Founding Haplogroups Research Articles

The maternal genetic history of tribal populations of Chhattisgarh, India

The central region of India boasts a rich tribal heritage and the highest number of tribal populations in the country. Analysing the genetic history of this population can offer valuable insights into various demographic processes that shaped the gene pool of present-day settlers of this region. In this study, we utilize a recently validated Next-generation sequencing (NGS) technique to sequence 24 tribal mitogenomes from the Chhattisgarh population for genetic ancestry and forensic analysis. The identified ancient haplogroups in this population can be traced back to the pre-Last Glacial Maximum (LGM) period. Our Bayesian analysis provides evidence for maternal ancestral expansion following the earliest Out-of-Africa migration, followed by a prolonged steady phase. We identified three basal founding haplogroups, M2, R5, and U2 in the Chhattisgarh region that diversified during the Neolithic period. Indistinct distribution pattern of these haplogroups among tribes and castes suggests that the maternal ancestry of Chhattisgarh population predates any kind of social stratification that exists today in the Indian subcontinent. Furthermore, our analysis suggests that this region remained unaffected by the Last Glacial Maximum. The forensic analysis of the mitogenomes demonstrates a high power of discrimination (0.9256) within the Chhattisgarh population, thus supporting the applicability of mitogenome NGS technology in forensic contexts.

Ancient mitogenomes from the Southern Pampas of Argentina reflect local differentiation and limited extra-regional linkages after rapid initial colonization.

This study aims to contribute to the recovery of Indigenous evolutionary history in the Southern Pampas region of Argentina through an analysis of ancient complete mitochondrial genomes. We generated DNA data for nine complete mitogenomes from the Southern Pampas, dated to between 2531 and 723 cal BP. In combination with previously published ancient mitogenomes from the region and from throughout South America, we documented instances of extra-regional lineage-sharing, and estimated coalescent ages for local lineages using a Bayesian method with tip calibrations in a phylogenetic analysis. We identified a novel mitochondrial haplogroup, B2b16, and two recently defined haplogroups, A2ay and B2ak1, as well as three local haplotypes within founder haplogroups C1b and C1d. We detected lineage-sharing with ancient and contemporary individuals from Central Argentina, but not with ancient or contemporary samples from North Patagonian or Littoral regions of Argentina, despite archeological evidence of cultural interactions with the latter regions. The estimated coalescent age of these shared lineages is ~10,000 years BP. The history of the human populations in the Southern Pampas is temporally deep, exhibiting long-term continuity of mitogenome lineages. Additionally, the identification of highly localized mtDNA clades accords with a model of relatively rapid initial colonization of South America by Indigenous communities, followed by more local patterns of limited gene flow and genetic drift in various South American regions, including the Pampas.

Overview of the Americas' First Peopling from a Patrilineal Perspective: New Evidence from the Southern Continent.

Uniparental genetic systems are unique sex indicators and complement the study of autosomal diversity by providing landmarks of human migrations that repeatedly shaped the structure of extant populations. Our knowledge of the variation of the male-specific region of the Y chromosome in Native Americans is still rather scarce and scattered, but by merging sequence information from modern and ancient individuals, we here provide a comprehensive and updated phylogeny of the distinctive Native American branches of haplogroups C and Q. Our analyses confirm C-MPB373, C-P39, Q-Z780, Q-M848, and Q-Y4276 as the main founding haplogroups and identify traces of unsuccessful (pre-Q-F1096) or extinct (C-L1373*, Q-YP4010*) Y-chromosome lineages, indicating that haplogroup diversity of the founder populations that first entered the Americas was greater than that observed in the Indigenous component of modern populations. In addition, through a diachronic and phylogeographic dissection of newly identified Q-M848 branches, we provide the first Y-chromosome insights into the early peopling of the South American hinterland (Q-BY104773 and Q-BY15730) and on overlying inland migrations (Q-BY139813).

Continental Origin for Q Haplogroup Patrilineages in Argentina and Paraguay.

