned DNA.

Analysis of PCR products, e.g. in molecular genetic diagnosis or genetic fingerprinting.

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51POLYMERASE CHAIN REACTION: A MOLECULAR XEROX MACHINE

FOR DNA• Some techniques to analyze DNA and

RNA are limited by the small amounts of test nucleic acid available

• Polymerase chain reaction (PCR) rapidly increases the amount of DNA in a sample

• So sensitive- could detect cancer from a single cell

• Can replicate a target DNA from a few copies to billions in a few hours

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Three Basic Steps that Cycle• Denaturation

– Heat to 94°C to separate in to two strands– Cool to between 50°C and 65°C

• Priming– Primers added in a concentration that favors binding to

the complementary strand of test DNA– Prepares the two strands (amplicons) for synthesis

• Extension– 72°C– DNA polymerase and nucleotides are added– Polymerases extend the molecule

• The amplified DNA can then be analyzed

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54Methods Used to Size, Synthesize,

and Sequence DNA

• Relative sizes of nucleic acids usually denoted by the number of base pairs (bp) they contain.

• DNA Sequencing: Determining the Exact Genetic Code– Most detailed information comes from the

actual order and types of bases- DNA sequencing

– Most common technique: Sanger DNA sequence technique

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56Nucleic Acid Hybridization and

Probes• Two different nucleic acids can hybridize by uniting at

their complementary regions.

• Gene probes: specially formulated oligonucleotide tracers– Short stretch of DNA of a known sequence– Will base-pair with a stretch of DNA with a complementary

sequence if one exists in the test sample

• Can detect specific nucleotide sequences in unknown samples.

• Probes carry reporter molecules (such as radioactive or luminescent labels) so they can be visualized.

• Southern blot- a type of hybridization technique

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57Blotting Methods

• Southern blotting involves the transfer of DNA from a gel to a membrane, followed by detection of specific sequences by hybridization with a labeled probe.

• Northern blotting, RNA is run on a gel.

• Western blotting entails separation of proteins on an SDS gel, transfer to a nitrocellulose membrane, and detection proteins of interest using antibodies.

58FIGURE 21: Southern blot: Identifying Specific DNA Fragments(Edward Southern--the pioneer)

or gentle vacuum pressure

Drying or exposure to UV light

Probes: Isotope or chemical

Gel is soaked in alkali buffer to denature DNA

Northern blotting is similar to Southern blotting, but involves the transfer of RNA from a gel to a membrane

RNA

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Northern blotting: Measuring gene activity

Poly(A)+ RNA: from rat tissuesProbe: G3PDH (glyceraldehyde-3-phosphate dehydrogenase)

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Western blotting

• Western blotting entails separation of proteins on an SDS gel, transfer to a nitrocellulose membrane, and detection proteins of interest using antibodies.

wikipedia

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Western blot 62

Blotting Methods

• Antibodies can recognize the protein of interest or an epitope tag.

• epitope tag – A short peptide sequence that encodes a recognition site (“epitope”) for an antibody, typically fused to a protein of interest for detection or purification by the antibody.

Human influenza hemagglutinin (HA): YPYDVPDYA

The HA tag is derived from the HA-molecule corresponding to amino acids 98-106 has been extensively used as a general epitope tag in expression vectors.

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Probes Used for Diagnosis 64

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65Fluorescent in situ Hybridizaton

(FISH)

• Probes applied to intact cells• Observed microscopically for the

presence and location of specific genetic marker sequences

• Effective way to locate genes on chromosomes

DNA Microarrays

• Gene expression array are used to detect the level of all the expressed genes in an experimental sample.

• SNP arrays permit genome-wide genotyping of single nucleotide polymorphisms. =>use allele-specific oligonucledtide probe

• Array comparative genome hybridization (array-CGH) allows the detection of copy number changes in any DNA sequence compared between two samples.

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67DNA Microarrays

• DNA microarrays comprise known DNA sequences spotted or synthesized on a small chip.

Microarrays show the levels of all the

expressed genes in an experimental sample.

