identification

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IDENTIFICATION

• By Dr Magde Boukhatwa
• 14-11-2018

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• Definition
• It is the recognition of an unknown person
  (living, dead or body remains) through certain
  features and characters which differentiate him
  from all others.

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• Classification
• Complete .
  
• Partial.

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• Complete identification means the absolute
  fixation of the individuality of a person.

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• Partial identification means ascertainment of
  only some facts (sex, age, race, stature) about
  the identity while others remain still unknown.

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Types

• 1- Legal identification
• It is complete description of an unknown dead
  body in order to know the identity of this person
  later on.
• It is required in
• a)Cases of fire, explosion, travel accidents.
• b)Unknown dead body found on the road, in the
  fields, railway compartment or in water.
• c)In cases of decomposed bodies, mutilated bodies
  or in skeletal remains.

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• 2- Personal or civil identification
• It is recognition of a dead body or living
  person by his relatives, friends or witness, in
  front of civil courts e.g. in inheritance,
  missing persons, disputed paternity.

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• 3- Criminal identification
• a)It is the job of the police.
• b)It comprises dactylography, photograph, lip
  prints and foot prints and by DNA.
• c)It is required in cases of murder, rape,
  impersonation, interchange of newborn.

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Role of forensic doctor in case of unidentified
bodies and/or assailants

• 1. Take identification photos.
• 2. Chart and x-ray the teeth.
• 3. Fingerprint the body.
• 4. Perform total body x-rays.
• 5. Retain tissue for DNA.

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• 6. Bite marks should be
• a- First swabbed to obtain saliva.
• b- Then they should be recorded by color
  photography.
• c- If theres an impression, measurements and
  latex cast can be made of it to be matched
  against the teeth of a suspect or a victim.

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• 7. Keep the clothes in a paper bag after allowing
  it to dry in air.
• 8. Take a swab from any obvious stain.
• 9. Collect any foreign hairs and obtain finger
  nail scrapping.

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Summary of Identification

• The points to be noted for identification-
• 1. Race.
• 2. Sex.
• 3. Age.
• 4. Complexion and Features.
• 5. Hair.

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• 6. a)Dactylography or Galtons system of Finger
  Prints
• b) Lucards System or Poroscopy.
• c) Lip prints.
• d) Foot Prints.

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• 7.Deformities and Birthmark.
• 8.Scars.
• 9.Tattoo marks.
• 10.Occupational marks.
• 11.Hand Writing.
• 12.Clothes, ornaments and articles in pocket.
• 13.Speech, Voice and language.
• 14.Gait.
• 15.Manners and Habits.
• 16.Mental power, memory and education.
• 17.Stature and weight.
• 18.Teeth, Dentures, filled cavities.
• 19.Genetics.

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GALTON SYSTEM OF DACTYLOGRAPHYFingerprints

• The most accurate and reliable method of
  identification.
• A finger print means an impression made by the
  ball of the finger.
• It is based on the principles that the skin of
  the balls of the fingers and thumb is covered
  with papillary ridges with pores of the sweat
  glands.

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Types of fingerprints

1. Arches.
2. Loops.
3. Whorls .
4. Composite.

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• Loop 60-70 of fingerprints patterns are loops.
  These are the most common fingerprint pattern.

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• Whorl 25-35 of fingerprint patterns are whorls.
  Whorls have at least two deltas and a core. Any
  fingerprint pattern that contains equal or more
  than 2 deltas will be a whorl pattern.

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• DELTA
• The point on a ridge at or in front of and
  nearest the center of the divergence of the type
  lines.
• The delta area is located as a triangular area
  where the ridges radiate outward in three
  directions.

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• Arch Only a few, that is close to 5 have this
  type of fingerprint. An arch doesnt have any
  delta lines, or cores.
• .

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GENETIC MARKERS

• Is a gene or DNA sequence with a known location
  on a chromosome that can be used to identify
  individuals or species.

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• Analytical methods to detect different types of
  genetic markers

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• The human ABO blood groups were discovered by
  Austrian-born American biologist Karl Landsteiner
  in 1901.
• The application of knowledge of the ABO system in
  blood transfusion practice is of enormous
  importance, since mistakes can have fatal
  consequences.

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• Typing of blood group systems
• They are red cell surface antigens that are
  permanent throughout life except some temporary
  changes after blood transfusion, so dont do
  blood grouping except after at least 3 months
  post-transfusion.
• They include

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• ABO system
• There are 3 antigens (A,B,O) giving 4 phenotypes
  (A, B, AB, O) due to 6 genotypes (AA, AO, BB,
  BO, AB, OO).
• ABO system locus is located on chromosome 9.

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• Rh system
• It is present in 85-90 of persons hence they are
  expressed as Rh ve, the remaining are Rh -ve.
• Their specific locus is located on chromosome 1.
• There are 3 pairs of genes C,c , D ,d , E,e
  each gene codes for an antigen except d which
  means absence of D antigen.

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• The individual may be
• Rh v e due to presence of D antigen on RBCs
  (genotype is DD or D d).
• Rh-ve due to absence of D antigen on RBCs
  (genotype is d d).

