Identification. Personal identification methods:

Identification

Personal identification methods:

I. Anthropometry:This method depends on the accurate measurement of certain parts of the adult body, e.g. head, left arm, etc. This method is liable to errors as a result of different measures taken by different persons.

II. Portrait Parlé: includes the following:1. Description of the features.2. Color of hair on the scalp, beard, moustache and other parts of the body.3. Color of the iris of the eye.4. Description of any body peculiarities.5. Description of any characteristic marks on the body, e.g. scars or tattoo marks.5. Photographs: side view and face view.

Photography in portrait parlé:Side view and face view

N.B. Both anthropometry and portrait parlé can not be relied

upon for sure in all cases of personal identification.

FINGERPRINTS CAN BE CLASSIFIED INTO 4 MAIN GROUPS:

1. ARCHES.2. LOOPS.3. WHORLS.4. COMPOSITE.

III. Dactylography (fingerprints):

Classification of Fingerprints

The prints of each group can be differentiated from each other by their detailed structures, e.g. bifurcations or unions of the ridges forming the print.

Fingerprints are specific for each person, i.e. there are no 2 persons with identical fingerprints, even in

identical twins.

Detailed Structure of a Fingerprint

The pattern of the print is present before birth (from the fourth month of pregnancy, approximately), and remains constant during the whole life of the person.

The fingerprints will not disappear except after operation or after the application of caustics to them.

In such cases, there will be a scar which is still a point of identification.

After death and peeling of the superficial layers of the skin as a result of putrefaction, the deeper skin layers will still carry the characteristics of the print.

Personal identification by dactylography is useful only

when there is a previous records for these prints, to be used for

comparison.

Automated Comparing of Fingerprints

To take fingerprints of a person, his fingerprints are moistened with

printer’s ink, then the impression of each of his 10 fingers is taken and

preserved on a clean paper.

Poroscopy: is the study of the sweat glands pores on the print,

after enlargement of a photograph for that print. The number and distribution of these pores is a

point of identification.

Poroscopy

IV. Bone

1. Determination of Sex• Pelvis is the best bones (differences due to

adaptations to childbirth)

females have wider subpubic angle

females have a sciatic notch > 90°

females have a broad pelvic inlet

1. 1.

1.

2. 2.

2.

3.3.

3.

1. Determination of Sex• Pelvis best (another view)

females have wider subpubic angle

females have a broad, shovel-like ilium

females have a flexible pubic symphysis

1. 1.

2. 2.3.

1.2.

3.

1. Determination of Sex: Cranium

• Crests and ridges more pronounced in males (A, B, C)

• Chin significantly more square in males (E)

• Mastoid process wide and robust in males

• Forehead slopes more in males (F)

Determination of Age

• The long bones are those that grow primarily by elongation at an epiphysis at one end of the growing bone. The long bones include the femurs, tibias, and fibulas of the legs, the humeri, radii, and ulnas of the arms, and the phalanges of the fingers and toes.

• As a child grows the epiphyses become calcified (turn to hard bone)

Epiphyseal Fusion • The figures below are of the Epiphyses of the femur or thigh bone (the

ball end of the joint, joined by a layer of cartilage).• The lines in the illustrated Image 1 show the lines or layers of cartilage

between the bone and the epiphyses. The lines are very clear on the bone when a person, either male or female is not out of puberty.

• In Image 2, you see no visible lines. This person is out of puberty. The epiphyses have fully joined when a person reaches adulthood, closing off the ability to grow taller or in the case of the arms, to grow longer.

Figure 1. Figure 2.

Cartilage is darker on xray than solid bone. Epiphyses aren’t fused yet.

No cartilage visible. Epiphyses are fused.

•Union of epiphysis:•Trochlea fuses with capitulum (humerus) : 14 years•Illeum, ischium and pubis unite with acetabulum: 15 years•Troholea and captulum with the shaft of humerus: 15 years•Lateral epicondyle of humerus: 16 years•Upper end of ulna: 16 years•Lesser trochanter of femur: 16 years•Medial epicondyle of humerus : 17 years•Upper end of radius: 17 years•Greater trochanter of femur: 17 years•Epiphysis of metacarpals and phalanges: 18 years

•Head of the femur: 18 years•Lower end of tibia: 18 years•Head of the humerus: 20 years•Distal end of radius: 20 years•Distal end of ulna: 20 years•Upper end of tibia: 21 years•Lower end of femur: 21 years•Epiphysis of ischial tuberosity: 21 years•Epiphysis of iliac crest: 20- 25 years•Basi-occiput with basi-sphenoid: 20- 25 years

