Genetically inherited traits often have a clinal distribution. That is to say there is a continuous, progressive gradation moving from one geographic region to another. … Such patterns can result when selective pressures differ from one region to another and when people mate mostly with their immediate neighbors.

What are examples of clinal distribution?

One easily visible example of a clinal distribution seen worldwide is the patterning of human variation in skin color. Whether in southern Asia, sub-Saharan Africa, or Australia, dark brown skin is found.

Is hair a clinal distribution?

The covariation of hair form and skin color are an exception to the pattern of clinal discordance. Hair on the head varies, and for a biological reason—spiral and wooly hair insulates the head from ultraviolet radiation.