Hair Phenotypes Americas, Australasian, Indo-European , Asian or Eastern Asian, Subequatorial African

 Sub-equatorial African Hair

Sub-equatorial African hair shafts are flattened and prone to tight curling. Many people classified by the US census Department as African American have this type of hair; however, many such citizens by now have antecedent from continents other than directly from Africa, again a reflection of the easing of social barriers.

 

The distribution of the African and African-like phenotype is strongly oriented toward the equator. Research indicates that although sub-saharan Africans are the most genetically diverse group on Earth, there is a strong selective pressure to produce this curly hair phenotype. This does not seem to support sexual selection as the sole or principal cause of the distribution. Further, peoples with no recent African lineage also express this phenotype at the  equator, possibly supporting a thermoregulatory function.

 

Individuals with African hair were forcibly transported to both the Americans in the 1800s and immigrated into Europe from post-colonial Africa in the twentieth Century. Of all the hair types, African hair suffers most from grooming issues due to its dense curl, and from breakage due to its shape. Man African women and women of African descent use heat or chemicals to straighten their hair for both practical and aesthetic reasons. This may result in damage. 

 

Asian or Eastern Asian Hair

Asian or Eastern Asian hair is circular and of wide diameter, with a tendency to straightness and rigidity. This phenotype has a large diameter (up to 150 microns), and is essentially straight and black.

 

However, not all Asian peoples have the classical straight or thick hair associated with the extreme northeast Asia Continent and inuit peoples of Alaska. The range of hair diameters stretches from 80 to 150, with a South-to-north bias of increasing diameter. 

 

Volume control is an issue, and chemical permanent procedures are still widely utilized as a method of control. From research, celebrity trend are the key driver for women and some men bleaching to achieve a change of hair color.

 

Indo-European Hair

This type of hair is more ovoid and has variable characteristics thin / straight to thicker and / or wavy/curly. This is more typical of those primarily of Dutch Origin mixed with Portuguese, British, French, Belgian, German and other countries of origin.

 The board group of Indo-Europeans shows an East-to-West bias of darkly pigmented, straight hair to thinner, lighter hair. Those from the Indian subcontinent have hair that is classically straight. In Europe a range of Straight, wavy, and curly hair occurs. The presence of pheomelanin pigment increases in the northwest of the Indo European area.

 

As human beings spread our around the world, arrival in Europe only occurred in the last 35,000 years. Low sunlight levels are regarded as the cause of the emergence of lightened skins, but the explanation for light hair is uncertain. Only 1.8% of humans have naturally light / blond hair, with the highest preponderance in Estonia.

Australasian Hair

Genetic evidence shows the aboriginal peoples, whose ancestors arrived in Australia some 50,000 years ago and remained isolated until Captain cook discovered their land, are direct descendants of the first modern humans to leave Africa, without any genetic mixture from other subgroups. Their highly pigmented skin reflects an African origin and a migration and residence in latitudes near the equator, unlike Europeans and Asians whose ancestors gained the paler skin necessary for living in northern latitudes. 

 

Based on the rate of mutation in DNA, geneticists estimate that the aboriginal peoples split from the ancestors of all Eurasians some 70,000 years ago, and that the ancestors of Europeans and East Asians split from each other about 30,000 years ago. Their hair is interesting in having features of subequatorial Africa but with a distinct loosening of the tight curl. Interestingly, some  aborigine children are born with blond hair.

 

Hair Phenotypes in  the Americas

The above proposed nomenclature is fall from all embracing, and is particularly problematic for the Americas. The indigenous peoples of both North and South America were descendants of Inuits, who entered Alaska across the Bering strait some 12,000 years ago and presumably had hair characteristics of Asian peoples. Waves of immigration of peoples from particularly Europe and Africa have produced increasing complexity and homogeneity, with wider gence sharing.