The significance isn’t lost on the couple. Years before she became the first Black woman on the Supreme Court, Jackson pointed to the stark differences in her and her husband’s backgrounds during a 2017 speech at the University of Georgia. He was pre-med, she studied government; he was a Harvard legacy several times over, she was only the second generation in her family to go to college. He was a “quintessential ‘Boston Brahmin,’ ” she said, while her lineage led back to slavery.

“We were an unlikely pair in many respects,” Jackson told the audience. “But somehow we found each other.”

Their family demonstrates “the richness of ethnic identity in America,” said Henry Louis Gates Jr., who leads Harvard’s Hutchins Center for African & African American Research and hosts the PBS genealogy show “Finding Your Roots.”

It is also a reminder of which stories this country has celebrated, and which it has chosen to forget.

Their achievements have not as often been described, “but I’m sure that her African American ancestors were quite distinguished, too,” Gates said. “A person like that didn’t come from nowhere.”

In February, when President Biden nominated Jackson to the Supreme Court, a group of local genealogists set out to find where, and who, she came from. It started as an informal project for researchers at the Boston-based nonprofit American Ancestors, also known as the New England Historic Genealogical Society, who tracked both sides of the Jackson family. They wanted to see how far they could get.

From the first, their efforts presented a study in contrasts. Patrick Jackson’s ancestry was relatively easy; one of the…