DNA fingerprinting by sharada avadhanam

Significance of DNA
DNA is the genetic material and the carrier of genetic traits.
A part of the DNA of various individuals is the same.
But another part differs from individual to individual
except in the case of identical twins.
Pioneers:
Alec Jeffreys , in 1985 ; Lalji Singh in 1988
Showed genetic Bar Code
following simple law of heredity,
a child inherits one half of the bands from mother & rest from father.
What Is DNA?
DNA, or deoxyribonucleic acid, is the fundamental building block for an individual's entire genetic makeup.
Further, a person's DNA is the same in every cell. DNA in blood is the same as in skin cells, semen, and saliva.

DNA fingerprinting
Of unrelated individuals are different
Related individuals show a higher coefficient of similarity
Each of the bands of a child
Must match
With a band either in the father’s or mother’s DNA


The technique of DNA finger printing
fool proof method
identity
parentage.
identity
child belongs to parents ?
the identity of individual ?
bone belong to a disappeared person , murdered years ago ?
blood or semen stains, from site of murder or rape, belong to suspect, or is he innocent.
Applications:
in pedigree analysis and
establishing paternity.
In establishing family relationship for immigration authorities.
In rape cases,
a few hair roots or a small sample of blood, buccal smear, semen spits or skin tissue
sufficient to obtain genetic finger printing.
compare with suspect to confirm the rape charge beyond any doubt.

investigating rape cases
collect and analyze
the DNA of the victim's recent consensual partners to eliminate them as potential contributors of DNA suspected to be from the perpetrator.
If this is necessary, it is important to approach the victim with extreme sensitivity and provide a full explanation of why the request is being made.

Blood stains stored under favourable conditions
have been successfully analysed upto three years and seminal stains upto four years after collection.
It is possible to separate the DNA of male origin when semen is mixed with vaginal secretions.
Vaginal swab taken upto 20 hours after intercourse can be used to isolate DNA from sperm.
The identification of mutilated dead bodies
from their tissue remnants can be established with the help of DNA finger printing of close relatives.
In social security record identification.
DNA testing
In burglaries,
evidence consists of
blood found at sites of forced entry.
Saliva, skin cells,
bone, teeth, tissue,
urine, feces
Saliva
chewing gum
cigarette butts, envelopes,
drinking cups
Fingernail scrapings useful
DNA testing of urine -in illegal drug cases
In solving murder cases
blood swabs from the murder weapon used and found in the possession of the accused or
blood spots on the accused clothes
The two DNAFP should be identical.
DNA collected from a crime scene
can either link a suspect to the evidence or
eliminate a suspect
identify a victim through DNA from relatives, even when no body can be found.
when evidence from one crime scene is compared with evidence from another, those crime scenes can be linked to
the same perpetrator
locally, statewide, and across the Nation
Forensically valuable DNA
can be found on evidence that is decades old.
several factors can affect the DNA left at a crime scene,
including environmental factors (e.g., heat, sunlight, moisture, bacteria, and fungus).
not all DNA evidence will result in a usable DNA profile.
Where can DNA evidence be found
One murder was solved when the suspect's DNA, taken from saliva in a dental impression mold, matched the DNA swabbed from a bite mark on the victim.
A masked rapist was convicted of forced oral copulation when his victim's DNA matched DNA swabbed from the suspect's penis 6 hours after the offense.
Numerous cases have been solved by DNA analysis of saliva on cigarette butts, postage stamps, and the area around the mouth opening on masks.
DNA analysis of a single hair (with root) found deep in the victim's throat provided a critical piece of evidence used in a capital murder conviction.
Contamination
DNA evidence can be contaminated when
DNA from another source gets mixed with DNA relevant to the case.
someone sneezes or coughs over the evidence or
Touches his/her mouth, nose, or other part of the face and then
touches the area that may contain the DNA to be tested.
To avoid contamination - precautions:
Wear gloves. Change them often.
Use disposable instruments or clean them thoroughly before and after handling each sample.
Avoid touching the area where you believe DNA may exist.
Avoid talking, sneezing, and coughing over evidence.
Avoid touching your face, nose, and mouth when collecting and packaging evidence.
Air-dry evidence thoroughly before packaging.
Put evidence into new paper bags or envelopes, not into plastic bags.
Do not use staples.
Transportation and storage
keep the evidence dry and at room temperature.
Once the evidence has been secured in paper bags or envelopes,
it should be sealed, labeled, and transported in a way that ensures
proper identification of where it was found and proper chain of custody.
Never place evidence that may contain DNA in plastic bags because plastic bags will retain damaging moisture.
Direct sunlight and warmer conditions also may be harmful to DNA,
so avoid keeping evidence in places that may get hot, such as a room or police car without air conditioning.
For storage over long-term , contact FSL
Elimination samples
elimination samples to determine whether the evidence comes from the suspect or from someone else.
An officer must think ahead to the time of trial and possible defenses while still at the crime scene.
For example, in the case of a residential burglary where the suspect may have drunk a glass of water at the crime scene,
an officer should identify appropriate people, such as household members, for future elimination sample testing.
Elimination samples
These samples may be needed for comparison with the saliva found on the glass to determine whether the saliva is valuable evidence.
In homicide cases, be sure to collect the victim's DNA from the medical examiner at the autopsy, even if the body is badly decomposed.
This may serve to identify an unknown victim or distinguish between the victim's DNA and other DNA found at the crime scene.