Haplogroup Q originated in Eurasia around 30,000 years ago. It is present in Y-chromosomes from Asia and Europe at rather low frequencies. Since America is undoubtedly one of the continents where this haplogroup is highly represented, it has been defined as one of the founding haplogroups. Its M3 clade has been early described as the most frequent, with pan-American representation. However, it was also possible to find several other haplogroup Q clades at low frequencies. Numerous mutations have been described for haplogroup Q, allowing analysis of its variability and assignment of its geographic origin. We have analyzed 442 samples of unrelated men from Argentina and Paraguay belonging to haplogroup Q; here we report specifically on 27 Q (xM3) lineages. We tested 3 single-nucleotide polymorphisms (SNPs) by amplified product-length polymorphism (APLP) analysis, 3 SNPs for restriction fragment length polymorphism (RFLP) analysis, 15 SNPs by Sanger sequencing, and 17 short tandem repeats (STRs). Our approach allowed us to identify five subhaplogroups. Q-M3 and Q-CTS2730/Z780 are undoubtedly autochthonous lineages and represent the most frequent subhaplogroups, with significant representation in self-defined aboriginal populations, and their autochthonous status has been previously described. The aim of present work was to identify the continental origin of the remaining Q lineages. Thus, we analyzed the STR haplotypes for the samples and compared them with haplotypes described by other authors for the rest of the world. Even when haplogroup Q lineages have been extensively studied in America, some of them could have their origin in post-Columbian human migration from Europe and Middle East.

New Evidence of Ancient Mitochondrial DNA of the Southern Andes (Calchaquí Valleys, Northwest Argentina, 3,600–1,900 Years before Present)

Genetic studies on pre-Hispanic populations of the Southern Andes have been increasing steadily in the last decade. Nevertheless, ancient DNA characterization of Formative Period archaeological human remains is particularly scant, especially for Northwest Argentina. To expand current information on genetic characterization of the first agricultural communities of the southern Calchaquí Valleys, we present and discuss the first mitochondrial ancient DNA information obtained on samples dated to ca. 3,600-1,900 years before present from the Cajón Valley, Catamarca Province. Reproducible mtDNA hypervariable region 1 (HVR-1) sequences were obtained in seven individuals. Mitochondrial HVR-1 haplotypes were assigned to three of the four founding haplogroups, D1 (57.1%), C1 (28.5%), and B2 (14.2%), with absence of A2. Our results show that the Cajón Valley sample, with predominance of D1 and C1, differs from that commonly observed in ancient and modern Andean populations, which usually show a high prevalence of haplogroup B2. The fact that the Cajón Valley and Pampa Grande (Salta Province, Argentina) share a prevalence of haplogroup D1 could provide additional evidence to support possible genetic affinities between the valleys and the eastern sub-Andean region during the Formative Period in Northwest Argentina, expanding the archaeological evidence of contact between both populations. Future complete mitogenomic analysis will provide substantial information to formulate new hypotheses about the origins and phylogenetic relationships between the individuals of the Cajón Valley and other groups from the Andes, Gran Chaco, and the Amazon.

A biogeographic perspective on early human colonization of the Tibetan Plateau

Whence came the early human colonizers of the Tibetan Plateau? Recent genomic research of modern Tibetan gene pool diversity provides evidence of numerous different founding haplogroups among populations. Age estimates suggest that much of the Tibetan gene pool is the product of Holocene migration and admixture, but at least one distinct ancestral haplotype may pre-date the last glacial maximum. Key genes conferring high-altitude adaptation to Tibetan populations suggest that those populations diverged from Han Chinese ancestors between ~8–18calka BP. Diverse Upper Paleolithic technological packages existed in different regions around the margins of the Plateau that could have been carried up by potential early colonizers. However, archeological evidence of early (pre-Neolithic) occupation on the Plateau itself is remarkably uniform, consisting of small short-term camps with a mixed lithic technology featuring simple flakes and shatter, microblades and microcores, larger blades or bladelets, discoidal tablet cores, and occasional bipolar pebble cores; well-dated sites are all post-glacial in age. A simple biogeographic model, the “up from the north” hypothesis, asserts that human groups best suited to colonizing the harsh alpine Plateau environments would have been those adapted to life typical of higher latitudes, and those advantaged northern-latitude colonizers routinely carried microlithic technology with them in hunting the same Palearctic steppe fauna found on the Plateau. The archeological record of early colonizers on the Plateau should therefore be dominated by the north Asian epi-Paleolithic technological package in which microblades were a key component. Complications to this simple model, and possible scenarios addressing the disparity between the evidence from historical genetics and the archeological record, are considered.

