And the LORD God formed man of the dust of the ground... Genesis 2:7
"Scientists have discovered that an important step in the production of
melanin requires a protein called the melanocortin 1 receptor (MC1R). 
This protein determines which color pigment (eumelanin or pheomelanin)
will be produced. The MC1R protein is on the surface of the cell, where
it binds to another protein called melanocyte-stimulating hormone (MSH).
This hormone is produced in the pituitary gland, which is a small
structure near the center of the bottom of the brain. Mutations in both
the hormone and the receptor have been linked to changes in the amount
and type of melanin that is produced.
For example, individuals with a
loss of function mutation for MC1R may not only have red hair and fair
skin but also skin that would not tan very well. Such individuals make
little if any eumelanin but instead make the pheomelanin, which is the
reddish-brown pigment. Albinism, where little if any pigment is made,
results from mutations in another gene that prevents pigment production
altogether.
Often when people consider skin, they think in simplistic terms (red,
yellow, black, white) and fail to recognize the wide range of skin tones
found in humans.
Across the African continent, among those who would be
called “black,” some are darker and some are lighter. Similarly, among
those across Europe that would be considered “white,” some are darker
and some are lighter. These results, when taken together, would imply
that Adam and Eve likely had higher levels of melanin
production and thus darker skin. Since genes linked to lighter color
appear to be mutations and polymorphisms with significant variability,
it suggests that lighter skin colors came later among their descendants,
perhaps even after Noah’s flood." AIG