|
|
Post by Admin on Dec 2, 2021 19:02:33 GMT
Foundation Professor of Anthropology at the University of Nevada, Reno, G. Richard Scott, recently published a study where he and a team of experts from across the globe analyzed a large dental morphological database to evaluate the possible relationship between Native Americans and the Jomon people of Japan. This study was just published in the journal Paleoamerica under the title of “Peopling the Americas: Not ‘Out of Japan.” Scott’s research employed a new method of ancestry assessment using tooth crown and root morphology to evaluate over 1,500 dentitions from the Americas, Asia and the Pacific. This application, called rASUDAS2, found the Jomon and Ainu were primarily of Austral-Melanesian and Northeast Siberian descent. Only seven percent of the total Jomon and Ainu samples could be linked to non-Arctic Native Americans, considered the First Peoples.  Archaeologists have observed similarities between Jomon stone artifacts and those found in western North America with some going so far as suggesting earlier Japanese populations were ancestral to Native Americans. The second part of their theory, that Native Americans came to the Americas by way of maritime migration down the Pacific coastline, is not disputed in this paper. It does, however, counter arguments that Native Americans originated from the Jomon – an early hunter-gatherer population in Japan, best known for their very early development of pottery. “[The Jomon are] dentally very different from any Native Americans,” G. Richard Scott, foundation professor of anthropology in the College of Liberal Arts said. “These people did not come from Japan – but further north where they were sculpted by the last glacial maximum,” Scott said. Scott also noted that the teeth of the aboriginal Japanese populations show a significant Austral-Melanesia presence. There was slight affinity of the Jomon/Ainu to East Asians but almost no similarity to the dentitions of Native Americans. This research coincides with a recent study published in Science magazine. In this research, human footprints were discovered at an archaeological site in New Mexico that dates to the Last Glacial Maxima, around 27,000 years ago. This is now considered to the be the earliest and best documented site in North America to date. These data, along with Scott’s research, suggests that ancient Native Americans must have traveled va water transport along the coast. Although, he agrees that it’s not hard to envision people traveling up from Japan and down the Pacific coast, studies of ancient DNA point to an origin closer to Siberia. There is evidence that supports a Beringian-standstill because a site on the Yana River in Sakha, Russia dates to around 30,000-40,000-years-old. The ancestors of Native Americans may have been isolated in Beringia for many millennia before the coastal glaciers and ice sheets of North America diminished enough to allow for a coastal passage. “If people were here that early then it must have been a small group that left almost no ancestors,” Scott said. Scott is quick to point out that the research published on the archaeological site in New Mexico has nothing to do with population origins, only the timing of entry into the New World. His jointly authored study uses dental, genetic and craniometric data to address the question of biological relationships with Asian and Pacific populations. “We’re using biological evidence to say that it’s highly unlikely that they came out of Japan.” “I knew long ago that Jomon teeth were nothing like those of Native Americans – I’ve analyzed a lot of dental data from Native Circumpolar and North American populations and there is no similarity,” Scott said. |
|
|
|
Post by Admin on Dec 2, 2021 19:56:16 GMT
Peopling the Americas: Not “Out of Japan”
ABSTRACT
A widely accepted model for the peopling of the Americas postulates a source population in the Northeast Asian maritime region, which includes northern Japan. The model is based on similarities in stone artifacts (stemmed points) found in North American sites dating as early as 15,000 years ago and those of comparable age in Japan and neighboring regions of Northeast Asia. Here we show, on the basis of data and analyses in biological anthropology, that the people who made stemmed points in northern Japan (labeled “Incipient Jomon” in the archaeological literature) represent an unlikely source population for the indigenous peoples of the Western Hemisphere.
