By Richard Allen Greene
BBC News, Washington
Denise Oliver-Velez was, she says, "a nosy child".
When her mother showed her family pictures, she always wanted to know who everyone was - not simply that they were "cousins", but exactly how they were related to her.
Her father, on the other hand, had little or no contact with his extended family.
Denise Oliver-Velez's grandparents were a mixed-race couple
As Denise grew older, she learned the reason: she is an African-American, but her grandmother Mabel - her father's mother - was white.
Mabel Bodine had married a black man - an illegal act in her home state of Kansas in 1915 - prompting almost her entire family to cut off contact with her and forcing her to flee the state. The wedding took place in Wisconsin.
Denise's interest in her family history never waned, and eight or nine years ago, she says, she began tracing her genealogy in earnest.
She has become so expert at it that she now helps newcomers to AfriGeneas, a website devoted to helping African-Americans find their roots - an increasingly popular hobby for black people.
"Genealogy essentially used to be the purview of people whose ancestors swam over before the Mayflower," she says, joking about people's efforts to prove their family had been in America since its founding days in order to join exclusive societies.
Myths and barriers
Now, websites like AfriGeneas and Ancestry.com - and the digitalisation of records once confined to dusty books - have made roots research easier for African-Americans.
But there are still barriers, experts say.
One hurdle to overcome is the belief that there are no records to be found, says Megan Smolenyak, who made what is probably the most startling American genealogical discovery of the year.
Ms Smolenyak, the chief family historian at Ancestry.com, found that the ancestors of African-American activist Al Sharpton had been owned by the ancestors of the late Senator Strom Thurmond, the most powerful segregationist of his day.
She says it is a "myth" that African-Americans cannot trace their family trees.
"It does get harder once you get back into slavery," she admits, but even there, records do exist.
"Sad to say, human beings were treated like property, so you are looking for estates, wills, at least the first names of your ancestors.
"You have to do double work - you have to find out who owns your family, and then you have to research the paper trail of the owning family," she says.
To go further back in history - linking families to their origins in Africa - DNA research is usually required, Ms Smolenyak says.
That is an increasingly popular option, according to Gina Paige, the president of African Ancestry, which does DNA research.
"We have traced the ancestry of 8,000 people since 2003," she says, and her company is only one of a growing number that provide the service.
DNA testing is "very popular and it is growing now that people know it is possible," she says.
Her company charges from $350 to $600 (£180 to £300) for the service.
TV host Oprah Winfrey may have helped spark interest in DNA testing when she announced in 2005 she had found she was a Zulu.
Some experts questioned her assertion, saying genetic testing was not precise enough to identify tribes or linguistic groups - and pointing out that most American slaves come from west Africa, not the south of the continent.
However imprecise some might see the process, tracing roots back to Africa "answers a fundamental question that most people have, which is: 'Where am I from?'," Ms Paige says.
"African-Americans are the only people in the country who cannot point to a country of origin. It helps them to develop a sense of place and a sense of belonging," she adds.
DNA testing also enables them to bypass a problem that sometimes hinders African-Americans doing research in the traditional way, Denise Oliver-Velez says. She says that some white people do not want to face up to the findings of historical inquiry.
"Some people are offended if you contact them and say: 'Your great-grandparents owned my great-grandparents.'
"There are a lot of people who, to this day, don't want to connect their family to that particular history, and they don't even answer when you contact them," she says.
That discomfort once meant it was common for families to erase indications their ancestors had been slave-owners.
"They would publish wills but they would edit out: 'I gave Susie to my daughter as a wedding present.' People were embarrassed by it," Denise says.
So many African-Americans get the cold shoulder when trying to find out about their slave ancestors that some hide the fact they are black when first making contact with the slave-owners' descendants.
"They hope that someone will think they are part of the family," the researcher says.
She herself has been lucky enough to have the opposite experience two different times.
The first was when she tracked down Carole Palmer, whose ancestors, she suspected, had freed her great-grandfather Presley Roberts.
She was right, and not only had they freed him, they helped him buy land in Virginia which Denise owns to this day.
"It was heart-warming" to be contacted by Denise, Carole Palmer says - if not exactly surprising.
The Rev John Marks, the ancestor in question, had been a minister known for being a "very good man", and it was one of his daughters who freed Presley Roberts.
"I was totally unaware of that," Carole says, or that her ancestors had even held slaves.
Marks's daughter apparently married a man who owned slaves. Her husband died before she did and she freed the slaves in her will when she died, Carole learned.
Her family tree website now links to Denise's, which Denise calls "incredible" given the hostility African-American genealogists sometimes encounter.
Denise was also on the receiving end of a surprise - when a descendant of her white grandmother's family found her website.
"He clicked on a few more links and found some black folk and practically fell off his chair," she says. He then went to his parents and asked them why he had never heard of the relative who married a black man.
The cousin, Joe Bodine, went to meet Denise and sent her photos of family graves in Kansas.
"As a result of that decision, I have been reunited with my grandmother's family - people my father never got to meet."
There is a lesson in all this, Denise feels.
"When you start digging, you never know what you are going to turn up. African-Americans find native Americans in their family trees.
"People classified as white find they have African-American ancestors. Some accept it. Some don't.
"I warn people: 'Be prepared to accept whatever you find. Keep following the thread. Your ancestry is your ancestry. American history is American history, no matter what your colour.'"