Further comments on the characterization of founder Amerindian mitochondrial haplotypes

Context of maternal lineages in the Greater Southwest

We present mitochondrial haplogroup characterizations of the prehistoric Anasazi of the United States (US) Southwest. These data are part of a long-term project to characterize ancient Great Basin and US Southwest samples for mitochondrial DNA (mtDNA) diversity. Three restriction site polymorphisms (RSPs) and one length polymorphism identify four common Native American matrilines (A, B, C, and D). The Anasazi (n = 27) are shown to have a moderate frequency of haplogroup A (22%), a high frequency of haplogroup B (56%), and a low frequency of C (15%). Haplogroup D has not yet been detected among the Anasazi. In comparison to modern Native American groups from the US Southwest, the Anasazi are shown to have a distribution of haplogroups similar to the frequency pattern exhibited by modern Pueblo groups. A principal component analysis also clusters the Anasazi with some modern (Pueblo) Southwestern populations, and away from other modern (Athapaskan speaking) Southwestern populations. The Anasazi are also shown to have a significantly different distribution of the four haplogroups as compared to the eastern Great Basin Great Salt Lake Fremont (n = 32), although both groups cluster together in a principal component analysis. The context of our data suggests substantial stability within the US Southwest, even in the face of the serious cultural and biological disruption caused by colonization of the region by European settlers. We conclude that although sample numbers are fairly low, ancient DNA (aDNA) data are useful for assessing long-term populational affinities and for discerning regional population structure.

Implications of the distribution of Albumin Naskapi and Albumin Mexico for new world prehistory

The known distributions of two mutational variants of the albumin gene that are restricted to Mexico and/or North America, Albumin Mexico (AL*Mexico) and Albumin Naskapi (AL*Naskapi), were expanded by the electrophoretic analysis of sera collected from more than 3, 500 Native Americans representing several dozen tribal groups. With a few exceptions that could be due to recent, isolated cases of admixture, AL*Naskapi is limited to groups that speak Athapaskan and Algonquian, two widely distributed language families not thought to be related, and to several linguistically unrelated groups geographically proximate to its probable ancestral homeland. Similarly, AL*Mexico is limited to groups that speak Yuman or Uto-Aztecan, two language groups in the American Southwest and Baja California not thought to be closely related to each other, and to several linguistically unrelated groups throughout Mexico. The simultaneous consideration of genetic, historical, linguistic, and archaeological evidence suggests that AL*Naskapi probably originated on the northwestern coast of North America, perhaps in some group ancestral to both Athapaskans and Algonquians, and then spread by migration and admixture to contiguous unrelated, or distantly related, tribal groups. AL*Mexico probably originated in Mexico before 3,000 years BP then spread northward along the Tepiman corridor together with cultural influences to several unrelated groups that participated in the Hohokam culture.

Characterization of ancestral and derived Y-chromosome haplotypes of New World native populations

We analyze the allelic polymorphisms in seven Y-specific microsatellite loci and a Y-specific alphoid system with 27 variants (alphah I-XXVII), in a total of 89 Y chromosomes carrying the DYS199T allele and belonging to populations representing Amerindian and Na-Dene linguistic groups. Since there are no indications of recurrence for the DYS199C-->T transition, it is assumed that all DYS199T haplotypes derive from a single individual in whom the C-->T mutation occurred for the first time. We identified both the ancestral founder haplotype, 0A, of the DYS199T lineage and seven derived haplogroups diverging from the ancestral one by one to seven mutational steps. The 0A haplotype (5.7% of Native American chromosomes) had the following constitution: DYS199T, alphah II, DYS19/13, DYS389a/10, DYS389b/27, DYS390/24, DYS391/10, DYS392/14, and DYS393/13 (microsatellite alleles are indicated as number of repeats). We analyzed the Y-specific microsatellite mutation rate in 1,743 father-son transmissions, and we pooled our data with data in the literature, to obtain an average mutation rate of.0012. We estimated that the 0A haplotype has an average age of 22,770 years (minimum 13,500 years, maximum 58,700 years). Since the DYS199T allele is found with high frequency in Native American chromosomes, we propose that 0A is one of the most prevalent founder paternal lineages of New World aborigines.

mtDNA haplogroup X: An ancient link between Europe/Western Asia and North America?

On the basis of comprehensive RFLP analysis, it has been inferred that approximately 97% of Native American mtDNAs belong to one of four major founding mtDNA lineages, designated haplogroups "A"-"D." It has been proposed that a fifth mtDNA haplogroup (haplogroup X) represents a minor founding lineage in Native Americans. Unlike haplogroups A-D, haplogroup X is also found at low frequencies in modern European populations. To investigate the origins, diversity, and continental relationships of this haplogroup, we performed mtDNA high-resolution RFLP and complete control region (CR) sequence analysis on 22 putative Native American haplogroup X and 14 putative European haplogroup X mtDNAs. The results identified a consensus haplogroup X motif that characterizes our European and Native American samples. Among Native Americans, haplogroup X appears to be essentially restricted to northern Amerindian groups, including the Ojibwa, the Nuu-Chah-Nulth, the Sioux, and the Yakima, although we also observed this haplogroup in the Na-Dene-speaking Navajo. Median network analysis indicated that European and Native American haplogroup X mtDNAs, although distinct, nevertheless are distantly related to each other. Time estimates for the arrival of X in North America are 12,000-36,000 years ago, depending on the number of assumed founders, thus supporting the conclusion that the peoples harboring haplogroup X were among the original founders of Native American populations. To date, haplogroup X has not been unambiguously identified in Asia, raising the possibility that some Native American founders were of Caucasian ancestry.