One of the most noticeable things about your ethnicity may well be your hair. The way your hair grows and looks depends on the shape and size of your hair follicles, which contour and form the hair as it grows, and which are determined by your ethnicity. The thickness of hair depends on how many follicles a person has and the size of the follicles. If your follicles are small, you will have thin hair. If you have large hair follicles your hair is thick.
The texture of your hair can range from very curly to very straight. When hair follicles are round, this produces straight hair. Oval hair follicles result in curly hair. Ribbon-like flat-structured follicles cause the hair to be tightly coiled, which is the type of hair that is found most commonly among those of African descent. This type of hair is wiry but can often be dry because, although African hair produces a lot of sebum, which is protective oil, the tight curls prevent the oil from spreading out evenly along the hair fiber. Asian and Caucasian people do not produce as much sebum.
South-Asian and Hispanic
South-Asian hair, such as that from India, is usually dark and thick, and tends to be frizzy. Indian women like to wear their hair long. Regular moisturizing of the hair keeps it from breaking off. Hispanic hair tends to be wavy, curly or frizzy and also requires lost of moisturizer.
Asian hair is coarser and thicker than African American and Caucasian hair. It is nearly always circular in the cross section and straight. However, Asians have fewer follicles per unit area of skin than do Caucasians. African Americans also have less dense hair follicles than Caucasians.
American Indians and Eskimos
Eskimos, Native Americans and Mongoloid groups usually have hair that is textured but straight. Caucasian hair comes in all shapes and forms, and it is not unusual to see a curly-haired or wavy-haired Caucasian.
Woolly Hair Syndrome
Because African hair is brittle it is not easily grown long. When hair curls very tightly, the tight curls put stress at each turn in the fiber of the hair, and the hair can become fragile as a result and break easily. The tightly coiled hair of those of African descent results in more rigidity to the fiber, which makes the curls flex and coil along the ribbon, but there is no coiling or very little coiling from side to side. African textured hair is so unusual in Asians and Caucasians that when it does appear it is referred to as Woolly hair syndrome, which is tightly spiraled and dry. This syndrome runs in families and is not the result of racial mixing. No one knows why this occurs. It is known that woolly hair syndrome is inherited dominantly, meaning that only a single copy of the gene is needed from either the mother or father. Those of African descent usually carry two copies of the dominant gene. Interestingly, woolly hair in Caucasians tends to manifest with the curls merging whereas the curls on Africans lie in separate ringlets.
A study done at the Queensland Institute of Medical Research found genetic variations that cause hair to curl in those with European descent. This gene is called trichohyalin. The results indicated that 45 percent of European people have straight hair whereas 15 percent have curly hair and 40 percent have wavy hair. The odds of inheriting curly hair are approximately 90 percent, notes Professor Nick Martin, author of the research, and his colleague, Dr. Sarah Medland.
Those who have red hair have the least dense scalp growth in the Caucasian group whereas blonds have the most dense scalp growth and brunettes are somewhere in the middle.