In human genetics, Haplogroup Q3 (M242) is a Y-chromosome haplogroup. This haplogroup contains the patrilineal ancestors of almost all of the indigenous peoples of the Americas.
Haplogroup Q3 is a descendant of haplogroup Q (M242). Since the parent Q (M242) appears in both Asia and the Americas, while Q3 (M3) appears only in the Americas, it is believed that the mutation M3 occurred in North America after migration across the Bering Strait had ceased.
The only indigenous peoples of the Americas who are not of haplotype Q3 (M3) are those of haplogroup C (M130), today's Na-Dené speakers, who arrived 6,000-8,000 years ago and settled on the coast of modern British Columbia.