Linda Piekut, executive director of the Heritage Library on Hilton Head Island, shows an example of a DNA test package.

Stories passed down through the generations about your ethnicity might have you wondering about the accuracy of these shared tales.

AncestryDNA, 23andme and other companies that promote genetic ancestry or DNA testing might help you pinpoint facts about your ancestry and certain health risks. They might help you identify new relatives, especially if you’re adopted.

Some people might want to know why they have large noses, curly hair or other physical traits, said Brandon M. Welch, Ph.D., an assistant professor in the Biomedical Informatics Center at the Medical University of South Carolina.

“People are curious about where they came from,” said Welch, who has used DNA tests to uncover his own ethnicity. These tests can confirm or reject certain claims, he said.

Welch said he was told his paternal grandmother had some Native American ancestry. But DNA tests revealed he was 99.2 percent European and less than one percent North African. “I’m pretty much European,” he said. “There is no Native American blood in me.”

A DNA test will connect people with similar DNA markers and help genealogists with their family history research, said Linda Piekut, executive director of the Heritage Library on Hilton Head Island. “They love to find family members, and share stories and pictures,” she said.

The trend prompted the Heritage Library to offer classes so people could learn about different DNA tests and how to interpret results.

Consumers can order DNA test kits from various companies. The kits typically contain a tube for saliva or a cotton swab to collect a sample of cells from the inside surface of the cheek. The tubes are sealed and returned to the company for testing.

Beaufort resident Bradley Smith had two DNA tests performed so he could compare results and verify information he had researched for his family tree.

The testing companies have large databases so they can compare DNA samples from individuals and put them in groups of people with the similar genetic patterns or markers, Smith said. This helps them to pinpoint regions across the world where a person’s family might have come from.

AncestryDNA, for instance, touts a database of more than 5 million people who have taken its test. The results, according to its website, might include information about a person’s ethnicity across 26 regions and ethnicities and can identify potential relatives through DNA matching to others who have taken the AncestryDNA test.

“In my family, we knew there were Irish names, but we didn’t know how much Irish we were,” Smith said. DNA test results from Ancestry revealed that 48 to 52 percent of all people in Ireland carry the same genetic markers as Smith’s family. Smith said the results confirmed information that family members had shared with him.

As people dig into their family histories, Welch cautions people about using some DNA tests for health purposes. He said the Food and Drug Administration (FDA) recently cracked down on direct-to-consumer DNA tests for health, or tests that are marketed to consumers through various forms of advertisements.

“In order to have any genetic test for health, you have to have an order from a doctor. It’s largely because you have to know how to interpret the results,” Welch said.

Welch said the direct-to-consumer tests are good for curiosity-seekers. But, he cautioned, don’t use the tests if you’re not interested in finding out something astounding, “like, your dad isn’t your dad. Don’t expect life-changing results like being a descendent of a Cherokee Indian princess,” he said.

“You’re just as normal as the rest of us,” Welch said. “It’s cool to be linked to people.”

Carolyn Grant is an experienced journalist and freelance writer living on Hilton Head Island.