Some Mormons believe the GOD cursed Cain with black skin and a flat nose. However, the "mark" was set upon Cain before the flood. In that flood all flesh perished except for Noah, his wife, his three sons, and their wives. If the curse upon Cain was dark skin, the only way the race could have survived was for Noah to be a direct descendent of Cain. However, Noah's genealogy didn't come from Cain, but from Seth. This is all clearly stated in Genesis 5:3-32.

So where do all the races come from? If we are all descendents of Adam and Eve, shouldn't there only be one race? Well, what is race? Reuters news service ran the following article that was written by Maggie Fox:

Science may have caught up with the Bible, which says that Adam and Eve are the ancestors of all humans alive today.

Peter Underhill of Stanford University in California remarked on findings published in the November 2000 issue of the journal of Nature Genetics . . . Geneticists have long agreed there is no genetic basis to race - only to ethnic and geographic groups. "People look at a very conspicuous trait like skin color and they say, 'Well this person is so ' . . . but that's only skin deep." Underhill said "when you look at the level of the Y chromosome you find that, gee, there is very little difference between them. And skin color differences are strictly a consequence of climate."

So lets look at the question again, What is race? According to a recent Webster's Dictionary, race, as it applies to mankind, is

1 a: a family, tribe, people or nation belonging to the same stock.
1 b: a class or kind of people unified by a community of interests, habits, or characteristics.
2: a division of mankind possessing traits that are transmissible by descent and sufficient to characterize it as a distinct human type.

So if enough of the same people from the same area have children who then continue to have offspring with those same people from that same area, they will have similar traits. That sounds like a large scale version of what is typically said at family gatherings - how so and so looks so much like their parents, uncles, aunts, grandparents, etc.