Dna Fingerprinting : Dna Fingerprinting RANI ASHOK
LECTURER (SS) IN ZOOLOGY
LADY DOAK COLLEGE, MADURAI - 2 Slide 2: Era of DNA Technology: Information through DNA Slide 3: “(DNA technology) – The most awesome and powerful tool acquired by man since the splitting of atoms”
- The Time Magazine (USA) Slide 4: “The molecule is so beautiful. Its glory was reflected on Francis and me.” - James Watson on DNA The “blueprints” (genetic information) for making proteins is stored within our DNA. It is the job of DNA to control the order in which these 20 different amino acids are put together.
The DNA of every human being on the planet is 99.9% the same. It is the 0.1% that makes all the difference!
Any type of organism can be identified by examination of DNA sequences which is unique to that species. The molecule of life: DNA Definition : Definition Technology using tandem repeats of individuals to identify individuals is known as DNA fingerprinting Technology Transition : Technology Transition “DNA Fingerprinting” – Dr. Alec Jeffreys – 1985
“DNA Profiling” – FBI (RFLP) – 1988
PCR DQalpha & Polymarker– 1990
PCR STRs – 1993
Mitochondrial DNA - 1996
Multi-plex STRs – 1997
Chips YOUR DNA: Your Ultimate Genetic Bar Code : YOUR DNA: Your Ultimate Genetic Bar Code DNA Fingerprinting is a method where:
a person’s genetic traits, genes, are used to make specific strings of DNA letters that are cut into patterns of shorter strings separated by length these banding patterns can identify a unique human being! YOUR DNA Banding Pattern Will Identify YOU! Image of a DNA fingerprint : Sequence Repeats in the Human Genome Variable Number of Tandem Repeats (VNTR):
repeats of 9 to 80 base pairs (bp), total length is 500 to 23,000 bp, very specific due to length and repeats, testing is expensive and time-consuming, degrade in older DNA samples due to random breaking of DNA strands
Amplified Fragment Length Polymorphisms (AmpFLP):
repeats of 8 to 16 bp, total length 100 to 1300 bp, shorter and less susceptible to degradation, first loci to be used in forensic analysis CONTD … : CONTD … Short Tandem Repeats
repeats of 2 to 7 bases, total length 100 to 400 bp, shorter yet thereby less susceptible to breakage, these loci are the current standard in forensic laboratory analysis, ideal size for PCR amplification
Single Nucleotide Polymorphisms (SNP):
a single base change as a result of mutation, not commonly useful to forensic investigators, can be potentially used to distinguish identical twins Applications of DNA Fingerprinting : Applications of DNA Fingerprinting DNA Fingerprinting and Forensics : DNA Fingerprinting and Forensics Forensic science can be defined as the intersection of law and science
First photography-then fingerprint- then, in 1985, DNA Fingerprinting Slide 16: Criminal Identification & Forensics
DNA fingerprints can be used as biological evidence
Strands of DNA can be found on hair, blood or semen. Slide 17: DNA isolated from those evidence can be compared through VNTR patterns.
Useful in solving crimes like murder and rape.
Example: The sex scandal of President Clinton with Monica Lewinsky
Double murders of O.J. Simpson in 1995. Maybe You Shouldn’t Believe Your Eyes! DNA Fingerprinting Reveals The Truth! : Maybe You Shouldn’t Believe Your Eyes! DNA Fingerprinting Reveals The Truth! DNA Fingerprinting has exonerated people who
were falsely convicted.
What is the most common error leading to wrongful conviction?
Identification! Awesome Power: The Innocence Project: DNA MIGHT SET YOU FREE! : Awesome Power: The Innocence Project: DNA MIGHT SET YOU FREE! Slide 20: CODIS – Combined DNA Index System National software developed by the FBI
Distributed to local, state, and national crime labs
All 50 states mandate inclusion of DNA fingerprint (if available) from violent and sexually motivated crimes
Mostly a database of STR regions
Thousands of matches have led to the capture of criminals that otherwise would not have been caught
This has led numerous people to suggest a national DNA database that would include only polymorphism information… DNA PROFILING BOARD : Recommend privacy protection statutes relating to access to, or use of stored DNA samples or DNA analyses
Recommend on the appropriate use and confidentiality of DNA information, and the timely removal of expunged or inaccurate DNA information
Lay down standards and procedures for establishment and functioning of DNA Data Banks, manpower and infrastructure and other related issues
Define, implement and arbitrate on all Ethical and Human Rights issues emanating out of DNA profiling in consonance with International guidelines laid by the UN/UNESCO DNA PROFILING BOARD Slide 22: - shall have following indices for various categories of data (DNA identification records):
(i) a crime-scene index;
(ii) a suspects’ index;
(iii) an offenders index;
(iv) a missing persons’ index;
(v) an unknown deceased persons’ index; and
(vi) a volunteers’ index DNA databank No person who receives the DNA profile for entry in the DNA data bank shall use it or allow it to be used for purposes other than for the administration of this Act.