COmbined Dna Index System--CODIS
an electronic database of DNA profiles that can identify suspects, is similar to the AFIS (Automated Fingerprint Identification System) database.
States to implement a DNA index of individuals convicted of rape, murder, and child abuse.
Upon conviction and sample analysis, perpetrators' DNA profiles are entered into the DNA database.
Just as fingerprints , DNA profiles from a crime scene can be entered into CODIS.
Therefore, police have the ability to identify possible suspects when no prior suspect existed.



Blood Collection packing procedure
Furniture immovable items:Murder assault burglary dacoity
Scrap using knife into clean dry polythene bag
Swab with sterile gauze wet with saline.
each separately.
Send Unused gauze as control
Photograph / sketch the stain in situ

Liquid blood in paternity maternity disputes
10ml of blood sample to be collected in case of adults.2-5ml in case of children. In sterile vial. Pinch of EDTA to preserve. Store and transport in thermos containing ice.
Semen in rape cases
Clothes to air dried and packed in dry poly cover and seal. Don’t fold crush the stain.
Swabs to be air dried and put in glass vial and seal
From immovable articles- collect with gauze in saline- air dry pack in dry poly bag and seal
Vaginal swabs be air dried and packed in vial and seal.
Saliva in murder assault rape
Stained material to be collected using gauze cloth wet with saline. Air dry and pack in poly bag and seal.
Cigarette buds, beedi buds – dry and pack in poly cover and seal
Tissues in murder, accident, unidentified bodies, mass disasters
Muscle tissue at crime scene be collected in glass bottle, add 20% dimethyl sulphoxide with sodium chloride
In decomposed dead body- muscle tissue close to the femur or humerus should be dissected.100 gms to be sent in clean glass bottle. add 20% dimethyl sulphoxide with sodium chloride

Bones in murder accidents unidentified bodies mass disasters
Whole bones femur, humerus, rib bones to be collected and packed in dry poly bags and seal. Or keep in aluminium foil and freeze. Seal.
Teeth with jaws to be packed in dry poly cover and seal.

Hair in murder accident rape
Hair with roots to be dried and packed in dry poly cover and seal.
Fingernail clippings in murder and rape to be sent in clean dry injection bottle and seal.
Viscera: intestine spleen heart - avoid liver
in murder accident unidentified bodies and mass disasters
To be preserved in clean dry glass bottle. Add 20% dimethyl sulphoxide with sodium chloride and seal.

Poly covers
Self locking poly covers preferred or they be hot sealed.
Label all samples clearly
Use clean gloves to handle the garments or any other biological specimens as you may shed your own cells from the skin and contaminate the samples.




Declaration form
Declaration of the person from whom the sample is collected for DNA finger printing:
I, ………………………………………………., hereby certify that the blood given to FSL for DNA fingerprints, is mine and I did not receive a blood transfusion within last three months.
(Signature of donor or guardian)
Certificate:
Certified that the ………………………………., was collected in the presence of the following witnesses:
Name & Signature
Name & Signature
[ for office use ] FSL file no……………………………………


CASE STUDIES:


DNA tests help girl reunite with parents:
With regard to the real parents of 13-year-od girl chandrakala, who was traced eight years after she had gone missing, DNA tests confirm her real parents as parvathaluand yellamma of venkatampalli in Mahaboobnagar district.
Parvathalu with five-year old chandrakala and yellamma came to the city for a function,
and on the same day chndrakala was found missing and a complaint was duly lodged with the police.
Eight years later, they chanced to see chandrakala with a couple, prameela and yadagiri as her parents.
When parvathalu approached the police, chandrakala’s blood samples land those of the two couples were collected for DNA tests.
The report confirmed that chandrakala was born to parvathaluand yellamma.