1. Out of Japan?
Despite a recent string of spectacular archaeological finds and the transformational impact of human paleo-genomics, many details regarding the peopling of the Americas remain unresolved. Recent discoveries have added considerable complexity to proposed models. These include terminal Pleistocene burials in central Alaska (Potter et al. 2014), 13,000-year-old footprints on the Pacific coast of North America (McLaren et al. 2018), a 14,500-year-old mastodon kill in northern Florida (Halligan et al. 2016), 15,000-year-old stemmed points in the Northwest region of the USA (Davis et al. 2019; Jenkins et al. 2012), and traces of an equally ancient coastal economy in Peru (Dillehay et al. 2017).
Even more than such remarkable archaeological discoveries, human genetics research has fundamentally altered the study of Native American origins (O’Rourke and Raff 2010; Raff 2021; Schurr 2004; Szathmary 1993). High-throughput sequencing approaches quickly moved the field beyond the mtDNA and Y-DNA studies of the 1990s (e.g., Bonatto and Salzano 1997; Forster et al. 1996; Torroni et al. 1992), and whole-genome analyses now are common (e.g., Dulik et al. 2012; Pinotti et al. 2019; Raghavan et al. 2015; Reich et al. 2012; Skoglund et al. 2015; Zegura et al. 2003). They include analyses of ancient DNA extracted from dated skeletal remains, which often have produced unexpected results and even stunning surprises (e.g., Moreno-Mayar et al. 2018; Rasmussen et al. 2014, 2015; Sikora et al. 2019).
The location of the Eurasian source population(s) of the First Peoples of the Western Hemisphere, and the time at which the Native American founder group(s) diverged from that population (or populations), remain points of contention, as does the number and timing of migration events (e.g., Moreno-Mayar et al. 2018; Ning et al. 2020; Reich 2018; Sikora et al. 2019; Yu et al. 2020). And if most anthropologists accept Beringia as the general region through which the founder groups moved into the Americas, both archaeologists and geneticists debate interior versus coastal routes (e.g., Fagundes et al. 2008; Graf and Buvit 2017; Perego et al. 2009; Potter et al. 2018; Scheib et al. 2018).
One of the more widely accepted models of Native American origins postulates a source population in the Northeast Asian maritime region and a coastal migration around the North Pacific Rim roughly 16,000–15,000 calendar years ago (cal yr BP) (e.g., Davis et al. 2019; Erlandson and Braje 2011). Like most models for the peopling of the Americas, it is based primarily on the analysis of archaeological data (e.g., Meltzer 2009; Potter et al. 2017; Stanford and Bradley 2012; West 1996). The original concept was proposed by N. N. Dikov (1979, 31–53), who discovered stemmed points on Kamchatka (i.e., North Pacific Rim) in the 1960s and 1970s and noted similarities to Western Stemmed points in mid-latitude North America. In recent years, the model has been bolstered by some of the spectacular discoveries mentioned above, as well as supporting data for early deglaciation of the Pacific Northwest coast and corresponding delay in the availability of an interior route (Darvill et al. 2018; Lesnek et al. 2018; Pedersen et al. 2016).
The model is grounded in similarities of stemmed points found in Japan and other parts of the Northeast Asian maritime area, including Korea and the Russian Far East, classified archaeologically as “Incipient Jomon” and dating to roughly 16,000–14,000 cal yr BP (e.g., Nagai 2007; Ono et al. 2002) with those of comparable age in interior Western North America (e.g., Cooper's Ferry, Idaho) and somewhat younger along the Pacific coast of North America (e.g., Arlington Springs on the Channel Islands, California),1 as well as the Pacific coastal zone of South America (e.g., Quebrada Jaguay in Peru) (Davis et al. 2019, 895; Erlandson 2013, 128–129; Erlandson and Braje 2011, 33–35; Sutton 2017, 2018) (Figure 1).2
|
|
|
|
Post by Admin on Dec 2, 2021 21:11:08 GMT