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• Bloodstain evidence is most often associated with
  violent acts such as assault, homicide,
  abduction, suicide or even vehicular accidents.
  Analyzing the size, shape, distribution, overall
  appearance and location of bloodstains at a crime
  scene helps investigators by answering basic
  questions .

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• Typing of red cell isoenzymes
• Group of enzymes are present inside RBCs which
  catalyze various vital biochemical reactions.
  They show polymorphism (present in different
  forms in different people) hence the term
  isoenzymes. e.g
• 1-Acid phosphatase (AP). clinically useful tumor
  marker.( )
• 2-6 phosphogluconate dehydrogenase (6 PGD).(
  )
• 3-Carbonic anhydrase (CA).

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• Typing of serum protein systems e.g.
• Haptaglobins (HP).
• Transferrin (Tf).
• Protease inhibitor (PI). Immunoglobulin
  markers (Gm, Km).

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• Typing of hemoglobin
• Fetal hemoglobin (HbF) is present in the fetus
  and very young infants.
• Sickle cell hemoglobin (HbS)which is responsible
  for sickle cell anemia, it is almost present in
  blacks.
• HbC normally present in black people.
• Hb D, E, A (adult Hb).

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• HLA typing (Human leucocyte antigens or complex)
• It consists of protein substances (about 50
  antigens) on the surface of all cells including
  leucocytes on which they were first discovered.
• Coding genes for HLA antigens are assigned to the
  short arm of chromosome 6.

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DNA fingerprinting (DNA profiling, DNA typing

• DNA is the basic genetic material contained in
  all living cells(human, animal, plants, fungi,
  bacteria and viruses).
• It guides the cell in production of proteins.
• It is the material of which the chromosomes are
  made.

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Sources of Samples analyzed for DNA profiling

• DNA can be extracted from
• Blood (WBCs).
• Semen.
• Saliva (wet or dry) found on chewing gum
  cigarette butts, postage samples, human skin
  (bite, suckling, kissing) or clothes.
• Nasal secretions found in used handkerchiefs.

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• 5.Hair roots (hair shaft is typed for
  mitochondrial DNA) .
• 6. Skin cells found in fingernail scrapings,
  gloves, a cap or arm pit area of a shirt.

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• DNA profiling The identification of variable
  characteristics at one or more loci in an
  individual's DNA, and the comparison of those
  characteristics with other DNA samples to
  determine whether they could have the same origin.

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• Locus The site on a chromosome where a gene or
  other feature of the DNA is located. Each gene is
  presented by two alleles that may be similar
  (homozygous) or different (heterozygous).

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• embryo come from the mothers egg.
• The fathers sperm contributes only nuclear DNA.
• While older biological samples that lack
  nucleated cellular material, such as hair, bone
  and teeth can not be analyzed with STR and RFLP,
  but they can be analyzed with mtDNA .
• Comparing the mtDNA profile of unidentified
  remains with the profile of a potential maternal
  relative can be an important technique in missing
  person investigations.

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• A Short Tandem Repeat (STR) analysis is one of
  the most useful methods in molecular biology
  which is used to compare specific loci on DNA
  from two or more samples. A short tandem repeat
  is a microsatellite, consisting of a unit of two
  to thirteen nucleotides repeated hundreds of
  times in a row on the DNA strand. STR analysis
  measures the exact number of repeating units.
  This method differs from restriction fragment
  length polymorphism analysis (RFLP) since STR
  analysis does not cut the DNA with restriction
  enzymes. Instead, probes are attached to desired
  regions on the DNA, and a polymerase chain
  reaction (PCR) is employed to discover the
  lengths of the short tandem repeats.

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Medico-legal importance of genetic markers

• 1. Disputed paternity
• a - Conventional serologic tests can only
  exclude a man from being the father of a child.
• b -DNA finger printing it is possible to prove
  beyond any doubt whether a man is or is not the
  father of a child.
• Disputed paternity claims arise in the following
  
• When husband denies that he is the father of the
  child.
• In cases of rape or if child is born out of
  lawful marriage and the accused person denies.
• When a woman pretends pregnancy delivery and
  adopts a child for sake of inheritance.

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• 2. Immigration cases
• DNA finger print tests are done for immigration
  purposes to confirm the family relationships.

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• 3. Criminal cases
• Any stain (blood, semen or saliva) must be
  examined
• At the scene of a crime.
• In threatening letters traces of saliva from
  licking the envelope or stamp can be analyzed for
  its DNA profile and matched with the DNA pattern
  obtained from the suspect's blood sample.
• In sex crimes Identification of assailant could
  be done by examining semen or swabbed bite marks
  for grouping (if he is secretor) as well as for
  DNA.

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• 4. Identification of a missing person
• 5. Study of anthropology and ancient history
• From mtDNA in Egyptians mummies and other ancient
  human remains.
• 6. Disputed maternity
• When children are mixed in hospitals
  mitochondrial DNA is done.

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• 8. In mass disaster
• To help identification of people or remnants of
  bodies provided that reference samples are
  available.