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TECHNIQUES OF

GENETIC ENGINEERING

Tools and techniques

Methods in recombinant DNA

technology

Genetically modified organisms

Genetic treatments

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69 Methods in Recombinant DNA Technology

• Primary intent of recombinant DNA technology- deliberately remove genetic material from one organism and combine it with that of a different organism.

• Form genetic clones– Gene is selected– Excise gene– Isolate gene– Insert gene into a vector– Vector inserts DNA into a cloning host

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70 Methods in Recombinant DNA Technology

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71Technical Aspects of Recombinant

DNA and Gene Cloning• Strategies for obtaining genes in an

isolated state– DNA removed from cells, separated into

fragments, inserted into a vector, and cloned; then undergo Southern blotting and probed

– Gene can be synthesized from isolated mRNA transcripts

– Gene can be amplified using PCR• Once isolated, genes can be maintained in

a cloning host and vector (genomic library)

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72Characteristics of Cloning

Vectors• Capable of carrying a significant piece of the

donor DNA• Readily accepted by the cloning host• Must have a promoter in front of the cloned

gene• Vectors (such as plasmids and bacteriophages)

should have three important attributes:– An origin of replication somewhere on the vector– Must accept DNA of the desired size– Contain a gene that confers drug resistance to

their cloning host

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74Characteristics of Cloning Hosts

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APPLICATIONS OF

GENETIC ENGINEERINGTools and techniquesMethods in recombinant DNA

technologyGenetically modified organisms

Genetic treatments

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TREATMENT OF GENETIC DISEASE

• Conventional approach

• Gene Therapy

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• Enzyme induction by drugs• Replacement of deficient enzymes /

proteins• Replacement of deficient vitamin / co-

enzyme• Replacement of deficient product• Substrate restriction in diet• Drug therapy• Drug avoidance• Replacement of diseased tissue• Removal of disease tissue

CONVENTIONAL APPROACH OF TREATMENT

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78Genomic medicine

use of genotypic analysis (DNA testing) to enhance quality of medical care, including

- presymptomatic identification

- preventive intervention

- selection of pharmacotherapy

- design of medical care

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GENE THERAPYReplacement of a deficient gene /

gene product or correction of an abnormal gene.

2 TYPES:i. Germ-line gene therapy – changes

will be passed on to subsequent generations

ii. Somatic Cell gene therapy – changes will not be passed on to future generations

Gene Therapy

• Gene transfer for the purpose of treating human disease.

• Transfer of new genetic material as well as manipulation of existing genetic material.

(Genetic engineering)

in vivo ex vivo

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Potential Uses

• Treatment of recurrent disease

• Adjuvant treatment

• Localized distant metastatic disease

Gene therapy 82

Delivery systems / vectors Non – viral- Electropolation- DEAE-dextran- Calcium phosphate- Liposomes-Naked DNA

VirusesRetrovirusesAdenovirusesAdeno-associated virusesHerpes virus

Gene therapy83

Gene therapy 84

Gene therapy in dentistry1. Bone repair• Mesenchymal stem –cell mediated gene therapy (BMPs)• Using adenoviral vector• Transfer of Platelet derivative growth

factor (PDGF)• Bone sialoprotein delivery (in-vivo)

2. Salivary glands• Irreversible salivary gland dysfunction

Gene therapy85

• Adenovirus encoding human AQP1(water channel protein) – irradiated salivary gland hyposalivation.

• Autoimmune diseases Sjogren syndrome : cytokines inflammation adeno-associated virus, AAV, serotype2 IL-10 transfer using recombinant AAV2 vector –

salivary glands hyposalivation .

Gene therapy86

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Gene therapy87

• Gene therapeutics

local (exocrine) systemic (endocrine) (oral, pharyngeal, (single protein & esophageal) deficiency) Eg mucosal cadidiasis Eg hGH• Azole resistant• Recombinant adenoviral vector encoding H3

Gene therapy88

• Pain Virus vector – mediated transfer of genes

encoding opiate peptides

peripheral & central neurons

Anti-noceptive effects

Direct gene delivery – articular surface TMJ

Gene therapy89

• Keratinocytes Gene therapy – systemic

human aplipoprotein E, factor IX,

growth hormone and IL-10 into

bloodstream.

