The first part doesn't really ring any bells for Shephard. He's from a big family, from a long line of big families. Saying somebody further back up the tree had some kind of talent in the blood is like saying the family's related to a dead President or the English royal family- interesting, but what difference does it make?

The second part, though-

"Only," he says firmly. "Not last. I ain't never gonna be the last, sir. Only."