Haplogroup J1, more fully Y DNA haplogroup J-M267, is a Y chromosome haplogroup found in the Middle East. This means it represents a group of descendants from a single common ancestor along the father's line. It carries a mutation on the Y chromosome known as M267. This type of mutation is called a SNP, or a single nucleotide polymorphism, which is a change in the chemicals at one position in a gene's DNA. Y chromosomes are passed down from father to son without changing, so an SNP like this shows common ancestry.