• DNA vaccinations

Gene therapy90

• Gene gun-based DNA vaccination against

infectious diseases – oral mucosa

(Wang J 2003)• Caries vaccine

Gene therapy91

• Subunit Vaccines - synthetic peptide vaccines - recombinant vaccines

• Conjugate Vaccines • Routes to Protective Responses - oral - intranasal - tonsillar - rectal • Adjuvants and Delivery Systems Cholera & E coli, microcapsules, liposomes

Gene therapy92

Human applications - Active immunization ( 7 trials)

- Passive immunization ( cow’s milk,

chicken eggs, transgenic plant antibody)

Gene therapy93

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Future Strategies of Gene Therapy in Preventing Periodontal Diseases

• Gene Therapeutics-Periodontal Vaccination

• Genetic Approach to Biofilm Antibiotic Resistance

• An In vivo Gene Transfer by Electroporation for Alveolar Remodelling

• Tight Adherence Gene for the Control of Periodontal Disease Progression

• Antimicrobial Gene Therapy to Control Disease Progression

Gene therapy94

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Gene therapy95

• AIDS vaccine• HPV vaccine• HSV vaccine

Head & neck cancer

Gene therapy96

Mechanism Goal Development stage

Oncogene down-regulation therapy

Delete defective gene

Inhibit tumor cell growth

Pre-clinical

Gene addition therapy

Add tumor suppressor gene

Kill tumor cell Clinical trial

Anti-sense RNA

Abrogate genes stimulating tumor growth

Inhibit tumor cell growth

Clinical trial

Immunotherapy

Enhance immune surveillance

Enhance immunogenicity of tumor cell

Clinical trial

Current gene therapies for cancer 97

Anti-angiogenesis therapy

Transfer gene to tumor cells to block angiogenesis

Inhibit tumor progression

Pre-clinical

Drug resistance gene therapy

Transfer cytoprotective gene

Decrease toxicity of chemotherapy

Clinical trial

Tumor-cell killing viruses

Introduce viruses that destroy tumor cells as part of replication cycle

Kill tumor cells

Pre-clinical

Suicide gene therapy

Transfer gene encoding pro-drug activating enzyme

Kill tumor cell & enhance chemotherapy

Clinical trial98

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99HUMAN GENOME PROJECT

Objectives:i. Sequencing of human genomesii. Mapping of human inherited diseasesiii. Development of new DNA

technologiesiv. Development of bio-informaticsv. Comparitive Genomicsvi. Functional Genomics

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TISSUE ENGINEERING

• Tissue Engineering is a general name of biomedical fields to enable cells to enhance their proliferation, differentiation, and morphological organization for induction of tissue regeneration, resulting in regenerative medical therapy of diseases.

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Stem cells in regenerative medicine

• A stem cell is defined as a cell that can continuously produce unaltered daughters and, furthermore, has the ability to generate cells with different and more restricted properties.

• These cells can either multiply (progenitors or transit amplifying cells) or be committed to terminal differentiation.

• Stem cells are self-renewing and thus can generate any tissue for a lifetime.

• This is a key property for a successful therapy.

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GENETIC COUNSELLING

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GENETIC COUNSELLINGA process of communication and education which

addresses concerns relating to the development and / or transmission of a hereditary disorder.

STEPS IN GENETIC COUNSELLING- Diagnosis- Risk assessment- Communication- Discussion of options- Long term contact & support

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DIAGNOSIS

• History• Examination• Investigation • Only when accurate diagnosis is possible• When etiological heterogeneity is present

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The good side of the coin should also be emphasized

RISK ASSESSMENT

ARBITRARY GUIDE

1 in 10 - High risk 1 in 20 - Low risk Intermediate values - Moderate risk

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LONG TERM CONTACT & SUPPORT

• Counselling centers should maintain informal contact with families through a network of genetic associates

• Genetics registers provide a useful means in ensuring effective contact

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111NEONATAL SCREENING

To prevent subsequent morbidity

POPULATION CARRIER SCREENING

The branch of medical genetics which is concerned with screening and the prevention of genetic disease on a population basis is known as community genetics.

