vi types of skin color are there.
vi types of skin color are there.
how many types of skin color are there?
vi
the actual skin color of different humans is affected by many substances, although the single most important substance is the pigment melanin. melanin is produced within the skin in cells called melanocytes and it is the main determinant of the skin color of darker-skinned humans. the skin color of people with light skin is determined mainly by the bluish-white connective tissue under the dermis and by the hemoglobin circulating in the veins of the dermis. the red color underlying the skin becomes more visible, especially in the face, when, as consequence of physical exercise or the stimulation of the nervous system (anger, fear), arterioles dilate. color is not entirely uniform across an individual's skin; for example, the skin of the palm and the sole is lighter than most other skin, and this is especially noticeable in darker-skinned people.
human skin color
approximately 10% of the variance in skin color occurs within regions, and approximately 90% occurs between regions. because skin color has been under strong selective pressure, similar skin colors can result from convergent adaptation rather than from genetic relatedness; populations with similar pigmentation may be genetically no more similar than other widely separated groups. furthermore, in some parts of the world where people from different regions have mixed extensively, the connection between skin color and ancestry has substantially weakened. in brazil, for example, skin color is not closely associated with the percentage of recent african ancestors a person has, as estimated from an analysis of genetic variants differing in frequency among continent groups.
human skin color