Identification Methods and Classifications
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Questions and Answers

What percentage of fingerprint patterns are classified as loops?

  • 60-70% (correct)
  • 85-90%
  • 25-35%
  • 5-10%

    • Which fingerprint pattern is characterized by having at least two deltas and a core?

  • Loop
  • Composite
  • Whorl (correct)
  • Arch

    • What must be considered when typing blood group systems after a transfusion?

  • Wait at least 3 months post-transfusion for accurate results. (correct)
  • Blood grouping is only effective if done in a lab setting.
  • Transfusions do not affect future blood group typings.
  • Typing can be done immediately after transfusion.

    • Which of the following represents the genotype for Rh-negative individuals?

    <p>d d</p> Signup and view all the answers

    Which of the following statements about arches as a fingerprint pattern is accurate?

    <p>Only about 5% of fingerprints are classified as arches.</p> Signup and view all the answers

    What does complete identification entail?

    <p>Absolute fixation of the individuality of a person.</p> Signup and view all the answers

    Which of the following methods is NOT part of criminal identification?

    <p>Victim's eye witness testimony</p> Signup and view all the answers

    What is the purpose of legal identification?

    <p>To provide a complete description of an unknown dead body.</p> Signup and view all the answers

    Which characteristic is NOT typically noted for identification purposes?

    <p>Favorite food</p> Signup and view all the answers

    What is a crucial first step when handling bite marks for identification?

    <p>Swab to obtain saliva.</p> Signup and view all the answers

    Study Notes

    Identification Definition

    • Identification is recognizing an unknown person (living, dead or remains) through distinguishing features.

    Identification Classification

    • Complete: Absolute fixing of a person's individuality.
    • Partial: Ascertaining only some facts (e.g., sex, age, race, stature) about a person.

    Types of Identification

    • Legal identification: Complete description of an unknown dead body to identify the person later. Required in cases of fires, explosions, accidents, discovering bodies on roads, in fields, railway compartments or water, or for decomposed, mutilated, or skeletal remains.

    • Personal/Civil identification: Recognizing a living or dead person using relatives, friends, witnesses, or in civil courts (inheritance, missing persons, disputed paternity).

    • Criminal identification: Done by law enforcement, including dactylography (fingerprinting), photography, lip prints, foot prints, and DNA analysis. Required in murder, rape, impersonation cases, or newborn exchanges.

    Forensic Doctor's Role

    • Take identification photos.
    • Chart and x-ray teeth.
    • Fingerprint the body.
    • Perform total body x-rays.
    • Retain tissue for DNA.
    • Bite marks are swabbed to get saliva and photographed. Measurements and latex casts can be made to compare with suspects/victims.
    • Clothes are kept in paper bags to dry.
    • Any obvious stains are swabbed.
    • Foreign hairs and fingernail scrapings are collected.

    Summary of Identification Points

    • Race
    • Sex
    • Age
    • Complexion and Features
    • Hair
    • Dactylography (fingerprinting), Lucards System/Poroscopy, lip prints, foot prints, DNA
    • Deformities and birthmarks
    • Scars, tattoo marks
    • Occupational marks
    • Handwriting
    • Clothes, ornaments, articles in pockets
    • Speech, voice, language
    • Gait, manners, habits
    • Mental power, memory, education
    • Stature, weight
    • Teeth, dentures, filled cavities
    • Genetics

    Galton System of Dactylography

    • Most accurate and reliable identification method.
    • A fingerprint is made by the ball of the finger, based on papillary ridges and sweat gland pores.
    • Types of fingerprints: Arches, Loops, Whorls, Composite.
    • Common pattern is Loop (60-70%).
    • Whorl (25-35%): has two or more deltas and a core.
    • Delta: point on a ridge near the center of divergence of type lines, forming a triangle.
    • Arch (5%): has no delta or core lines.

    Genetic Markers

    • Gene or DNA sequence at a specific location on a chromosome to identify individuals/species.

    Analytical Methods for Genetic Markers

    • Methods to detect various types of genetic markers are analyzed.

    ABO Blood Group System

    • Discovered by Karl Landsteiner in 1901.
    • Crucial in blood transfusions (wrong blood types can be fatal).
    • 3 antigens (A, B, O) lead to 6 genotypes (AA, AO, BB, BO, AB, OO) resulting in 4 phenotypes (A, B, AB, O).
    • Located on chromosome 9.

