Haplogroup R-Z18

Haplogroup R-Z18 is a haplogroup that includes all men who have the single nucleotide polymorphism (SNP) designated Z18 in their Y chromosome. Z18, also called S493, is defined to be mutation in which the nucleotide at position 14,991,735 along the Y chromosome has mutated from guanine (G) to adenine (A). Haplogroup R-Z18 includes all men who have a male-only line of descent from the first man to be conceived with the Z18 mutation.

R-Z18 is a subclade of haplogroup R-U106, which is one of the major haplogroups in Western Europe. Judging from the distribution of known carriers of Z18, the first carrier of Z18 likely lived in the Baltic basin in Northern Europe.