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112PRENATAL DIAGNOSISAbility to detect abnormality in an

unborn child.

TECHNIQUESI. Non invasive

- Maternal Serum screening

- Ultra sound

II. Invasive

- Amniocentesis

- Chorionic Villus Sampling

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113INDICATIONS FOR PRENATAL DIAGNOSIS

• Advanced maternal age• Previous child with a genetic

abnormality• Family History of

- Chromosome abnormality- Single gene disorder- Neural tube defect- Other congenital structural abnormalities

• Abnormalities identified in pregnancy Eg. Poor fetal growth

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114• Other High risk factors

- Parental Consanguinity- Poor obstetric history

Eg: Recurrent miscarriagesPrevious unexplained

still birth- Maternal illness

Eg: Poorly controlled IDDMMaternal epilepsy Treatment with Sodium Valproate

IDENTIFY GENETIC DISEASE

1. Build the pedigree

2. Analyse

3. Risk of recurrence

4. Decision

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Role of dentist as genetic counselor

• Oral manifestations

• Correct identification

• Diagnosis

• Referral

• Suggestion

• Screening for dental diseases

DNA probes

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• Bioengineering

• Nanodentistry

• Biomimetics

• Molecular Epidemiology ( Variation Genetics )

Future prospects117

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SUMMARY

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Genetic engineering

Enabling technology

Cutting,modifying and joining DNA

molecules

enzymes

Generation of DNA

fragments

Restriction enzyme DNA Ligase

Joining to a vector or DNA

Molecule

Introduction into the host

cell

Selection of desired

sequence

Gene cloningRecombinant

DNAMolecular cloning

Pure science, Biotechnology,

Medicine, Dentistry

Legal and ethical

considerations

Microbial & Molecular genetics

In 1972Stanford

University

Is also known as

Has application in

But raises some

Arose from

was first achieved

Is an

That involves

using

Such as

Requires four steps

Can be used for

used for

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CONCLUSION

• Biotechnology as a fast developing technology as well as science , has already shown its impact on different aspects of day-to-day human life such as public health pharmaceuticals, food and agriculture industries, bioenergetics and information technology.

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• As it has potential to ensure food security, dramatically reduce hunger and malnutrition and reduce rural poverty , particularly in developing countries , Now it is very clear that biotechnology is the key technology for the 21st century and the science of the future.

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References1. Colin EC. What Is Genetics? In: Colin EC. Elements of Genetics.

3rd ed. New York: McGraw Hill Book Company, Inc; 1956. p. 1-3.2. Auden WH. History of Human Genetics. In: Motulsky V. Human

Genetics, Problems and Approaches. 3rd ed. New York: Springer; 1997. p. 1-22.

3. Dhar PK. Genetics in pediatric dentistry. In: Tandon S. Textbook of Pedodontics. Ist ed. Hyderabad: Paras Medical Publisher; 2001. p. 614-622.

4. Baeudet AL. Genetics and Disease. In: Fauci, Braunwald, Isselbacher, Wilson, Martin, Hauser, Longo. Harrison’s Principles of Internal Medicine. Vol 2. 14th ed. New York: McGraw Hill Companies, Inc; 1998. p. 365-395.

5 Tortora GJ, Grabowski SR. Cellular level of organization. 10th ed. John wiley & sons, USA. 84-97.

6 Pashayan HM, Feingold M. Selected syndromes in pedodontics. White GE. Clinical oral pediatrics. Quintessence International. Tokyo. 1981. ed. 73-80.

7 Joerde LB, Carey JC, White RL. Genetic Variation: Its Origin and Detection. In: Joerde LB, Carey JC, White RL. Medical Genetics. Ist ed. Toronto: Mosby; 1995. p. 30-56.

