For 10 seasons and 106 episodes, Dr. Henry Louis Gates, Jr. has helped people research their family history in the PBS series Finding Your Roots With Henry Louis Gates, Jr., which has explored the often-tangled family trees of nearly 250 people. The show is the only PBS series to have seen its linear ratings increase over the past three years. It’s the network’s highest-rated regular show—and now, for Season 10, it’s finally nominated for an Emmy in the Outstanding Hosted Nonfiction Series or Special category.

“I’m humbled by the nomination. I never thought we would get it,” said Gates, a Harvard professor of African-American studies who helped create the show and hosted it for its entire run. He got the news in a Las Vegas hotel room where he was set to accept the Spingarn Medal, the NAACP’s highest award for black American service. “I was lying in bed, struggling with jet lag, thinking about my speech that night, and it was like my phone exploded.”

But he already knew that “Finding Your Roots” was attracting more and more attention over the course of its 10-year run. “I could see our popularity rise because people were stopping me in airports or on the street,” he said. “And that’s increased dramatically and exponentially every year for the last 10 years. What’s particularly gratifying to me is the fact that it’s ideologically neutral: The people who stop me are Republicans and Democrats, people from the left, people from the right, older people, younger people.”

“My favorite story is how a big guy in a MAGA hat came up to me. I jumped back and he said, ‘Professor Gates, I don’t like your politics, but I love your show. Can I have a selfie?'”

The show is an evolution of an earlier two-season series called “African American Lives,” which revealed the ancestry of black stars like Oprah Winfrey and Whoopi Goldberg. After receiving a letter from a woman of Russian Jewish descent who called him a “fat racist” for focusing only on black issues, he expanded his reach to people of all races – and around the same time, he brought on board CeCe Moore, a pioneer in the new science of genetic genealogy. Her work allowed the show to delve deeper into the genealogies of people whose paper trails have been wiped out, including people of Ashkenazi Jewish descent.

“By using autosomal DNA, she is able to bypass what genealogists call the ‘wall’ when the paper trail disappears,” he said. “And that was particularly satisfying to me.”

It also helps with what he calls a troubling lack of knowledge about our past. “One of the biggest surprises to me is that no one in this country knows anything about their ancestors beyond two or three generations — maybe great-grandparents. And I hope that introducing a person to their ancestors changes their relationship to both American history and world history. It makes you a player in major historical events, and that’s very exciting.”

The final episode of season 10 went in a new direction by asking “regular people” to submit videos for the show. They chose three from the 9,000 submissions, and the team’s four genealogists devoted as much time to those subjects as they did to celebrities. (“The ratings for that episode were the same as they were for celebrities,” he said.)

Other protagonists of the season included Valerie Bertinelli and Brendan Fraser, Bob Odenkirk and Iliza Shlesinger, Danielle Brooks and Dionne Warwick, and Wes Studi and LeVar Burton, the “Roots” star who was on the show’s wish list from the beginning. They join a decade of highlights that, for Gates, include using DNA evidence to discover that Larry David was the cousin of the man he impersonated on Saturday Night Live, Bernie Sanders, and identifying the grandparents of Andy Samberg and Téa Leoni, whose mothers were adopted and never knew their biological parents.

“This thing has grown and changed in ways I never imagined when I got up in the middle of the night to go to the bathroom in 2003 and had the epiphany that I could do a documentary series for PBS,” said Gates, who added that the show now has “a very long line” of more than 100 people who have agreed to be profiled on the series.

“It’s a deeply moving, deeply enriching experience,” he said. “And I’m just the messenger of the message. I’ll be convinced to my grave that one of the reasons I came to this earth is to help more and more people find their ancestors. And when they see their DNA mix and realize how colorful it is, they ask themselves, ‘Where the hell did that come from?'” He laughed. “And I say, ‘Well, your ancestor came from Sicily and there was a big seaport and weekend events… You just never know. The complexity of human passion and how it plays out in your own genome. You have 500 years of ancestry floating around in your genome, and it’s a wonderful thing to think about.”

This also contributes to the fact that “Finding Your Roots” addresses some issues that are quite relevant today.

“What’s your favorite subject?” Gates asked. “Your favorite subject is yourself. It’s a way to discover the layers of meaning within your personal identity. But our two recurring underlying political themes are, first, that at the genome level, we are 99.99% the same, despite our obvious differences. And second, that no matter what we look like or what our names are, we all descend from immigrants. Even our Native American sisters and brothers, their ancestors migrated across the Bering Strait 15,000 years ago. We truly are a nation of immigrants, and that makes us, in my opinion, the greatest country on earth. Those are the lessons we teach every week, and I believe that’s the reason for our popularity.

“Our country is experiencing such division and the rise of so many hateful feelings – anti-Semitism, anti-black racism, xenophobia in all areas, anti-immigrant sentiments – and ‘Finding Your Roots’ fights racism of all kinds, one family tree at a time.”

A version of this story first appeared in the Down to the Wire: Comedy issue of TheWrap awards magazine. Read more from the issue here.