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Estimation of age from bones

• The age of an individual can be determined from a
  combination of data provided by
• A. Skull.
  B. Mandible and teeth.
• C. Appearance of ossify centers.
  D. Union of epiphyses.

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Skull
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• Dimensions
• In mature infant the circumference of the head is
  13 inches. Its length is 5 inches and its width
  is 4 inches.

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• Fontanelles
• Posterior fontanelle is closed at full term,
• Anterior fontanelle is closed at about 18-24
  months after birth.

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• Sutures
• The condylar portion of the occipital bone
  fuses with the squamous portion at 3 years and
  with the basal portion at 5 years.
• Frontal suture closes at 3-5 years (except in
  negroid skull where it persists).
• The basioccipital and basisphenoid suture closes
  at 23 years.

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• The sagittal suture starts to close from the
  inner aspect at 25 years and is completely closed
  from the outer plate at about 30 years.
• The coronal suture closes about the age of 40
  years.
• Lambdoid suture closes about the age of 50
  years.
• At the age of 70 years, all skull sutures are
  closed and faint except the suture between the
  temporal and parietal bones which remains open
  until old age.

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• Mandible and teeth
• a) Mandible
• In infants, the angle between the body of the
  mandible and the ramus is obtuse (small mandible
  that caries the milk teeth).
• The mental foramen near the lower border.
• In middle life, the angle becomes right. The
  mental foramen is midway between upper and lower
  border.
• The senile mandible has an obtuse angle again,
  the teeth are lost and the alveolar margins are
  absorbed. So, the mental foramen is higher.

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• Milk teeth (temporary, primary or deciduous)
• They are twenty in number (4 incisors, 2 canines
  and 4 molars in each jaw).
• They are small, narrow, bluish white and
  delicate.
• The first dentition (central incisors) begins at
  the 6th month.

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Eruption  
Central incisors at 6th month  
Lateral incisors at 9th month  
First molars at 12th month  
Canines at 18th month  
Second molars at 24th month  
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• Permanent teeth (secondary)
• They are thirty two in number (4 incisors, 2
  canines, 4 premolars or bicuspids and 6 molars in
  each jaw).
• They are big, broad, heavy and strong. Permanent
  incisors have usually serrated edges.
• The first erupted permanent tooth is the first
  molar (at 6 years)

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First molar 6 years
Central incisor 7 years
Lateral incisor 8 years
First bicuspid 9 years
Second bicuspid 10 years
Canine 11 years
Second molar 12 years
Third molar(wisdom teeth) 18-25 years
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Appearance of ossify centers

• Ossific center of the head of femur appears at
  end of the first year.
• Ossific center of the lower end of the radius
  appears at the end of the second year, it reaches
  2/3 the breadth of the epiphysis at 7 years.
• Ossific center of the upper end of the radius
  appears at 6 years.
• Ossific center of the upper end of the ulna
  appears at 12 years.

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Union of epiphyses

• 1) In the upper limb
• A . Humerus
• The trochlea unites with the capitulum at 14
  years. They unite with the shaft at about 15
  years.
• Lateral epicondyle unites with the shaft at about
  16 years. Medial epicondyle unites with the shaft
  at about 17 years.
• Head of humerus unites with the shaft at about 20
  years.

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• b. Radius and Ulna
• The upper end of the ulna and radius unite with
  the shaft of its bone at about 16 and 17 years
  respectively.
• The distal ends of both bones (wrist) unite with
  their shafts at about 20 years.

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• c. Hands
• The epiphyses of the metacarpals and phalanges
  unite with their shafts at about 18 years.

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• 2) In the lower limb
• a. Femur
• The lesser trochanter, greater trochanter and
  head of the femur unite with the shaft at about
  16, 17 and 18 years respectively.
• The lower end unites with the shaft at about 21
  years.

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• b. Tibia and Fibula
• Lower end and upper end of the tibia and fibula
  unite with the shaft at about 18 (ankle) 21
  years respectively.

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• c. Feet
• The epiphyses of the metatarsals and phalanges
  unite with their shaft at about 18 years.

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• 3) Pelvis
• a. Hip bone
• Pubic ramus unites with the ramus of the ischium
  at about 6 years.
• Ilium, ischium and pubic bones unite at about
  14-15 years resulting in disappearance of the
  Y-shaped suture in the acetabulum.
• The epiphysis of the ischial tuberosity unites at
  about 21 years.
• The epiphysis of the iliac crest unites at about
  23 years.
• b. Sacrum
• Fusion of sacral segments starts between 20 24
  years and completed at about 25 years.

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• 4) Hyoid bone
• The greater cornu of the hyoid bone unites with
  the body at about 40 years.

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• 5) Sternum
• Xiphoid process unites with the body of the
  sternum at about 40 years.
• The manubrium fuses with the body at about 60
  years.

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• 6) Clavicle
• - The acromial end unites with the shaft at about
  18 years.
• - The sternal end unites with the shaft at about
  23 years.

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• Home work
• Describe in short the ages of medico-legal
  importance?