A South American Prehistoric Mitogenome: Context, Continuity, and the Origin of Haplogroup C1d.

Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder haplogroups peopled the Americas. Subhaplogroup C1d3 was defined based on the mitogenome of a living individual from Uruguay that carried a lineage previously identified in hypervariable region I sequences from ancient and modern Uruguayan individuals. When complete mitogenomes were studied, additional substitutions were found in the coding region of the mitochondrial genome. Using a complete ancient mitogenome and three modern mitogenomes, we aim to clarify the ancestral state of subhaplogroup C1d3 and to better understand the peopling of the region of the Río de la Plata basin, as well as of the builders of the mounds from which the ancient individuals were recovered. The ancient mitogenome, belonging to a female dated to 1,610±46 years before present, was identical to the mitogenome of one of the modern individuals. All individuals share the mutations defining subhaplogroup C1d3. We estimated an age of 8,974 (5,748–12,261) years for the most recent common ancestor of C1d3, in agreement with the initial peopling of the geographic region. No individuals belonging to the defined lineage were found outside of Uruguay, which raises questions regarding the mobility of the prehistoric inhabitants of the country. Moreover, the present study shows the continuity of Native lineages over at least 6,000 years.

A recent bottleneck of Y chromosome diversity coincides with a global change in culture.

It is commonly thought that human genetic diversity in non-African populations was shaped primarily by an out-of-Africa dispersal 50–100 thousand yr ago (kya). Here, we present a study of 456 geographically diverse high-coverage Y chromosome sequences, including 299 newly reported samples. Applying ancient DNA calibration, we date the Y-chromosomal most recent common ancestor (MRCA) in Africa at 254 (95% CI 192–307) kya and detect a cluster of major non-African founder haplogroups in a narrow time interval at 47–52 kya, consistent with a rapid initial colonization model of Eurasia and Oceania after the out-of-Africa bottleneck. In contrast to demographic reconstructions based on mtDNA, we infer a second strong bottleneck in Y-chromosome lineages dating to the last 10 ky. We hypothesize that this bottleneck is caused by cultural changes affecting variance of reproductive success among males.

Identification of Whole Mitochondrial Genomes from Venezuela and Implications on Regional Phylogenies in South America.

Recent studies have expanded and refined the founding haplogroups of the Americas using whole mitochondrial (mtDNA) genome analysis. In addition to pan-American lineages, specific variants have been identified in a number of studies that show higher frequencies in restricted geographical areas. To further characterize Native American maternal lineages and specifically examine local patterns within South America, we analyzed 12 maternally unrelated Yekuana whole mtDNA genomes from one village (Sharamaña) that include the four major Native American haplogroups A2, B2, C1, and D1. Based on our results, we propose a reconfiguration of one subhaplogroup A2 (A2aa) that is specific to South America and identify other singleton branches across the four haplogroups. Furthermore, we show nucleotide diversity values that increase from north to south for haplogroups C1 and D1. The results from our work add to the growing mitogenomic data that highlight local phylogenies and support the rapid genetic differentiation of South American populations, which has been correlated with the linguistic diversity in the region by previous studies.

The mitochondrial DNA history of a former native American village in northern Uruguay.

In 1828, between 8,000 and 15,000 Indians from the Jesuit Missions were brought to Uruguay. There, they were settled in a village, presently named Bella Unión, in the northwest corner of the country. According to historic sources, the Indians abandoned the settlement shortly thereafter, with the village subsequently repopulated by "criollos" and immigrants from abroad. As a first approach to reconstruct the genetic history of the population, data about the living population genetic structure will be used. Based on the analysis of the maternal lineages of the inhabitants of Bella Unión, and of those from two nearby villages, we expect to partially answer what happened with the first and subsequent inhabitants. We analyzed the maternal lineages of the present inhabitants of Bella Unión and neighboring localities through the sequencing of the mitochondrial DNA control region. A total of 64.3%, 5.7%, and 30% of the mtDNAs were of Native, African, and West Eurasian origin, respectively. These figures are quite similar to that of the population of Tacuarembó, which is located in northeastern Uruguay. The four main Native American founding haplogroups were detected, with B2 being the most frequent, while some rare subhaplogroups (B2h, C1b2, D1f1) were also found. When compared with other Native American sequences, near- matches most consistently pointed to an Amazonian Indian origin which, when considered with historical evidence, suggested a probable Guaraní-Missionary-related origin. The data support the existence of a relationship between the historic and present inhabitants of the extreme northwest Uruguay, with a strong contribution of Native Americans to the mitochondrial DNA diversity observed there.

