What’s YEC explanation for the emergence of races?

Well i remember reading in a book an explaintion for it, but i do not remember much of it except one point. The main point was that adam and eve must have been in middle, as in a brown colour. Since all humans are essentially just differnt shades of the same colour, they had all of the genes nessisary for every possible skin colour. Im not going to go into detail about why, but it seems that this is happending right now in India. Even within the same family, you can get brother who is very dark, a sister who is very light and all thats inbetween.