    Rh System

    • 85-90% of people are Rh positive (+ve), the rest are negative (-ve).
    • Located on chromosome 1.
    • 3 pairs of genes (C, c, D, d, E, e), except 'd' which marks the absence of D antigen.
    • Rh +ve: D antigen present on RBCs (genotype DD or Dd).
    • Rh -ve: D antigen absent on RBCs (genotype dd).

    Bloodstain Evidence

    • Often associated with violent crimes (assault, homicide, abduction, suicide, accidents)
    • Analyzing bloodstain size, shape, distribution, appearance, and location helps investigators.

    Red Cell Isoenzymes

    • Groups of enzymes inside RBCs that catalyze vital biochemical reactions.
    • Show polymorphism (different forms in different people). Examples: Acid phosphatase (AP) , 2-6 phosphogluconate dehydrogenase (6 PGD) and Carbonic anhydrase (CA).

    Serum Protein Typing

    • Haptaglobins (HP).
    • Transferrin (Tf).
    • Protease inhibitor (PI).
    • Immunoglobulin markers (Gm, Km).

    Hemoglobin Typing

    • Fetal hemoglobin (HbF): present in fetus and newborns.
    • Sickle cell hemoglobin (HbS): causes sickle cell anemia and found mostly in blacks.
    • HbC: found mostly in blacks too.
    • Hb D, E, and A (adult Hb).

    HLA Typing (Human Leukocyte Antigens)

    • Consists of proteins (about 50 antigens) on the surface of all cells (including leukocytes).
    • Coding genes are on the short arm of chromosome 6.

    DNA Fingerprinting (DNA profiling, DNA typing)

    • Basic genetic material present in all living cells (humans, animals, plants, fungi, bacteria and viruses).

    • Guides cells in producing proteins and is the material of chromosomes.

    • DNA can be extracted from blood, semen, saliva, nasal secretions, hair roots, skin cells, and more.

    • DNA profiling identifies distinctive characteristics (at one or more loci) and compares them with other samples to see if the same origin source.

    • Locus: The site of a gene or other feature of DNA on a chromosome.

    • Each gene has two possible alleles (homozygous if similar alleles, heterozygous if different alleles).

    • Disputed paternity: DNA fingerprinting definitively proves or disproves paternity, while conventional methods can only rule out paternity. Claims arise in cases of rape, unmarried pregnancies, and inheritance cases.
    • Immigration cases: DNA fingerprinting confirms family relationships.
    • Criminal cases: DNA evidence can identify suspects or victims (semen, saliva, blood evidence at crime scene).
    • Missing persons: mtDNA can match unidentified remains to potential maternal relatives.
    • Anthropology and ancient history: mtDNA in Egyptian mummies and other ancient remains helps anthropological studies.

    DNA Profiling Methods

    • Short Tandem Repeats (STRs): measures the exact number of repeating units in specific loci in a DNA sample. A common method that differs from restriction fragment length polymorphism (RFLP) because it doesn't cut the DNA with restriction enzymes.

    Estimating Age from Bones

    • Derived from combined data from a skull, mandible and teeth, appearance of ossification centers and union of epiphyses.
    • Cranial bones: Frontal, Parietal(2), Temporal(2), Occipital(1), Sphenoid(1), Ethmoid(1).
    • Fontanelles: Posterior fontanelle closes at full term; Anterior fontanelle closes at about 18–24 months.
    • Sutures: coronal, sagittal, and lambdoid.
    • Mandible and teeth: appearance of the angle between the body and the ramus, location of the mental foramen, and presence/absence of teeth are important factors in determining age.
    • Milk teeth: temporary teeth; typically 20 in number (4 incisors, 2 canines, 4 molars)
    • Eruption times: eruption time(s) for milk teeth, and permanent teeth.
    • Appearance of ossification centers: In different bones (femur, radius, ulna)
    • Union of epiphyses: The upper/lower ends(epiphyses) of the bones unite with the shaft at different times in the upper and lower limbs, hands, feet, pelvis, hyoid bone, and sternum, and clavicle.

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    Identification PDF

    Description

    Explore the various methods and types of identification in this quiz. Learn about complete and partial identification, as well as legal, personal, and criminal identification techniques. Test your knowledge on how different situations require distinct identification processes.

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