Mitochondrial DNA variability among six South American Amerindian villages from the Pano linguistic group.

Although scattered throughout a large geographic area, the members of the Pano linguistic group present strong ethnic, linguistic, and cultural homogeneity, a feature that causes them to be considered components of a same "Pano" tribe. Nevertheless, the genetic homogeneity between Pano villages has not yet been examined. To study the genetic structure of the Pano linguistic group, four major Native American mitochondrial DNA (mtDNA) founder haplogroups were analyzed in 77 Amerindians from six villages of four Pano tribes (Katukina, Kaxináwa, Marúbo, and Yaminawa) located in the Brazilian Amazon. The central position of these tribes in the continent makes them relevant for attempts to reconstruct population movements in South America. Except for a single individual that presented an African haplogroup L, all remaining individuals presented one of the four Native American haplogroups. Significant heterogeneity was observed across the six Pano villages. Although Amerindian populations are usually characterized by considerable interpopulational diversity, the high heterogeneity level observed is unexpected if the strong ethnic, linguistic, and cultural homogeneity of the Pano linguistic group is taken into account. The present findings indicate that the ethnic, linguistic, and cultural homogeneity does not imply genetic homogeneity. Even though the genetic heterogeneity uncovered may be a female-specific process, the most probable explanation for that is the joint action of isolation and genetic drift as major factors influencing the genetic structure of the Pano linguistic group.

Mitochondrial DNA Variability among Six South American Amerindian Villages from the Pano Linguistic Group

Mitochondrial DNA Variability among Six South American Amerindian Villages from the Pano Linguistic Group Celso T. Mendes-Junior and Aguinaldo L. Simoes abstract Although scattered throughout a large geographic area, the members of the Pano linguistic group present strong ethnic, linguistic, and cultural homogeneity, a feature that causes them to be considered components of a same “Pano” tribe. Nevertheless, the genetic homogeneity between Pano villages has not yet been examined. To study the genetic structure of the Pano linguistic group, four major Native American mitochondrial DNA (mtDNA) founder haplogroups were analyzed in 77 Amerindians from six villages of four Pano tribes (Katukina, Kaxináwa, Marúbo, and Yaminawa) located in the Brazilian Amazon. The central position of these tribes in the continent makes them relevant for attempts to reconstruct population movements in South America. Except for a single individual that presented an African haplogroup L, all remaining individuals presented one of the four Native American haplogroups. Significant heterogeneity was observed across the six Pano villages. Although Amerindian populations are usually characterized by considerable interpopulational diversity, the high heterogeneity level observed is unexpected if the strong ethnic, linguistic, and cultural homogeneity of the Pano linguistic group is taken into account. The present findings indicate that the ethnic, linguistic, and cultural homogeneity does not imply genetic homogeneity. Even though the genetic heterogeneity uncovered may be a female-specific process, the most probable explanation for that is the joint action of isolation and genetic drift as major factors influencing the genetic structure of the Pano linguistic group. keywords Mtdna, Genetic Diversity, Amerindians, South America The central west region of the Brazilian Amazon attracts attention because of its central position in South America, which makes it relevant for attempts to reconstruct the population movements and biological relationships of South American indigenous populations. Many tribes inhabit the western part of the northern region of Brazil, including several that are classified as Pano. They descend from populations that used to inhabit the eastern Andean slopes of Ecuador. At the end of the seventeenth century, they experienced some migrational events that culminated in their distribution along the Juruá and Purus Rivers in the Brazilian territory and in adjacent portions of Peru (Mohrenweiser et al. 1979; Salzano and Jacques 1979). At that time, they suffered a series of fissions that gave rise to the current tribes (Salzano and Jacques 1979). In spite of their large geographic distribution, the Pano group attracts attention for its remarkable ethnic homogeneity, reinforced by outstanding cultural and linguistic cohesion [End Page 93] (Erikson 1998). For instance, a linguistic analysis based on the cognate density disclosed a high degree of mutual intelligibility (Mohrenweiser et al. 1979), even greater than that encountered among the various subdivisions of the Yanomami (Spielman et al. 1974). Therefore, the several Pano groups are sometimes considered as members of a single Pano tribe (Mohrenweiser et al. 1979; Salzano and Jacques 1979). The genetic structure of the Pano group has not been comprehensively studied. So far, analyses of classical genetic markers, including both blood groups and erythrocyte and serum proteins (ABO, Kell, MNSs, P, Rh, Duffy, Kidd, Diego, haptoglobin, GC, transferrin, albumin, Lewis, ceruloplasmin, Gm, Km, phosphoglucomutase, acid phosphatase, galactose-1-phosphate uridyltransferase, and esterase D), revealed that the Brazilian and Peruvian Kaxináwa (one of the Pano tribes) can be grouped in a common gene pool, while Kaxináwa and Katukina (another Pano tribe) are somewhat more heterogeneous (Salzano and Jacques 1979). The only DNA markers that were exhaustively studied in Pano populations were two HLA-G polymorphisms: a cytosine deletion (ΔC) at codon 130 in exon 3 that determines a premature stop codon (Mendes-Junior et al. 2007a) and a 14-bp insertion/ deletion polymorphism at exon 8 of the HLA-G gene (Mendes-Junior et al. 2007b). While the ΔC was not observed in the four Pano tribes, the 14-bp insertion/deletion polymorphism revealed heterogeneous insertion frequencies that ranged from 36.11% (Marúbo) to 77.78% (Kaxináwa) (Mendes-Junior et al. 2007a, 2007b). Mitochondrial DNA (mtDNA) haplogroups, which present a matrilineal pattern of inheritance, have yet to be extensively analyzed among the Pano Indians. Although mtDNA markers have already been analyzed in many South American...

