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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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Genetics, Problems and Approaches. 3rd ed. New York: Springer; 1997. p. 1-22.
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11 Anderson M. Risk Assessment and Epidemiology of Dental Caries: Review of Literature. Pediatr Dent 2002; 24(5): 377-385.
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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.
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