Forensic significance of DNA profiling... Forensic genetics biological specialization

1. FORENSIC SIGNIFICANCE OF
DNA - PROFILING
Submitted to – Dr.Sapna sharma mam
Submitted by – Shabnam
Roll no.- 1303

2. Index
1) Introduction
2) Disputed paternity case
3) Child swapping
4) Veterinary cases
5) Plant testing
6) Wildlife cases
7) Missing person identity.

3. Introduction
• DNA profiling is a forensic technique which help to solve
the cases in different aspects.
• The application of DNA profiling in disputed paternity
cases , child swapping cases , missing person
identification cases, agricultural cases ,plant testing etc.
• DNA profiling plays an important role in the field of
forensics science to solve the various criminal cases.

4. Disputed paternity cases
• Paternity disputes cases arise when a father claims that
he is not he biological father of that child , however
mother claims that the man is the biological father of her
child.
• These techniques of DNA – Typing help to solve such
cases:
1. Variable number of tandem repeats (VNTRs)
2. Polymerase chain reaction (PCR)
3. Short tandem repeats (STRs)
4. Restriction fregmant length polymorphism (RFLP)

5. In case of alleged father

6. VNTRs
• VNTRs are the type of minisatellite in which the size of repeat
sequence is generally 10 to 100 bp.
• Minisatellites are the type of DNA tandem repeats sequence that
is sequence repeat one after another without other nucleotide in
between them. This is about 10 to 100 nucleotides.
• The sequence of minisatellite are larger than the microsatellite (2
to 6 nucleotide).
• VNTRs can vary in numbers of repeats from individual to
individual.

7. Conts.
• VNTRs profiling utilizes RFLP techniques which is the first
historical method used in DNA testing.
• It utilize the “restriction endonucleases” that recognize
and cleave the specific site along the DNA sequence
which is reproducible set of restriction fragments of
various length.
• Resultant different length of fragments produced will
differ when the DNA is digested with restriction
enzyme.This different pattern can be used to differentiate
species from one another.

9. Y - STRs
• It’s a male specific technique and shows the patrilineage
phenomenon.
• Hence, very useful in forensic DNA testing .And for
investigation in sexual assault cases involving male
suspects.
• The evidence gathered in such cases usually it consists of
a mixture of high level of female DNA and low level of
male DNA.In case of sexual assault, Y-STRs system is
useful for determinig the number of unrelated male
perpetrator in sexual assault cases.
• But YSTRs cannot distinguish between same patrilineage
individuals.

10. Inheritance of Y-STR

11. Mitochondrial-DNA analysis
• It’s a female specific type of testing, mt.DNA is situated in
cellular organalle within eukaryotic cell.Mt.DNA is circular
in shape.
• May be useful in finding family relation of unknown person
such as in disaster case Tzar Nicholas II , in solving
historic puzzules and to link families.
• Having very useful in recovery of DNA environmentally
demaged DNA is sometimes even possible with mt.DNA.
• But mt.DNA is cannot distinguished between same
metrileneage or all same mothers.

12. Inheritance of mt.DNA

13. STRs
• A short tandem repeats is a region of genomic DNA
containing an array of short repeating sequences.
• STRs technique is PCR based,applicable in degraded
DNA,shows rapid results,show result in even small
quantity DNA.
• Two major abandant used STRs kits are Promega
coorporation and applied biosystem type kits which is
used by forensic community.Manufacturer of STR kits
provide allelic ladders that may be used for accurate
genotyping kits from Promega coorporation and applied
biosystems for comparable STR markers often contain
different alleles in their allelic ladders.

14. STRs result interpretation

15. Child swapping
• Being parent and child caring is a wonderful experieance
of everyone life.
• A baby swapping happens all around the world and a
nowdays it is quite common newspapers and other media
plateforms.
• Many time suspected from family members or hospitals
staff.But now it can be detected by conducted a simple
DNA test of intended infant with alleged
mother.Mitochondrial DNA is compared with infant.
• There was a case happens in May 2015 in UK.
Mr.Richard Cusworth and his wife Salvadoran case of
child swapped.Maternity test prove the son Moses was
swapped with another baby.

16. Veterinary cases
• The main applications od DNA testing in domestic animals
for diagnosis of genetic disease and for sexing animals.
• In horses as well as other farm animals , selective
breeding requires exact lineage records.
• The veterinary Genetics laboratory Forensic unit at
university California , Devis is first accrediated to
animals DNA profiling.
• The three main type of cases:
a) Where animal is victim.
b) Where animal is perpetrator.
c) Where animal is witness.

17. Conts.
• Locard exchange principle maintain that every contact leaves
traces,exchange can bear mute witness to each and every crimes.
• If you own a cat or dog, you know that their fur accomplished you
throughout the day, from your home to your car ,from your car to
your office.That fur (or saliva ,urine ,blood) can become crucial
evidence in forensic investigations.Veterinary DNA profiling had
been used in every state of US.

18. Plant testing
• Crimes often occurred in localized area containing the
unique combination o botanical growth.If these
plants,algae,grasses are sufficiently rare, then recovery of
trace evidence from the clothing of a victim or personal
property of a suspects may helpful in making that can link
them to crime scene.
• In plant testing, two primary areas are currently being
investigated. The first linking of plant material to suspect
to make association link with crime was committed.
• The second linking marijuana to aid in forensic
investigation.

19. Wildlife cases
• Often animals are tortured or killed by someone trying to
controlled another person in domestic violence situations.
• Animal evidence can help to solve a wide range of cases
from animal cruelty or theft,to the animal attack on
humans or other animals.
• Pet hair is commonly collected item of non human
biological evidence and not suited to individual (neclear)
DNA profiling.
• However,unlike humans – dogs and cats hairs without
root can yield enough DNA for individual DNA profiling.
• If the mt.DNA found in cytoplasm of all the anima cells can
be tested to include or exclude contributor.

20. Non – human DNA identification
• When animals involve in an attack on a person.DNA typing
may be used to identify the animal perpetrator.
• If the victim deceased then DNA evidence may be the only
witness that an animal in custody committed the
crime.Animal DNA testing exonerate the innocent animals.

21. Missing person identity
• Forensic DNA typing provides data from variety of
materials and individuals and applied to many important
issues that confront the society.
• DNA database house DNA profiles from convicted felons,
forensic evidences, human remains and direct and family
reference samples of missing persons.
• In forensic investigation of human reamains comes under
two objectives
1. To recover and examine the remains for criminal
investigations including cause and manner of death.
2. To identify if possible return to them to family of dead
person.

22. Conts.
• This process id done by retrive the DNA and compare
either from relatives of missing person ( hair, saliva, stains
etc.).
• A shorter portion of DNA part, then STRs technique is
useful in that case.
• Mitochondrial DNA recover easily from human remains.
• Sex chromosomes is possible to analyze a penal STRs
that are located on Y-chromosome in order to match the
remains with male relatives.
• It is more useful when close relative are not available for
comparison because of petrilineage.

23. SNPs
• It refers to as single base difference in the sequence of
DNA at particular point.SNPs are abundant in human
genome, being used as linkage studies to track disease.
Advantage : a) It give sufficient information to identify the
human can be selected or identified.
b) SNPs are smaller than STRs hence more useful than
STRs in identification od degraded sample.
c) SNPs show less mutation rate over STRs.

24. Thankyou