Ok. You asked for it.
The first little excursion we'll be taking is to the book of Genesis. (Why start with the end when you can start at the beginning?

)
EXHIBIT 1) Noah curses his grandson, Canaan, because Ham, Noah's son committed some kind of moral offense. So, from the line of Ham and Canaan, we supposedly later see the Canaanites come forth in the Old Testament narratives. Then, the Israelites come out of the line of Shem, one of Noah's two other sons. (Genesis 9:22-27)
Now, JGG, just with EXHIBIT 1 alone, would you say that with the narrow time implications within the genealogical connections presented therein that the Israelites are indeed a separate "race" from the Canaanites? [I wouldn't.] Moreover, would Noah's curse upon Canaan designate some "physical" difference in the Canaanite's appearance by which they would be later targeted for discrimination by the Israelites? [The answer is "no," unless you think being taller and stronger than an Israelite is something that would count as a racial characteristic. But, I get ahead of myself in saying this. We'll save this nuance for an upcoming Exhibit.]
1500 years? I don't see why not. Before they became distinct ethnicities 500 years ago, the Hutu and Tutsis were one people. Creole is a distinct ethnicity, and they've only been around for about 300 years.
More importantly, we should note that we're dealing with a narrative here in Genesis that is essentially a product of a later time and wrapped up contextually as a background explanation as to "why" the Canaanites were being picked on by the Israelites during the Conquest. It looks to me like the implication build into this initial 'explanatory' text is of a ... moral quality.
Should we note that? Why?
Shall we move on to EXHIBIT 2? [And yes, there will be several exhibits.

]
By all means...