Arrival of Paleo-Indians to the Southern Cone of South America: New Clues from Mitogenomes

With analyses of entire mitogenomes, studies of Native American mitochondrial DNA (mtDNA) variation have entered the final phase of phylogenetic refinement: the dissection of the founding haplogroups into clades that arose in America during and after human arrival and spread. Ages and geographic distributions of these clades could provide novel clues on the colonization processes of the different regions of the double continent. As for the Southern Cone of South America, this approach has recently allowed the identification of two local clades (D1g and D1j) whose age estimates agree with the dating of the earliest archaeological sites in South America, indicating that Paleo-Indians might have reached that region from Beringia in less than 2000 years. In this study, we sequenced 46 mitogenomes belonging to two additional clades, termed B2i2 (former B2l) and C1b13, which were recently identified on the basis of mtDNA control-region data and whose geographical distributions appear to be restricted to Chile and Argentina. We confirm that their mutational motifs most likely arose in the Southern Cone region. However, the age estimate for B2i2 and C1b13 (11–13,000 years) appears to be younger than those of other local clades. The difference could reflect the different evolutionary origins of the distinct South American-specific sub-haplogroups, with some being already present, at different times and locations, at the very front of the expansion wave in South America, and others originating later in situ, when the tribalization process had already begun. A delayed origin of a few thousand years in one of the locally derived populations, possibly in the central part of Chile, would have limited the geographical and ethnic diffusion of B2i2 and explain the present-day occurrence that appears to be mainly confined to the Tehuelche and Araucanian-speaking groups.