8 Tencate AR et al. Development of tooth and its supporting structures. In: Nanci A. Tencate’s oral histology. 8thed. Mosby. 2003: 79-110.

9 Tandon S, Bhat S. Developing dentition and its disturbances. In: Tandon s. Textbook of pedodontics. Ed. Paras publishing . 2001. 85-105.

10. Shafer. Textbook of oral pathology. 4th ed. Harcourt Asia PTE Ltd.. 1999.

11 Anderson M. Risk Assessment and Epidemiology of Dental Caries: Review of Literature. Pediatr Dent 2002; 24(5): 377-385.

12 Sofaer JA. Host genes and dental caries. Br Dent J 1993; 175: 403-409.

13 Shuler Cf. Inherited risks for susceptibility to dental caries. J Dent Educ 2001; 65(10): 1038-1045.

14. Hart TC & Kornman KC. Genetic factors in pathogenesis of periodontitis. Periodont 2000 1997; 14: 202-15.

15 Michalowicz. Genetic & heritable risk factors in periodontal disease. J Periodontol 1994; 65: 479-88.

16 Cobourne MT. the complex genetics of cleft lip & palate. Euro J Ortho 2004; 26: 7-16.

17 Mossey PA et al. The heritability of malocclusion. The influence of genetics in malocclusion. Br J Ortho 1999; 26: 195-203.

18 Partridge M. Oral cancer: the genetic basis of disease. Dent Update 2000; 27: 242-248.

19 Carrozzo M. Hepatitis C virus-associated oral lichen planus: is the geographical heterogeneity related to HLA-DR6?J Oral Pathol Med. 2005 Apr;34(4):204-8.

20 Lawson CAet al. Analysis of the insertion/deletion related polymorphism within T cell antigen receptor beta variable genes in primary Sjogren's syndrome.Ann Rheum Dis. 2005 Mar;64(3):468-70.

24 Campisi G. HPV DNA in clinically different variants of oral leukoplakia and lichen planus. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2004 Dec;98(6):705-11.

25 Xi S etal. Gene therapy for the treatment of oral squamous cell carcinoma. J Dent Res 2003; 82: 11-16.

26 Baum JB. The impact of gene therapy on dentistry. JADA 2002; 133: 35-44.

27 Wang J et al. Predominant cell-mediated immunity in the oral mucosa: gene gun-based vaccination against infectious diseases. J Dermatol Sci. 2003 May;31(3):203-10.

28 Slavkin HC. And the next 50 years. The future of DNA technology in oral medicine. JPHD 1996; 56: 278-85.

29. webmaster@craniofacial.org.uk30. http://uhavax.hartford.edu/bugl/hiv.htm#types31.http://www.medschool.lsuhsc.edu/genetics_center/louisiana/

article_oralcavity2_p.htm32 . webmaster@craniofacial.org.uk33. http://uhavax.hartford.edu/bug/hiv.htm#types34 .www.cancerquest.org/index.cfm?35 .Faiez N. Genetics. DCNA. 1975. 1-150.36. Wise GE. Cell and molecular biology of tooth eruption. In:

Davidowitch Z. Biologic mechanisms of tooth eruption. Ed. Harvard society. Boston. 1998. 1-7.

128

37. Griffiths, Anthony J. F.; Miller, Jeffrey H.; Suzuki, David T.; Lewontin, Richard C.; Gelbart, William M., eds. (2000). "Genetics and the Organism: Introduction". An Introduction to Genetic Analysis (7th ed.). New York: W. H. Freeman.

38. Book : Biotechnology & Genetic engineering (Kathy wilson peacock) 2010,Edi:1 : Page No. 4 (Chapter 1)

39. D. L. Hartl and V. Orel (1992). "What Did Gregor Mendel Think He Discovered?".Genetics 131 (2): 245–25

40. Zambryski, P.; Joos, H.; Genetello, C.; Leemans, J.; Montagu, M. V.; Schell, J. (1983). "Ti plasmid vector for the introduction of DNA into plant cells without alteration of their normal regeneration capacity". The EMBO Journal 2 (12): 2143–2150.