Why African palm are lighter than other parts of their body?

Answer 1

The correct answer would be because of a protein known as dickkopf 1, or DKK1.

Investigators looked at the dermis, the layer on the skin beneath the epidermis (outer layer), and a certain type of cell within this layer, called a fibroblast. They found that the fibroblasts in the soles and palms secrete higher levels of a protein known as dickkopf 1, or DKK1, than the fibroblasts in the dermis at other body sites. It is believed that the rich source of DKK1 in these areas affects the epidermal layer above it and creates the physical characteristics of thickened, paler skin.

DKK1 reduces skin pigmentation by suppressing the development and action of pigment producing skin cells called melanocytes. It also reduces the transportation of this pigment from melanocytes to the target skin cells for melanin (keratinocytes).

DKK1 also thickens the epidermis by increasing the number of skin cells and their density. Three genes affected by DKK1 - keratin 9, αKLEIP and β-catenin - have been found to cause this thickening. Keratin 9 reinforces the skin against physical impact, αKLEIP aids in cell division (multiplying) and makes cells smaller and, finally, a reduction in β-catenin is also possibly involved in cell contraction (making the cells more compact).