Control Region Variability of Haplogroup C1d and the Tempo of the Peopling of the Americas

BackgroundAmong the founding mitochondrial haplogroups involved in the peopling of the Americas, haplogroup C1d has been viewed as problematic because of its phylogeny and because of the estimates of its antiquity, apparently being much younger than other founding haplogroups. Several recent analyses, based on data from the entire mitochondrial genome, have contributed to an advance in the resolution of these problems. The aim of our analysis is to compare the conclusions drawn from the available HVR-I and HVR-II data for haplogroup C1d with the ones based on whole mitochondrial genomes.Methodology/Principal FindingsHVR-I and HVR-II sequences defined as belonging to haplogroup C1d by standard criteria were gathered from the literature as well as from population studies carried out in Uruguay. Sequence phylogeny was reconstructed using median-joining networks, geographic distribution of lineages was analyzed and the age of the most recent common ancestor estimated using the ρ-statistic and two different mutation rates. The putative ancestral forms of the haplogroup were found to be more widespread than the derived lineages, and the lineages defined by np 194 were found to be widely distributed and of equivalent age.Conclusions/SignificanceThe analysis of control region sequences is found to still harbor great potential in tracing microevolutionary phenomena, especially those found to have occurred in more recent times. Based on the geographic distributions of the alleles of np 7697 and np 194, both discussed as possible basal mutations of the C1d phylogeny, we suggest that both alleles were part of the variability of the haplogroup at the time of its entrance. Moreover, based on the mutation rates of the different sites stated to be diagnostic, it is possible that the anomalies found when analyzing the haplogroup are due to paraphyly.

Large scale mitochondrial sequencing in Mexican Americans suggests a reappraisal of Native American origins

BackgroundThe Asian origin of Native Americans is largely accepted. However uncertainties persist regarding the source population(s) within Asia, the divergence and arrival time(s) of the founder groups, the number of expansion events, and migration routes into the New World. mtDNA data, presented over the past two decades, have been used to suggest a single-migration model for which the Beringian land mass plays an important role.ResultsIn our analysis of 568 mitochondrial genomes, the coalescent age estimates of shared roots between Native American and Siberian-Asian lineages, calculated using two different mutation rates, are A4 (27.5 ± 6.8 kya/22.7 ± 7.4 kya), C1 (21.4 ± 2.7 kya/16.4 ± 1.5 kya), C4 (21.0 ± 4.6 kya/20.0 ± 6.4 kya), and D4e1 (24.1 ± 9.0 kya/17.9 ± 10.0 kya). The coalescent age estimates of pan-American haplogroups calculated using the same two mutation rates (A2:19.5 ± 1.3 kya/16.1 ± 1.5 kya, B2:20.8 ± 2.0 kya/18.1 ± 2.4 kya, C1:21.4 ± 2.7 kya/16.4 ± 1.5 kya and D1:17.2 ± 2.0 kya/14.9 ± 2.2 kya) and estimates of population expansions within America (~21-16 kya), support the pre-Clovis occupation of the New World. The phylogeography of sublineages within American haplogroups A2, B2, D1 and the C1b, C1c andC1d subhaplogroups of C1 are complex and largely specific to geographical North, Central and South America. However some sub-branches (B2b, C1b, C1c, C1d and D1f) already existed in American founder haplogroups before expansion into the America.ConclusionsOur results suggest that Native American founders diverged from their Siberian-Asian progenitors sometime during the last glacial maximum (LGM) and expanded into America soon after the LGM peak (~20-16 kya). The phylogeography of haplogroup C1 suggest that this American founder haplogroup differentiated in Siberia-Asia. The situation is less clear for haplogroup B2, however haplogroups A2 and D1 may have differentiated soon after the Native American founders divergence. A moderate population bottle neck in American founder populations just before the expansion most plausibly resulted in few founder types in America. The similar estimates of the diversity indices and Bayesian skyline analysis in North America, Central America and South America suggest almost simultaneous (~ 2.0 ky from South to North America) colonization of these geographical regions with rapid population expansion differentiating into more or less regional branches across the pan-American haplogroups.

Mitochondrial DNA variability among eight Tikúna villages: Evidence for an intratribal genetic heterogeneity pattern

To study the genetic structure of the Tikúna tribe, four major Native American mitochondrial DNA (mtDNA) founder haplogroups were analyzed in 187 Amerindians from eight Tikúna villages located in the Brazilian Amazon. The central position of these villages in the continent makes them relevant for attempts to reconstruct population movements in South America. In this geographic region, there is particular concern regarding the genetic structure of the Tikúna tribe, formerly designated "enigmatic" due to its remarkable degree of intratribal homogeneity and the scarcity of private protein variants. In spite of its large population size and geographic distribution, the Tikúna tribe presents marked genetic and linguistic isolation. All individuals presented indigenous mtDNA haplogroups. An intratribal genetic heterogeneity pattern characterized by two highly homogeneous Tikúna groups that differ considerably from each other was observed. Such a finding was unexpected, since the Tikúna tribe is characterized by a social system that favors intratribal exogamy and patrilocality that would lead to a higher female migration rate and homogenization of the mtDNA gene pool. Demographic explosions and religious events, which significantly changed the sizes and compositions of many Tikúna villages, may be reflected in the genetic results presented here.

