Categories Anthropology

9.5 biological basis of racial classification, racial differentiation and race crossing in man.

Racial classification

Racial classification is given to a group of individuals, who share a certain number of anthropological traits, which is necessary such that they are not confused with others. There are two aspects to distinguish people based on phenotypic and genotypic traits.

  • Phenotypic Traits: Phenotypic traits are those physical characteristics of an individual, which may be examined:

These are of two types:

  • Indefinite Physical (Phenotypic) Traits and
  • Definite Physical (Phenotypic) Traits

Those physical traits which are observable but immeasurable to any measurement are called indefinite physical traits, such as the colour of skin, hair and eyes. Hence they can only be described. Following are some of the indefinite physical traits:

Skin Colour: From the very beginning, anthropologists have used skin colour as one of the most important distinguishing characteristic. Usually, on the basis of skin colour people differentiate between the white, yellow and black races. Recently, Spectrophotometry has been made as the basis of an objective and accurate measurement of the colour of the living human skin. Of the colour of the skin the following distinctions are made:

  • White skinned people or Leucoderms, e.g. Caucasian
  • Yellow skinned people or Xanthoderms, e.g. Mongolian
  • Black skinned people or Melanoderms, e.g., Negroes

Hair: In racial classification, the characteristics of hair, viz., hair form, colour, texture and abundance have been most frequently observed. Besides, cross section and hair whorls have also been used in certain All these hair traits are well defined and classified by anthropologists.

Eye: The characteristics of the eye, particularly the eye opening, eye fold and eye colour have been utilised in distinguishing the racial groups.

Nose: Nose is an integral part of the face and an independent entity whose attributes are comparable. Mainly, the descriptive elements of the nose may be observed and recorded in the following manner:

  • Nasal depression : None, shallow, medium, deep
  • Nasal bridge: Straight, concave, convex, Concave-convex
  • Nasal tip: Sharp, Medium, thick, bulbous
  • Nasal septum: Sloping upward, horizontal and sloping downward.
  • Disposition of the nares: High and narrow, medium broad, broad and flaring.

Lips: In humans, lips bind the oral fissure or the mouth opening. This trait is peculiar in man. It is generally observed that changing moods affects the position of the lips in four different ways: open and shut, foreword and backward, up and down, tense and slack on the basis of thickness of the lips, anthropologists distinguished humans into four groups, viz., thin, medium, thick and very thick lips.

Face form: Human face has distinguishable characteristics, which help to identify individuals. On the basis of conformation of the face,predominantly the hair line, the form of the jaw and the forehead, the form of the face may be determined. Poch has distinguished ten facial types, viz., elliptic, oval, reversed oval, round, rectangular, quadratic, rhombic, trapezium, inverted trapezium and pentagonal .

Ear: Ears are individually characteristic and have a number of peculiarities in ear forms. The external ear form may be classified into six types, viz., macaques form, cercopithecinae form, Darwinian point, Darwinian tubercle, vestigial Darwinian tubercle and without Darwinian tubercle.

The ear lobes are one of the most important features of individual characteristics. The ear morphology varies on the basis of ear lobe. The ear lobe is much developed in European and Mongoloids. The attached ear lobe is more primitive feature than the free lobe.

Definite Physical (Phenotypic) Traits

Definite physical traits are those, which can be measured with the help of anthropological methods and instruments. The following are definite physical traits:

■ Stature: Different races are distinguished on the basis of differences in stature. Martin has classified stature in the following manner:

Pygmy Upto 129.0 cms.
Very short 130.0 149.9 cms.
Short 150.0 159.9 cms.
Below medium 160.0 163.9 cms.
Medium 164.0 166.9 cms.
Above Medium 167.0 169.9 cms.
Tall 170.0 179.9 cms.
Very tall 180.0 199.9 cms.
Giant 200.0 and above

Head form: Anthropologists have adopted a method for classifying the head form based on the ratio of the maximum breath and maximum length expressed as cephalic index. On the basis of cephalic index, head is classified into three classes, i.e., Dolicocephalic, Mesocephalic and Branchycephalic.

