Scouts relationship in quotes chapter 1

"Well how do you know we ain't Negroes?"

"Uncle Jack Finch says we really don't know. He says as far as he can trace back the Finches we ain't, but for all he knows we mighta come straight out of Ethiopia durin' the Old Testament."

"That's what I thought," said Jem, "but around here once you have a drop of Negro blood, that makes you all black." (16.78-81)

Explanation:

Jem and Scout here try to figure out how society divides people up into races, and what happens when those divisions break down. As kids who don't yet simply accept the existing system as the Way Things Are Just Because, they can see that the "one-drop rule" doesn't really work unless the origin of every drop of a person's blood (or every gene in their DNA, to update their science) can be accounted for, and why is one drop of black blood able to overwhelm several gallons of white blood anyways?