“My mother did not approve of Indians, and she insisted that my father was not an Indian,” said Mapes, 77, of Catalina, Ariz. “In those days, it was not a plus to be an Indian, not at all. She said that Granny, my father’s mother, was just making it up and she did not believe it.”

Mapes, a mother of four who volunteers in a clothing bank, is a second cousin to US Senate candidate Elizabeth Warren. The two women, who have never met, share more DNA than most second cousins: Not only were their grandmothers sisters, their grandfathers were brothers. Those brothers — a team of carpenters named Harry and Everett Reed who plied their trade in the Indian Territory that would become the state of Oklahoma — are believed by some family members to have roots in the Delaware tribe. Mapes, who said she was unaware of her cousin’s candidacy until contacted by a reporter, said she does not doubt her heritage.

“I think you are what you are,” said Mapes. “And part of us is Indian.”

Questions about Warren’s roots have continued to shadow her candidacy since the matter erupted in a political firestorm in April. Warren acknowledged that she had identified herself as a minority in a legal directory for nearly a decade, and she was listed as a Native American in federal forms filed by the law schools at Harvard University and University of Pennsylvania where she worked. Warren has never fully explained her assertion of Native American ancestry, and her Republican opponents continue to brand her a liar. Officials from both schools have said that her assertion of ancestry was not a factor in her hiring.

Warren’s extended family has mixed opinions on the Native American question. The stories shared by Mapes, as well as Warren’s brothers and a number of her cousins, echo Warren’s assertion. But other cousins, some of whom also do not know Warren, say they know nothing of Native American blood in the family. According to one family biography, on file at the California State University at Fullerton, one of Warren’s relatives once shot at an Indian.

Months after the political flare-up, Warren and some of her family members remain unwilling to provide details on the subject. In a lengthy interview, Warren referred to stories about her roots that she says were frequently told at family gatherings in her native Oklahoma, but declined to share virtually any of them. “I knew it was part of our family,” Warren said. “It was part of what we talked about. . . . It was just part of who we were.”

Warren’s family, including cousin Mapes, have no documentation of Native American affiliation, nor is there evidence that they are listed on any official tribal roll. While Senator Scott Brown, Warren’s opponent, has used this to question her truthfulness, many who assert such heritage are unable to document it, according to several scholars. During the late 1800s and early 1900s, many Native Americans did not join tribal rolls for a host of complex reasons, including residency requirements, fear of discrimination, and opposition to land allotment policies.

In the absence of documentation, the family’s link to any Native American tribe is a matter of narrative inheritance or folklore, as Warren puts it. Even if Warren has some degree of Native American blood, it is unclear if it would meet conventional standards of what constitutes a minority.

Warren’s reluctance to talk about it, or to explore possible documentation, reflects the complex questions about biography and childhood memory that have percolated through the bitterly fought race for the Senate seat. Brown has also been said by some members of his family to have embroidered his painful past. One cousin, for example, says he exaggerated episodes of deprivation in his childhood.