Learn
Short, plain-language explanations for readers with no genetics background. Read these first and the rest of the site becomes far easier to interpret.
Foundations
01
A haplogroup is a large family of related genetic lineages that all descend from one ancestor who carried a particular set of mutations. Naming a haplogroup is a way of naming a branch on a family tree that is thousands of generations deep.
02
The Y chromosome passes almost unchanged from father to son. Because it skips recombination across most of its length, it preserves a clean record of one single ancestral line — a man's father's father's father, and so on.
03
A subclade is a smaller branch inside a haplogroup, defined by additional mutations that arose later. E1b1a1 is a subclade of E1b1a, which is a subclade of E1b, and so on down the tree.
04
Occasionally a copying error occurs when DNA is passed on. If that change is harmless it can be inherited indefinitely. Everyone who carries it descends from the man in whom it first appeared, so each stable mutation marks a new branch.
05
Researchers count the mutations that separate living men from a shared ancestor and divide by an estimated mutation rate. Different rates and calibration methods produce different answers, which is why this atlas presents ranges rather than fixed dates.
06
Sequencing DNA from ancient remains shows which lineages were actually present in a place at a given time, rather than inferring the past only from living populations. Findings such as the Shum Laka individuals in Cameroon have substantially revised earlier models.
07
Ethnicity is social, historical and cultural. A haplogroup is a genealogical branch. Members of one ethnic group typically carry several different haplogroups, and one haplogroup is usually found across many ethnic groups and languages.
08
Your Y-DNA line is a single thread among thousands of ancestral lines. Ten generations back you have over a thousand ancestors, and your Y chromosome comes from exactly one of them. It is informative, but it is a small slice of your ancestry.
Reading the atlas
Ranges, not dates. Prehistoric estimates carry wide uncertainty, and different studies disagree by thousands of years.
Frequencies, not definitions. "Frequently observed in" describes a sample of men, not the essence of a people.
Movement, not replacement. Later expansions rarely erased earlier populations; lineages overlap and persist side by side.
A living science. New sampling and ancient DNA regularly redraw parts of the tree, including its very root.
Honoring the Ancestors. Inspiring the Future.