Back in the Luisa Rey section, when Luisa is doing research on Swannekke, Fay Li makes an interesting choice of words. "Miss Rey is here […] to write an article on Swannekke anthropology" (3.30.5). Isaac Sachs responds, "We're a dull tribe" (3.30.6).
Hundreds of years later, when Zachry asks Meronym how she can ride a horse, she says "she'd lived with a tribe called the Swannekke" (6.1.294). It's a small echo, but it's one of many reasons Meronym reminds us of Luisa Rey (and not just because Halle Berry plays both characters in the movie).
In the chronological timeline of Cloud Atlas, Meronym is the final character to bear the comet-shaped birthmark. Does this mean she's one (or more) of our previous characters reincarnated? We're not sure, but she does have a lot in common with Luisa Rey. Like Luisa Rey, Meronym is willing to put her life on the line for the truth—or as she calls it, the true-true. She takes risks (like climbing Mauna Kea) and conducts research. If Zachry's world had newspapers, Meronym would be perfect to write for one.
We mentioned at the end of the Zachry section that his story is a reboot of sorts, like history starting over. There's one major change this time around, though, and that's that people of dark skinned races aren't enslaved or discriminated against. Meronym and all the Prescients are described as "brewy-brown'n'black" (6.1.48). Not only are they not discriminated against, they also possess superior technology and have access to a larger array of knowledge than anyone else.
Even though Zachry suspects Meronym of having ulterior motives (probably in the same way that dark-skinned tribes suspected white-skinned Europeans of having ulterior motives… which they did), Meronym makes it perfectly clear that's not the case: "Smart'n'Civ'lize ain't nothin' to do with the color o' the skin, nay" (6.1.88). At least humans aren't making that mistake again.
One more thing: "Meronym" is a word, too. It means something that is a part of a larger whole, such as "hand" being a meronym of "arm." This points to one of the overarching themes of Cloud Atlas, which is that every one of us is a part of something much larger, something we may never truly understand.