Updated Three-Stage Model for the Peopling of the Americas

BackgroundWe re-assess support for our three stage model for the peopling of the Americas in light of a recent report that identified nine non-Native American mitochondrial genome sequences that should not have been included in our initial analysis. Removal of these sequences results in the elimination of an early (i.e. ∼40,000 years ago) expansion signal we had proposed for the proto-Amerind population.Methodology/FindingsBayesian skyline plot analysis of a new dataset of Native American mitochondrial coding genomes confirms the absence of an early expansion signal for the proto-Amerind population and allows us to reduce the variation around our estimate of the New World founder population size. In addition, genetic variants that define New World founder haplogroups are used to estimate the amount of time required between divergence of proto-Amerinds from the Asian gene pool and expansion into the New World.Conclusions/SignificanceThe period of population isolation required for the generation of New World mitochondrial founder haplogroup-defining genetic variants makes the existence of three stages of colonization a logical conclusion. Thus, our three stage model remains an important and useful working hypothesis for researchers interested in the peopling of the Americas and the processes of colonization.

DNA from Pre-Clovis Human Coprolites in Oregon, North America

The timing of the first human migration into the Americas and its relation to the appearance of the Clovis technological complex in North America at about 11,000 to 10,800 radiocarbon years before the present (14C years B.P.) remains contentious. We establish that humans were present at Paisley 5 Mile Point Caves, in south-central Oregon, by 12,300 14C years B.P., through the recovery of human mitochondrial DNA (mtDNA) from coprolites, directly dated by accelerator mass spectrometry. The mtDNA corresponds to Native American founding haplogroups A2 and B2. The dates of the coprolites are >1000 14C years earlier than currently accepted dates for the Clovis complex.

Use of Y Chromosome and Mitochondrial DNA Population Structure in Tracing Human Migrations

Well-resolved molecular gene trees illustrate the concept of descent with modification and exhibit the opposing processes of drift and migration, both of which influence population structure. Phylogenies of the maternally inherited mtDNA genome and the paternally inherited portion of the nonrecombining Y chromosome retain sequential records of the accumulation of genetic diversity. Although knowledge regarding the diversity of the entire human genome will be needed to completely characterize human genetic evolution, these uniparentally inherited loci are unique indicators of gender in modulating the extant population structure. We compare and contrast these loci for patterns of continuity and discreteness and discuss how their phylogenetic diversity and progression provide means to disentangle ancient colonization events by pioneering migrants from subsequent overlying migrations. We introduce new results concerning Y chromosome founder haplogroups C, DE, and F that resolve their previous trifurcation and improve the harmony with the mtDNA recapitulation of the out-of-Africa migration.

Rapid deployment of the five founding Amerind mtDNA haplogroups via coastal and riverine colonization

Numerous studies of variation in mtDNA in Amerindian populations established that four haplogroups are present throughout both North and South America. These four haplogroups (A, B, C, and D) and perhaps a fifth (X) in North America are postulated to be present in the initial founding migration to the Americas. Furthermore, studies of ancient mtDNA in North America suggested long-term regional continuity of the frequencies of these founding haplogroups. Present-day tribal groups possess high frequencies of private mtDNA haplotypes (variants within the major haplogroups), consistent with early establishment of local isolation of regional populations. Clearly these patterns have implications for the mode of colonization of the hemisphere. Recently, the earlier consensus among archaeologists for an initial colonization by Clovis hunters arriving through an ice-free corridor and expanding in a "blitzkrieg " wave was shown to be inconsistent with extensive genetic variability in Native Americans; a coastal migration route avoids this problem. The present paper demonstrates through a computer simulation model how colonization along coasts and rivers could have rapidly spread the founding lineages widely through North America.