So many different types of genetic genealogy tests and analyses are out there, it can be hard to decide which would best suit your needs. Here’s an overview of available tests; see our list of testing companies to see which types of tests they offer. If you’re confused about which test to order, call the company and let them know what you’d like to learn from taking a genetic genealogy test.
Because surnames, like Y-chromosomes, are passed from father to son, a Y-DNA test can be a useful tool in determining whether families with the same last name are related—but it can’t pinpoint the common ancestor. Information from a Y-DNA test relates to your paternal line, with no influence of any females along that line, so it won’t help if you want to know whether you’re related to someone through, say, your father’s mother. This test also can be used to determine a haplogroup (see below) for your male line. Since only males receive the Y-chromosome, only men can take this test. Females who want to find out more about their paternal line need to have a male relative from that line tested.
Somewhat like the feminine version (with a few differences) of the Y-DNA test, a mitochondrial (mt) DNA test will tell you about your female line with no influence of any males along that line. Because mtDNA doesn’t mutate much over time, this test is best for telling you about your “deep” maternal-line ancestry—you’ll be assigned to a haplogroup, often described as your branch of the world family tree. If your mtDNA test results match someone else’s, there’s a good bet you’re related, but it’ll be hard to tell how long ago your common ancestor lived. MtDNA is passed from mother to both sons and daughters, so men and women can take this test.
To discover your ethnic ancestry, you’ll need to take a standard Y-DNA or mtDNA test through a lab that can provide additional analysis comparing your results to those typical of certain ethnicities. You’ll have to be mindful about choosing the correct family member to test. If you think your mother’s father was American Indian, for example, don’t test yourself—your mother didn’t get Y-DNA or mtDNA from him, and neither did you. Instead, have her brother take a Y-DNA test.
Also called admixture tests, These tests examine autosomal DNA markers to determine your genetic heritage among anthropological groups such as Native American, Indo-European, East Asian and Sub-Saharan African. Additional testing can further subdivide certain groups. These tests are somewhat controversial because results can be inconclusive, and the East Asian and Native American groups can be hard to differentiate.
Autosomal or Short Tandem Repeat (STR)
The best way to confirm if you’re related to a living person is with an STR test. It can determine what relationship (if any), such as parent and child, sibling or cousin, exists between two individuals. Both individuals must provide a DNA sample.