However, people inhabiting the Indian subcontinent are mainly Caucasian and their skin color ranges from light brown to quite dark. Even within Europe, skin color ranges from very pale to brown. Other substances can in minor ways affect skin shading, such as the colored fibers of the protein elastin and the pigment carotene. However, once again we all share these same compounds, and the principles governing their inheritance are similar to those outlined here. Eumelanin is very dark brown, phaeomelanin is more reddish.
People tan when sunlight stimulates eumelanin production.
Redheads, who are often unable to develop a protective tan, have a high proportion of phaeomelanin. Most of this DNA is in the nucleus of each cell, but some is contained in mitochondria, which are outside the nucleus in the cytoplasm. Sperm contribute only nuclear DNA when the egg is fertilized. Mitochondrial DNA is inherited only from the mother, via the egg. The creative intelligence behind such a thing is mind-boggling.