a false allegation of swapping of male child from the hospital
One Mr.Rajaiah lodged complaint with the police stating that his wife Smt. Rajeswari delivered a male child in the hospital at Godavaridhani, and that the hospital authorities showed a female child; and that his newly born son was swapped.
The couple and the child were sent to FSL for DNA tests to determine the biological parenthood.
The DNA tests proved that they are the biological parents of the female child only, there by proving that his allegation against hospital authorities was false one.
In a case from Nalgonda, the victim a pregnant lady committed suicide,
because the accused disowned her pregnancy and hence did not marry her.
During post-mortem, the tissue of the foetus was preserved and sent for DNA tests.
The blood sample of the accused was collected and the DNA was matched with DNA sample from the tissue of foetus.
It is proved that he was the biological father.

In a case of murder wherein husband killed his wife and falsely implicated three other persons.
He caused injuries to himself and created a scene as if he was injured during the struggle. All the exhibits were sent for DNA examination .
The blood scrapings from the victims nails, the knife with which the husband caused injuries to himself and the blood sample of the accused, all samples were showing the same DNA pattern.

The murder of Mr.B.R.Seth, CE, S.C.R and his family.
Mr.B.R.Seth, his wife, his daughter and his son all were murdered and burnt in a car, by their servant. Their identity was also lost.
The muscle tissues, blood stains found at their house, blood stains recovered from the house of accused, all were sent to FSL for their identification.
The live daughter of Mr.Seth and parents of Mrs.Seth and one accused person all were directed to FSL for giving their blood samples for comparison.
The deceased family members were identified, the involvement ofl the accused person in the incident was established through DNA tests.

In another case at Nalgonda, a person was burnt alive in a car.
The car and dead body were burnt. The dead body was suspected to be of either one Mr.Guntur Ramarao or Mr. Rajaki Ramulu Naik.
The viscera samples of the deceased were recovered and sent to FSL for identification. Two brothers of Mr. Guntur Rama Rao and parents of Mr.Janaki Ramulu Naik were directed to FSL for giving their blood samples to establish the identity of the deceased.
The DNA analysis conclusively proved that the deceased person was Mr.Janaki Ramulu Naik. The other person Mr.Guntur Ramarao,m a business man, killed Mr. Nayak, burnt him along with the car to rule out the identity of the deceased, and absconded for a longtime, giving an image that he himself was the victim.
All this was done for monetary benefit. But finally DNA tests proved the identity of the actual deceased.

In a case, vemireddy madhusudanreddy committed rape
on smt. Sunita,w/o venkat reddy and killed her due to sexual jealousy by beating her and making her consume poison forcibly.
He was brought to FSL for collection of his blood sample for DNA tests.
The DNA tests proved that the DNA in seminal stains on the petticoat of the victim matched with DNA profile of the accused’s blood and proved his involvement in the said act.

BRITISH EMBASSY CASE- IDENTITY OF MISSING BRITISH NATIONALS:
During Gujarat riots four persons while traveling in a car were attacked and burnt by a mob.
One person died, another escaped while the other two were missing.
For the identity of the missing persons the burnt bones found at the scene were sent for DNA examination along with the suspected deceased mothers blood samples.
From the burnt bones only one bone yielded DNA and helped in identifying one of the deceased persons.

REUNION OF MISSING CHILD WITH ORIGINAL PARENTS:
In a case of paternity a boy from Muslim family staying at Krishna district was sent to Hyderabad to stay under the care of his uncle.
Due to the ill-treatment by his uncle the child left home. An auto-driver found the child and admitted him in a hostel at Nalgonda.
Another Hindu couple residing at Hyderabad, who also had lost their child brought him home from the hostel and claimed him to be their’s.
Both the couples claiming for the child filed la case and it was referred to FSL for identifying the parents of the child.
The DNA tests revealed that the child belonged to the muslim couple.
Thus the DNA tests reunited the child with the original parents.

CHILD SWAPPING: DNA TESTS PROVED ALLEGATIONS WRONG:
A couple K.Padma and Sailu; and their family members alleged that Padma’s baby boy was swapped for a girl within hours of delivery at the Koti Government Maternity Hospital.
The baby girl and the couple were sent to APFSL for DNA tests.
The tests proved that the couple’s contention was wrong and that the female child was theirs.

GANG RAPE CASE:
In a case from Mahaboobnagar district a woman was gang raped by two persons.
The seminal stains on the garments of the victim and blood samples of both suspects were subjected to DNA fingerprinting.
The DNA fingerprinting profile of both the persons and DNA of seminal stains tallied clearly linking both the subjects to the crime.