@His4Life
I can hardly believe I need to explain this to a black woman, who of all people should know better. Is this a troll of some sort that hacked her account? Maybe, but anyway...
Let's use a metaphor, shall we? Say there is a white breed of flower and a red breed of flower. In scenario A, the red flower's genes are dominant over white, usually denoted in Mendelian genetics as uppercase R. The white flowers are recessive, or lowercase r. When the two flowers cross-pollenate, they produce only heterozygous (Rr) offspring, which are all red and are indistinguishable from the red flowers that spawned them, except on the genetic level. There is no visible evidence that they are part white. However, if you breed two heterozygous Rr plants together, you get this:
image
Two heterozygous plants are capable of producing pure-blooded red flowers 1/4 of the time, more heterozygous plants 50% of the time, and a pure white plant 25% of the time.
However, that's only if one trait is dominant over the other. For scenario B, the genes are NOT dominant over one another. Instead, both sets of genes are expressed. (Human blood types work this way, such as AB).
When the red and white flowers interbreed, they then produce pink flowers. Even though it's perfectly in between, pink can be seen as "closer" to red than it is to white, correct? That same bias is at work with skin tone. And, as I'm sure you've noticed, people that would have once been called Quadroons and Octoroons are progressively "whiter-looking" than their duskier forebears. This is a physical impossibility if one set of genes were dominant over the other; either you would be COMPLETELY black or COMPLETELY white, with nothing in between. And bizarre things would happen, like a black couple giving birth to blond-haired blue-eyed white babies, if they were both heterozygous. That simply doesn't happen.*
*Although, if you want to be picky, in extremely rare cases, atavisms, or genetic throwbacks, do occur, as well as duplications of the original mutations which produced distinctions between the races. This is so ridiculously rare, however, that it's not even relevant.
