Autosomal vs Y-DNA vs mtDNA: Which Test Type You Actually Need

The DNA test you buy for $39 on a Black Friday sale is almost always an autosomal test. It is one of three kinds of consumer DNA test, and it answers one specific kind of ancestry question. The other two test types, Y-DNA and mtDNA, are sold by far fewer companies and answer very different questions. Buying the wrong type wastes money, so it is worth understanding which one maps to what you actually want to learn.

Autosomal DNA: the last few generations

Autosomal DNA is the 22 pairs of non-sex chromosomes you inherit from both parents. Each parent contributes half, each grandparent roughly a quarter, each great-grandparent roughly an eighth, and so on. By around the seventh generation back, you stop reliably inheriting measurable DNA from every ancestor, which means autosomal tests give clear answers for the last five to seven generations and then fade.

This is the test type used by AncestryDNA, 23andMe, MyHeritage, FamilyTreeDNA Family Finder, and Living DNA. It is what powers ethnicity estimates, cousin matching, and “find your fourth cousin in Idaho” features. If you want to find living relatives, build a modern family tree, or get a regional ancestry estimate, autosomal is the right test.

For privacy considerations specific to 23andMe given its 2025 bankruptcy and TTAM transition, see our genetic data privacy guide.

Y-DNA: the strictly paternal line

The Y chromosome passes from father to son largely unchanged. A man inherits his Y-DNA from his father, who got it from his father, all the way back. This means a Y-DNA test traces one specific line through your tree: father’s father’s father, indefinitely. Women cannot take a Y-DNA test because they do not have a Y chromosome; they would need a male paternal-line relative (father, brother, paternal uncle, paternal grandfather) to test on their behalf.

Y-DNA does not fade after seven generations like autosomal DNA. Mutations accumulate slowly along the line, and matching is based on shared mutation patterns. This lets Y-DNA testing reach back hundreds or thousands of years along that one line. It is the standard tool for surname studies, deep paternal heritage research, and connecting to ancient population groups through Y haplogroups.

FamilyTreeDNA is the only major consumer company that currently offers dedicated Y-DNA tests. Its Big Y-700 product, priced around $449 and frequently discounted as of early 2026, is the most detailed consumer Y-DNA test on the market.

mtDNA: the strictly maternal line

Mitochondrial DNA is the small genome inside the mitochondria in your cells. You inherit it from your mother, who inherited it from her mother, indefinitely back the strict maternal line. Both men and women can take an mtDNA test; both inherit mtDNA from their mothers. Only women pass it on.

Like Y-DNA, mtDNA does not fade. It mutates slowly and is used to assign maternal haplogroups that connect modern people to ancient population migrations. It is most useful for deep maternal-line research and for proving or disproving specific maternal-line relationships.

FamilyTreeDNA’s mtFull Sequence is the standard consumer mtDNA test. Living DNA reports an mtDNA haplogroup as part of its main kit, but for serious maternal-line research the dedicated test is the standard tool.

How they compare

Test type	Inheritance	Time depth	Who can take it	Where to buy
Autosomal	Both parents	Last 5 to 7 generations	Anyone	Ancestry, 23andMe, MyHeritage, FTDNA, Living DNA
Y-DNA	Father to son only	Hundreds to thousands of years, paternal line only	Males only	FamilyTreeDNA
mtDNA	Mother to all children	Hundreds to thousands of years, maternal line only	Anyone	FamilyTreeDNA

Which one should you buy first

For most people, the answer is autosomal. It is cheaper, the matching is useful immediately, and it covers the time period most family historians care about. Buy a Y-DNA test if you are researching a specific paternal surname line or want to know your deep paternal heritage. Buy an mtDNA test if you want the same for your strict maternal line.

For the broader picture, see our guide to choosing a DNA test or the explainer on how DNA tests work.