Nose form: The nasal index is a good indicator to know the dimension of the nose. It is the proportion of the width of the nose to its length. Broca consider it as the best indicator in racial determination. Human population may be conveniently classified on the basis of nasal index as follows:

  • Leptorrhinae upto 9
  • Mesorrhinae 71 to      9
  • Chamaerrhinae or Platyrrhine 85 to      9
  • Ultra Chamaerrhine 100 and above

Face form: The proper evaluation of the face form can be possible with the help of Facial Index. It is an indicator of the proportion of the facial length to its breadth. The human populations may be conveniently classified on the basis of facial index as follows:

  • Hypereuryprospic upto 78.9
  • Euryprospic 79  to 83.9
  • Mesoprospic 84  to 87.9
  • Leptoprospic 88  to 92.9

Ear form: On the basis of the ratio between ear length and breath the ears has been classified into long and narrow in Mongoloid, short and wide in Negroes. The majority belongs to the intermediate type.

Other definite traits: There are various anthropometric measurements, which are used in racial classification, viz., bizygomatic breadth, proportion of limbs, chest and thigh circumference, etc.

Genotypic Traits: A new approach to classify human races is based on some genetic traits. The genotypic traits are as follows:

Blood Groups: The Blood groups (ABO, MN, Rh, Lutheram and Kid blood groups, Duffy Blood Group, P Blood Group and ABH secretor status, etc.) are used in racial classification. Their frequencies vary in different populations all over the world; these are used as genetic markers.

Dermatoglyphics: The dermatoglyphics traits are used in racial Each dermatoglyphic trait is inherited independently or polymorphically. These traits are not modified by environmental factors. In fact, Dermatoglyphics (Derma=skin; Glyphic=Carve) is the study where the ridge patterns on the skin of the fingers, palms, toes and soles are considered. The Dermatoglyphics trait include finger pattern types, Pattern Intensity Index, Pattern size, Palmar main line formula, Configurational area (Thenar interdigital area, Hypothenar area, Second, third, fourth, interdigital areas), Main Line Index, Palmar and finger – ridge counts, atd angle, etc.

Hemoglobin variants: The hemoglobin within the red cell also has its own variations in different populations of the world. The sickle-cell hemoglobin or hemoglobin S, Hemoglobin C, Hemoglobin D, hemoglobin E, Glucose-6-phasphate dehydrogenase (G-6 PD), Haptoglobins, Transferrins may be used in racial classification.

Some other variants: The ability to taste phenyl thio-carbamide, colour blindness, sweet glands, etc., are used for the racial classification.

DNA finger prints: The proper evaluation of racial classification can be possible with help of DNA finger printing. The genome of various populations may be used for such purpose.

Click here for details of each trait.

Racial differentiation

S.No Characters Caucasoid Negroid Mongoloid
1. Skin Colour Light reddish white to
olive brown. Some are
Brown to Brown Black.
Some are yellow-brown
Light yellow to yellow
brown. Some are reddish
2. Head Hair Light blond to dark
brown in colour, fine to
medium in texture,
straight to wavy in form
Brown-Black in colour,
coarse in texture, curly to
frizzly or woolly in form
Brown to brown black in
colour, coarse in texture,
straight in form
3. Head form Dolichocephalic to
branchycephalic. Height
is medium to very high
dolichocephalic. Height is
low to medium
Predominantly branchy-
cephalic height is medium
4. Body Hair
Moderate to profuse Slight Sparsely distributed
5. Face Narrow to medium broad Medium broad to narrow.
Prognathism is very often
Medium broad to very
broad. Check bones are
high and flat
6. Eye Colour is light blue to
dark brown
Brown to brown black Brown to dark brown.
Mongoloid eye fold is very
often present
7. Nose Leptorrhine                                 to mesorrhine, usually
bridge is high
Platyrrhine, usually
bridge is low
Mesorrhine to playtyrrhine,
usually bridge is low to
8. Chin Usually projecting Slight Medium
9. Lips Very thin to medium,
small aversion
Thick, much aversion Medium thickness with
aversion of membranous
often heavy integumented
10. Stature Medium to tall Very short to tall Medium to short
11. ABO Blood
Relatively                            high

incidence of A2

Relatively high incidence
of A2, comparatively high
incidence of B
High incidence of A1, very
low frequency of A2
12. Rh. Factor Highest frequency of Rh
Moderate frequency of
Rh negative
Rh negative is rare
13. Dermato-
glyphics pat-
tern intensity
Low Great dispersion ranging
from higher to lowest
Main Line
11.9.7 7.5.5 9.7.5
Main line Marked transversally
type-ii of D line
termination          quitefrequent
Longitudinal alignment Longitudinal alignment

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