Barbara Howard: Tomorrow, at this time, the royal wedding should be history. There's been pretty intense curiosity about Prince Harry's bride to be, the U.S. born Meghan Markle. Joining us in the studio is Gary Boyd Roberts. He specializes in royal lineage at the New England Historical Genealogical Society here in Boston.

Thanks for coming in Gary.

Roberts: Thank you.

Howard: Well, so on her father's side, your research has unearthed some New England connections. Can you talk a little bit about that?

Roberts: Yes, her father is partly Penn-German, and there's a sizable chunk of recent English, 19th and 20th century English, but she's 1/8th New England. And that 1/8th gets a lot of families that are in everybody's ancestry. Among the more famous ones: Pilsbury, as in the flour; Dow, as in Dow Chemical; Scribner, as in the publishing company; Crosby, as in Bing Crosby. Lots of other families and she's probably related to 30 to 50 million Americans.

Howard: And she's also related a few presidents, you said.

Roberts: Yes, to eight - Garfield and Arthur and Nixon and Ford, and the two Bushes, and Hoover and Coolidge. So it is definitely a New England derived Republican bunch. Being related to eight presidents is not unusual. Some of us have a dozen or more.

Howard: You?

Roberts: I have about nine.

Howard: OK. So she's also distantly related, you say, to her future husband and his mother, the late Princess Diana.

Roberts: Yes, and to the Queen. She has a descent through an early minister to Boston, from Edward I and Edward III. She also has distant connections to all the sovereigns of Europe via the last English ancestors of those sovereigns, and she is a seventeenth cousin of Harry and a 16th or 17th cousin of the Queen as well. All of the royal ladies are distantly related - the Queen Mother, Kate Middleton, and Megan Markel.

Howard: And to Harry himself she's a cousin?

Roberts: She's a 17th cousin.

Howard: When you say cousins, you mean …

Roberts: I mean somewhere between 8th and 12th – it means you have a 17th century ancestor, someone who came here in the 1620s, 30s, 40s in common. Millions of Americans are related and most of us have 500 or so famous distant relatives.

Howard: So she's not special in that regard?

Roberts: She's not special in that regard.

Howard: And now all this is through her father's side. Now Meghan Markle, like many Americans, has a complicated lineage - her mother, a descendant of slaves. Miss Markel has written movingly about her mother. Have you been able to track down any maternal lineage?

Roberts: No, I haven't really studied it. I have seen some items that appear to be well done, and various reporters and genealogists have gone down to Tennessee, Alabama, trace the slave ancestry as much as you can. You usually can't get much before the 1870 census. If the slaves are not freed, or if there are no plantation records, it's very hard to figure out which slaves took what surnames, and they were asked for a surname in the 1870 census. And so there were a lot of black people named Washington, Jefferson ,Madison.

Howard: Wisdom, I think is what she said her great-great-great-grandfather chose. She wrote about this - she said that he came up with his own name.

Roberts: That's very likely.

Howard: I have to ask: are you related to the royal family?

Roberts: Well, I have a descent from a Thomas Legan, who is something like a second cousin of various ancestors of Diana.

Howard: Thanks so much for coming in Gary.

Roberts: You're quite welcome. Thank you.

Howard: That's Gary Boyd Roberts, senior research scholar emeritus at the New England Historical Genealogical Society, talking about the distant relations of Meghan Markle, set to wed England's Prince Harry tomorrow.

And this little tidbit: back in 1981, just six days after the royal wedding of Prince Harry's parents, Prince Charles and the late Princess Diana, Meghan Markle was born in Los Angeles.