Haplogroup X originated in the western part of the Old World, and is not shared by most Mongoloids, with the exception of some Siberians and Native Americans. This study failed to discover its presence in South American Indians.
American Journal of Physical Anthropology (Early View)
Is haplogroup X present in extant South American Indians?
Cláudia L. Dornelles et al.
A total of 1,159 mitochondrial DNA samples from two Mongolian, two Siberian, and 25 South Native American populations was surveyed for the presence of the C16278T mutation, frequently found in haplogroup X. Material from 25 carriers of that mutation was then sequenced for the hypervariable segment I (HVS-I) control region, and those that still were not classifiable in classical Amerindian haplogroups were further studied. The tests involved all the control region, as well as the presence of characteristic mutations in seven coding fragments, totalling 5,760 base pairs. The results indicate that haplogroup X is not present in these samples.