Between shooting the first two episodes of The Secret DNA of Us – a world-first show in which the residents of four Australian towns and suburbs are mass DNA-tested to find out more about where their family comes from – host Marc Fennell recorded his upcoming episode of
“It’s hard for me to untangle those experiences, because they are so related,” host Fennell says of exploring the unexpected twist and turns of his Indian-Irish background while surprising a raft of fellow Australians with their own backstories, which are often more complicated than they expect.

Marc Fennell in season 16 of Who Do You Think You Are? Australia.
“There’s a real duty of care in how you handle that, and I had a lot more empathy after shooting . You need to give a lot more space to people when you’re sitting down with a bunch of documents in front of them and be alive to the fact that what’s going to trigger an emotional reaction for them may not necessarily be what you think it’s going to be.”
He’s joined on The Secret DNA of Us by Wiradjuri and Greek STEM journalist Rae Johnston and ancestry expert Brad Argent. Together, they visit regional town Bairnsdale in East Gippsland and port city Geelong in Victoria, plus the inner-Sydney suburb of Surry Hills and the Central Tablelands outpost of Bathurst in NSW. In each location, they reveal the results from DNA-testing a bunch of local residents, discovering who’s related to who and the surprise ethnicities in their personal history.
Fennell views our overlapping family histories as a global saga, particularly in Australia, where so many of us were born overseas or have parents who were. And folks aren’t always as sure of their lineage as they think. One woman, who thought she was probably Scottish, maybe a bit Irish, winds up discovering 15 ethnicities in her family mix. “I joked at the time that she was officially the most SBS person in the room,” Fennell chuckles.
Along the way, the team debunks some tall tales passed down the ages – that families are related to queens or Elvis, the king of rock and roll. But they confirm quite a few more, or wilder twists thereof. “For every story we debunk, there are ones where the truth is 11 million times more interesting,” Fennell says.
... the reality has so many weird twists and turns it honestly blew my mind.
You can see his joy in every reveal on the show. “There’s a woman in Geelong… who’s never known who her father was, and the twists and turns in that reveal is next level. And there’s a man in Bathurst who has a family story that they’re related to an exiled French count, but the reality has so many weird twists and turns it honestly blew my mind.”
Fennell and co trace an indirect line from Punjabi queen Jindan Kaur and her son Maharaja Duleep Singh to Queen Victoria and on to Bairnsdale via an unexpected figure.
The Russian revolution brings exiles to Surry Hills via refugee camps, as the suburb thrums through successive waves of immigration that have shaped its unique character. Strangers discover they are related via the infamous underworld queen Kate Leigh, though Fennell cautions reading too much into rap sheets.
“I’ve spent a lot of time covering Irish and Scottish history and they pop up a lot in criminal records,” he notes. “But what people often don’t realise is, what are the circumstances around that? And in large part, structural poverty has been put in place.”
Even the hosts have something unexpected to learn. “I’m so grateful for the team, for Rae and Brad, because we bring really distinctive points of view to this history and our own bits of the story,” Fennell says. “There’s an amazing moment with Brad in the last episode where we realise he’s a bigger part of the show than he knows.”

Marc Fennell with ancestry expert Brad Argent (left) and journalist Rae Johnston.
Fennell’s enduring fascination with history, through a series of TV shows and podcasts, is more about solving mysteries. “I look for a small doorway into a big world,” he says. “Through the years of me covering technology and the years of me covering history, this is like the Venn diagram of how those things overlap.”
The Secret DNA of Us is a world-first show, combining DNA testing to unlock certain truths hidden in our bodies, then cross-referencing with official records. “The DNA [testing] is vitally important in opening it up, but after that, you have to go into the records and piece it together,” Fennell says. “But they record certain things and leave a lot out.”
As was made clear by Fennell’s stint on : “The birth and marriage records of my family call every woman a spinster, but I know for a fact that my grandmother was a bookkeeper,” he says. “She could do numbers like nobody’s business, so the records aren’t the full story. It always comes down to story.”
Numbers, records and a little bit of spit make for a winning combination. “When you use DNA testing en masse alongside the records, you can unravel the tapestry of Australia to tell the story of a nation. You and I are the latest chapter in a story that has been stretched for 1000 years, and it’s very humbling to realise that it connects to huge moments in history and foundational stories. You can’t help but have a bit of respect for the enormity of that.”
The Secret DNA of Us airs weekly from Thursday 17 April at 7.30pm on SBS with each episode then available to stream free on SBS On Demand.
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The Secret DNA of Us