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(Above and below)
Melanins in varying proportions and concentrations.
Differences in
skin color
Eumelanin is the commoner and more dominant pigment of the two, particularly
in hair. Most of the world's people have black hair, but skins that range
from very fair to black.
Skin color and hair color tend to go together
and may reflect our ancestors' adaptation to their environment. Scientists
believe that the earliest humans originated hundreds of thousands of years
ago in an area
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Although of
Danish nationality, this man is of mixed Caucasian and African descent.
His skin color, as well as other characteristics, result from his genetic
make-up.
now found in the African continent. The gradual evolution of the human
race continued along different lines, until there were essentially three
different ancestral racial groups:
- Asian - Oriental peoples
- African - people of direct African descent.
- Caucasian - including the people of north-western Europe and also
very dark-skinned Indians
Melanin production in skin varies in the three racial groups. 'Black' skins
do not contain any more melanocytes than white ones do. But there
are differences in the melanin granules in the differently colored
skins. In black skins the granules are larger, whereas in white skins they
are less obvious.
- In Asian people, the melanosomes are relatively large in size, and
are distributed within the skin cells as a mixture of single and complex
forms.
- In African skin the melanosomes are even larger; they are heavily
pigmented and scattered singly throughout the keratinocytes.
- In white Caucasian skin the melanosomes are smaller and have less
melanin; they are distributed as clumps in keratinocytes.
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