Fusion of suturs of the skull:

•Sagital suture: 25- 30 years

•Coronal suture: 40 years

•Lambdoid suture: 50 years

V. Teeth

Age of 6 – 24 months is identified by milk dentition as follow:

Central incisors : 6 monthsLateral incisors: 9 monthsFirst milk molar: 12 monthsCanine: 18 monthsSecond milk molar: 24 months

Age of 6 – 12 years is identified by permanent dentition as follow:First permanent molar: 6 yearsCentral incisors: 7 yearsLateral incisors: 8 yearsFirst permanent premolar: 9 yearsSecond permanent premolar: 10 yearsCanine: 11 yearsSecond permanent molar: 12 yearsThird permanent molar : 17 – 25

VI. BLOOD

Question 1: Is the stain blood or not?

Preliminary tests: 1. They depend on the presence of the oxidase enzyme in blood. 2. The oxidase enzyme helps oxidation of the oxidizable substances in these tests such as (Guiacum, Benzidine and Kasle-Meyer or Phenolphthalein test).3. The oxidation occurs in the presence of oxygen source such as H2O2.4. The oxidation is identified by the change of color of reagents used.5. They can be carried out on a filter paper.

Guiacum test: ½ cc of stain extract + ½ cc Guiacum reagent + ½ cc H2O2 → green color. It is sensitive up to 1/5.000 of blood

dilutions.

Benzidine test: ½ cc of stain extract + ½ cc benzidine reagent +

½ cc H2O2 → blue color. It is sensitive up to 1/300.000 of blood

dilutions.

Kastle-Meyer test: ½ cc of stain extract + ½ cc Kastle-Meyer

reagent + ½ cc H2O2 → pink color. It is sensitive up to 1/5.000.000 of

blood dilutions.

Conclusions: If preliminary tests are negative so the stain is not blood.

However, if the preliminary tests are positive so the stain may be blood

or some stain else. So we proceed to the confirmatory tests.

Confirmatory tests: Michrochemical, Microscopic,Spectroscopic tests.

Microchemical tests: Teichman test and Takayama test.

Teichman test (Haemin crystal test): It is done on a slide. Small

fragments of the stain + a few drops of Teichman reagent, then cover and heat gently, then leave slide to cool down. After that examine the slide under low power microscope if +ve test gives: Small brown rhombic

crystals of haemin.

Takayama test (Haemochromogen crystal test):

It is done on a slide as well. Small fragments of the stain + a few drops of Takayama reagent, then cover and heat gently, then leave slide to cool down. After that examine the slide under low power microscope if +ve

test gives: Pink needle-shaped crystals of haemochromogen.

Microscopic test: under microscope, blood cells can be seen, especially RBCs.

Advantages of the spectroscopic test: 1. Simple and easy.2. Applied on a very little amount of blood stain.3. Does not interfere with the subsequent chemical tests.4. It helps in the detection of certain toxins such as cyanide, carbon monoxide, Hydrogen sulfide.5. In these tests we obtain the characteristic absorption bands by examination through spectroscope, so, we can see and detect absorption bands.

Spectroscope

1. Oxy Hb: 2 absorption bands between D and E lines of the spectrum.2. Reduced Hb: prepared by addition of oxy Hb to reducing reagents such as yellow ammonium sulfide or sodium hydrosulphide. Reduced Hb gives one broad band between D and E lines.

3. Carboxy Hb: prepared by passing CO gas on oxy Hb. Carboxy Hb gives 2 bands of oxy Hb (Bet D and E lines) but they are shifted to the right.4. Met Hb: Gives 2 bands between D and E lines and a third band between C and D lines.5. Haemochromogen: Gives one band between D and E lines, in addition to another band to the right of E line.

N.B. Haemochromogen can be prepared by a few drops of

takayama reagent + Oxy Hb.

Question 2: Is it blood of human or animal? Microscopic and precipitin

tests:

Microscopic test: applied to fresh blood only:1. Human RBCs :- Rounded and biconcave- Non nucleated- Form a rouleaux- Average diameter is 7 microns.2. Camel’s RBCs:ovel and non-nucleated3. Non-mammalian RBCs e.g. frog: Oval, large and nucleated.

Precipitin test: It depends on an antigen-antibody reaction, when positive results in precipitation.

Question 3: Does blood belong to a certain person?

HUMAN BLOOD CAN BE DIVIDED INTO 4 MAIN

GROUPS: A, B, AB, AND O.

