Genetics finger printing practical

1. • Fingerprint identification has
played an important role in the
history of policing and forensic
science.
• The scientific study of fingerprint
and palm patterning is referred
to as “dermatoglyphics,” a term
that was invented in the 1920s.

2. • When this field was first developing at the turn of the 20th century, those who conducted
scientific research on fingerprints were preoccupied with the question of whether minute
anatomical differences in the fingerprints could be used to distinguish between different
“races.”
• Those who carried out these early anthropological studies of fingerprints were proponents of
ideas about race, eugenics, and biological determinism that were disparaging and abhorrent.
• While many of these ideas would be abandoned over time, dermatoglyphics researchers
would continue to investigate the different frequencies with which fingerprint characteristics
appear in different populations.
• Throughout the 20th century, a large amount of research would be done on the
anthropological, genetic, and medical aspects of fingerprint patterning.
Introduction

4. • While researchers in dermatoglyphics were not actually concerned with using fingerprints to
determine one’s ideal occupation, they were interested in examining skin ridge patterning of
the fingers and palms in order to reveal various other things about a person.
• Over the 20th century, for example, much research would be devoted to correlating
fingerprint and palm patterns with particular congenital or health conditions such as Down
syndrome
• Another way that dermatoglyphics research was different from personal identification was
that researchers in this field often analyzed fingerprints at the level of groups and
populations.
Introduction

6. • During the 1950s and 1960s, for example, researchers examined the relationship between various medical conditions
and observed abnormalities in fingerprint and palm patterning.
• Dermatoglyphics [that is, palm and fingerprint patterns] provide a tool of unique value for human geneticists and
physical anthropologists. The configurations are established long before birth and are not altered by age (except in size),
and post-natal environmental circumstances.
• The dermatoglyphic science is based on two major facts:
1. the ridges are slightly different for different fingers and no two persons, not even monozygotic twins, show exactly
similar fingerprint patterns
2. the ridges are permanent throughout life and they survive superficial injuries and also environmental changes after the
21st week intra-uterine life.
• The formation of the three patterns were not primarily linked to skin formation but rather limb and finger formation.
Introduction

7. • The ARCHES are the simplest and least frequent pattern, which pass across the finger with slight bow distally.
• They may be subclassified as “plain” when the ridges rise slightly over the middle of the finger or “tented” when the
ridges rise to a point.
• The LOOP PATTERN has a triradius and a core.
• A triradius is a point at which three groups of ridges coming from three directions meet at angles of about 120°.
• The core is essentially a ridge that is surrounded by fields of ridges, which turn back on themselves at 180°. Loops can
be either radial or ulnar.
• A finger possesses a radial loop if its triradius is on the side of the little finger for the hand in question, and the loop
opens toward the thumb. A finger has an ulnar loop if its triradius is on the side of the thumb for that hand, and the
loop opens toward the little finger.
• The WHORLS are the patterns so constructed that the characteristic ridge courses follow circuits around the core.
• The shape of the pattern area may be either circular or elliptical.
• This pattern has two triradii with the ridges forming various patterns inside.
Different Pattern of Fingerprints

14.  The digital and palmar dermatoglyphic features of
Down's syndrome are:
• excess of ulnar loops
• occasional radial loops on the 4th and 5th digits
• distally located axial triradii
• wide atd angles
• excess of patterns in the hypothenar and III interdigital
areas.
 Dermatoglyphics of the sole in Down's syndrome are
characterized by an arch tibial in the hallucal area.
 In addition to the dermatoglyphic features, there is
high incidence of the simian line in the palm.