Famed Harvard University Professor Henry Louis 'Skip' Gates Jr. got a major surprise when he started researching his own ancestry - in his paternal line he discovered he's as Irish as Irish can be.

Now Gates has set about solving another mystery - just who exactly is his great-great grandfather? It is likely he was a slave owner of Irish heritage.

Gates made world headlines in 2009 when he accused an Irish American cop James Crowley of racism in 2009 after Crowley arrested him for trying to break into his own apartment. Eventually President Obama became involved and met the two men for a famous ‘beer summit’ where they became friends.

The Gates family history can be traced back to Jane Gates, a slave who was born in 1819 and had five children, taking the name and identity of their father with her to the grave.

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'All Jane told the kids was that they all had the same father,' Gates said in a report in the Boston Herald. 'I have a picture of Jane Gates and her sons and they all look white, including my great-grandfather, Edward Gates, who was born December 1857 in Maryland. I’m looking to find my great-great-grandfather and I hope to find him using DNA analysis.'

After conducting his own research, Gates now believes that an Irish descendant of Niall of Nine Hostages fathered all five of Jane’s children.

"Hoping to help solve this troubling mystery. Family legend had it that the father of Jane’s children was a slave owner outside of Cumberland, Maryland, named Samuel Brady. I had my y-DNA tested. The results astonished everyone, including me: my y-DNA haplotype is R1b1b2ala2f2, also known as 'the Ui Neil Haplotype.' At least 8 percent of all the men in Ireland share this same haplotype, and all of us descend from one man, a king named Niall of the Nine Hostages, who lived in Ireland around 500 A.D."

The y-DNA was passed down to Gates' grandfather Edward Lawrence Gates and Gates inherited it from own his father, Henry Louis Gates Sr. 'On my paternal line, in other words, we are as Irish as Irish can get,' writes Gates.

But the Gates family later found out that Brady was not in fact their great-great-grandfather, so now the search is on. Scientists can trace a family's origins by analyzing DNA obtained from saliva on the mother’s mother’s mother’s line, and on the man’s father’s father’s father’s line.

That's why residents of Gates ancestral home of Allegany County, Maryland, who are of Irish descent, have been asked to send in a DNA sample to see if they are related to Gates. Those with a DNA match may be featured in the new PBS miniseries 'Finding Your Roots with Henry Louis Gates,' which will premiere March 25 at 8 p.m.

"I don’t think you can know who you are without looking into your ancestry. I think it’s empowering to learn where you came from," said Gates.