Criteria specified for removal of information (eg., when a conviction has been set aside on appeal) or retention of DNA Profiles
Post-conviction DNA testing for establishment of innocence Slide 23: DNA Databank : comparisons with laws of other countries Criteria for entry of DNA profiles into databank vary from country to country eg., Belgium has no Suspects’ database, Austria limits it only for suspects of “serious offenses”, UK has it for all suspects Likewise, criteria for removal of DNA profiles from databank also vary eg., in time of retention for convicted offenders as well as for suspects; in the UK, the law allows for indefinite retention of suspects’ profiles even if the suspect is released or acquitted Slide 24: Ethical, Legal, and Social Concerns about DNA Data banking
DNA patterns may not be neutral
Fairness in the use of genetic information in the database by insurers, employers, courts, schools, adoption agencies, and the military, among others. Who should have access to personal genetic information, and how will it be used?
Privacy and confidentiality of genetic information: Who owns and controls genetic information?
Psychological impact and stigmatization due to an individual's genetic differences: How does personal genetic information affect an individual and society's perceptions of that individual? How does genomic information affect members of minority communities? Slide 25: DNA technology: Are we taking the human element out of it? ? What if your blood sample for medical check-up is used for research or other purposes without being informed?
? Genetic testing: what if it cause unnecessary stress and unwelcome changes in personal relationships
? Should genetic testing be carried out where there is no treatment available…as in albinism and dwarfism?
? What do you think about the following cases?
- genetic testing for insurance
- genetic testing for new employees
- genetic databanks for forensic use
- genetic databanks for institutionalized children
? Would it cause social biasness: what if people with ‘aggression genes’, ‘cancer genes’ or ‘mood-swing genes’ are considered the Bad Seeds! Questions regarding GENES and PRIVACY Slide 26: We need to be careful, sensitive and aware
DNA is an unchangeable information about an individual or population, therefore can be used or misused.
We should be sensitive to ethical and social outcome of the information. It should not lead to discrimination to minorities, crime prevention discrimination, forceful DNA sampling etc.
Storage of DNA and DNA test results should be highly secured
Storage of authorization, national boundaries and legal limits should be chalked out carefully
Social awareness about the issue Slide 27: We have recently advanced our knowledge of genetics to the point where we can manipulate life in a way never intended by nature.
We must proceed with the utmost caution in the application of this new found knowledge.
LUTHER BURBANK Time for legal system and science to work together Slide 28: The gene revolution is forcing judges to deal with science in a way
they never had to before
Questions about the legal relationship between an egg donor, her husband, person being cloned, a surrogate mother and the resulting Child, legal rights , privileges and immunities a cloned child could claim in a jurisdiction that bans human reproductive cloning Slide 29: Parentage tests
determine if the alleged father of a child is the biological father
The child (C) will share one band with the biological mother (M) and one band with alleged father #1 (AF1), the biological father. No bands are shared between the child and alleged father #2 (AF2), the excluded male. Slide 30: Detection of Aids Slide 31: add the blood with the man’s DNA, with RNA of HIV, together with "reverse transciptase" which turns RNA into DNA fragments into the PCR machine for amplification
put them into the gel electrophoresis
compare the band of HIV "DNA" with the bands form by the man’s blood Slide 32: Breeding Program
Breeders traditionally use the phenotype to judge the genotype of a plant or an animal
For example, homozygous dominant genotype AABB is desirable.
Difficult to distinguish homozygous or heterozygous dominance from appearance. Slide 33: DNA fingerprinting allows a precise and accurate determination of genotype
Offspring from the selective mating of superior animals are like more likely to inherit desirable characters like strong cardiopulmonary capacity and speed.
Useful in breeding race horses and hunting dogs Slide 34: Advantages of DNA Fingerprinting Slide 35: 1.Unsurpassed discriminatory potential
Complete blood group testing allows discrimiation of one person in several thousand and HLA typing one in several million
DNA typing can routinely provide exclusion probabilities on the order of one in billions Slide 36: 2.Exquisite sensitivity
DNA can be amplified
smaller sample sizes are adequate
allows rather small samples to be split and submitted for testing to more than one laboratory Slide 37: 3.Application to any body tissue
DNA testing can be conducted with any sample having nucleated cells
For example hairs, semen, urine and saliva Slide 38: 4.DNA is stable in comparison to proteins
resistant to degradation by common environmental insults
DNA is also long-lived in comparison to protein Disadvantages of DNA Fingerprinting : Disadvantages of DNA Fingerprinting Slide 40: Problems with determining probability
DNA fingerprinting is not 100% assured
VNTR are results of genetic inheritance
not distributed evenly across all populations
cannot have a stable probability of occurrence.
Due to allele frequencies in different population or ethnics groups, the probability of match can range from 1 in 20 to 1 in 2 billion. Slide 41: Occurrence of certain VNTR pattern depends on an individual’s genetic background.
Big problem in determining the VNTR patterns of heterogeneous genetic composition of interracial individuals
For example, the frequency of a specific allele may be 4% in Asians instead of 1% as it is in Northern Europeans. Slide 42: Contamiination of the sample
Shifting of bands produces wrong information. Slide 43: Thank You ...