ABO Blood grouping:

ABO Blood Grouping Blood Group Agglutinogen on

the surface of the RBCs

Agglutinin in the person’s serum

A A Beta

B B Alpha

AB AB---------------------

O---------------------

Alpha, Beta

Grouping of fresh blood: 1. A citrated blood sample is diluted with saline. 2. One drop of this diluted blood is put near the end of a clean glass slide. 3. Another drop is put neat the other end of the slide.

Steps of blood grouping: 1. Add one drop of anti-A serum to the first drop on the slide.2. Add one drop of anti-B serum to the second drop on the slide.3. Mix and allow to stand for a few minutes.4. Examine for agglutination, both by naked eye, and by the low power of microscope.

Results of Blood Grouping Test

Diluted blood + anti-A serum

Diluted blood + anti-B serum

Individual’s blood group

Agglutination No agglutination Blood group A

No agglutination Agglutination Blood group B

Agglutination Agglutination Blood group AB

No agglutination No agglutination Blood group O

Blood Grouping Test Result

VII :Identification of semen

Physical characters: fresh semen is stick with a characteristic odor,

while old semen is starchy, yellowish and fluoresces when

exposed to ultra-violet light.

Microchemical tests:

1- Florence test

• Florence test (for detection of choline): on clean glass slide, one drop of stain soaking + one drop of Florence iodine reagent: in positive cases, evanescent large brown rhombic crystals, consisting from choline di-iodide.

Large brown rhombic crystals of positive Florence test for semin.

2- Barberio’s test

• Barberio’s test (for detection of spermine): on clean glass slide, one drop of stain soaking + one drop of barberio’s reagent: in positive cases, yellow needle-shaped crystals.

Yellow needle-shaped crystals are seen in positive Barberio’s test for semin.

3- Acid phosphatase test.

4- Prostatic –specific antigen test (p30).

Microscopical examination of seminal stains for presence of spermatozoa.

Microscopic detection of one complete spermatozoon is necessary to conclude the presence of semen.

Microscopical examination of seminal stains for the presence of spermatozoa.

VIII. Deoxyribo-Nucleic Acid (DNA)

DNA IS THE GENETIC MATERIAL WHICH CARRIES THE GENETIC INFORMATION RELATED TO THE PERSON.

IT EXISTS IN ALL BODY CELLS EXCEPT RBCS AS THEY ARE NON-NUCLEATED.

DNA Collection & Comparison:

• DNA is collected at crime scenes in a variety of ways using tools such as:

• Smear slides, scalpels, tweezers, scissors, sterile cloth squares, UV light, luminol and/or blood collection kits (for sample collection of suspects or living victims)

Saliva, blood, hair strands, skin, finger or toe nails, and/or a tooth with root

material.

**Note: There must be cells withnuclei present before nDNAcan be obtained.**

How is blood collected?

1. Blood on Clothing?Investigators submit whole pieces of clothing or they may use a sterile cloth square and a small amount of distilled water.

2. Dried blood on furniture?Investigators send the whole object to the lab.3. Dried blood on a wall, tub or some other object too big or difficult to move to the lab?4. Investigators scrape the blood sample into a sterile container for further analysis.

Types of DNA in the mammalian cell: nuclear and mitochondrial.

Two DNA Types in a Human Cell

Nucleus

Mitochondria

Evidentiary DNA Extraction

Evidentiary PCR Prep

• Physically separated Thermal Cycling Room for Evidentiary Samples

Applications of Nuclear DNA in Human Identification

• Sexual assault cases and other violent crimes (forensics)

• Exoneration of convicted persons (innocence projects)

• Identify serial crimes (DNA databasing)• Identify biological parents (paternity)• Identify other biological relationships (sibship)• Identify human remains (missing persons)• Infidelity testing (semen screening)

Applications of Mitochondrial DNA in Human Identification

• Maternal relationships• Forensics• Missing persons investigations• Identification of victims of mass disasters• Military actions and repatriation

Nuclear Vs. Mitochondrial DNACharacteristics Nuclear DNA

(nDNA)Mitochondrial DNA

(mtDNA)

Location within the Cell

In Nucleus In Cytoplasm

DNA Structure Linear Double helix“Twisted Ladder”

Exactly same as nDNA but circular like “twisted rubber band”

DNA Length More than 3 billion bases

Only 16,569 bases

DNA Copy Number

Two copies of each segment called a locus (plural-loci)

A few hundreds to thousands copies

مع الله بحمد المحاضرة تمتبالتوفيق تمنياتىالفضالى/ ناجى د