 Figure 1 Comparison of Cooper's Ferry projectile points (A, C, F, G, H) with late Pleistocene age Tachikawa-type stemmed points from the Kamishirataki 2 site on Hokkaido, Japan. (A) Stemmed projectile point haft fragment from LU3. (B) Illustration of Japanese Upper Paleolithic stemmed projectile point from the Kamishiritaki 2 site. (C) Blade fragment of projectile point from LU3. (D) Stemmed projectile point haft fragment from LU3. (E) Illustration of Japanese Upper Paleolithic stemmed projectile point from the Kamishiritaki 2 site. (F) Stemmed projectile point from PFA2. (G) Stemmed projectile point from PFA2. (H) Stemmed projectile point from PFA2. (I–K) Illustrations of Japanese Upper Paleolithic stemmed projectile points from the Kamishiritaki 2 site (reproduced from Davis et al. 2019, figure 5; copyright AAAS 2019). A “dual structure model” for the peopling of Japan is hypothesized by anthropologists, where the contemporary populations of Japan – including the mainland Japanese, the northern Ainu, and the southern Ryukyuan – are composed of two historical components: a very old hunter-gatherer population associated with Jomon pottery, spanning 16,000–2300 cal yr BP with even deeper roots in the early Upper Paleolithic of Japan (Adachi, Shinoda, and Izuho 2015), and a much more recent migration of East Asian rice farmers, the Yayoi culture, approximately 2300 cal yr BP (Habu 2004; Hanihara 1991). It is the earlier of the two components that is associated with the production of stemmed points in Japan 16,000–15,000 cal yr BP. According to the “Out of Japan” model, warming climates following the Last Glacial Maximum (after 18,000–17,000 cal yr BP) invited northward expansion of the people who made the Incipient Jomon points in the Northeast Asian maritime region, who already had developed a successful coastal economy with a marine diet and watercraft. They are assumed to have spread rapidly along the southern coast of Beringia (which has been characterized as a “kelp highway” (Erlandson et al. 2007)) and into the rich marine environments of the deglaciated Pacific Northwest of North America, bringing their distinctive stemmed points with them (Erlandson 2013).3 In our view, many elements of this model are highly plausible and some of it may be regarded as at least tentatively confirmed by research undertaken during the past two decades. We concur with Erlandson (2013) and others (Davis et al. 2019; Dixon 2001; Erlandson et al. 2007) that Native Americans probably dispersed initially along the Pacific Northwest coast with the aid of watercraft and subsequently spread down the Pacific coast of South America, and that the first occupants of mid-latitude North America probably pursued a coastal economy. Moreover, whatever the biological relationship between the people who made stemmed points in Japan and California 15,000–13,000 cal yr BP, the similarities in their artifacts are striking (e.g., Davis et al. 2019, figure 5; Erlandson and Braje 2011, figure 4). Given the explosive growth of genetic data in recent years, the time is right to re-evaluate hypotheses regarding the peopling of the Americas with a synthesis of biological and archaeological evidence (e.g., Pinotti and Santos 2020; Raff and Bolnick 2015). In what follows, we address the “Out of Japan” hypothesis with the data and methods of biological anthropology – both anatomical and genetic – and show that the people who made the Incipient Jomon artifacts are an unlikely source for Indigenous Americans. We suggest the source populations for the latter must be sought elsewhere. |
|
|
|
Post by Admin on Dec 2, 2021 22:05:13 GMT
2. Craniometrics
Human cranial variation has a long and, originally, wrought history within the scientific investigation of the peopling of the Americas. In the nineteenth century, anatomists in the United States measured cranial size across Indigenous peoples in the Western Hemisphere with the intent of identifying differences in intelligence compared to Europeans (e.g., Morton and Combe 1839; see early overview by Hrdlička 1919). Craniometrics gradually evolved to focus less on racialized questions and more on understanding the ancestral affinities of human populations. Twenty years ago, human cranial variation joined dental variation and molecular genetics as a key dataset for querying the biological affinities of the Indigenous people living in the Western Hemisphere (e.g., González-José et al. 2005; Herrera et al. 2017; Hubbe, Neves, and Harvati 2010; Hubbe et al. 2020; Kuzminsky, Coonerty, and Fehren-Schmitz 2017; Neves and Pucciarelli 1991).
Initially, craniometric evidence suggested that the earliest people occupying the Americas (< 8000 years ago) differed from later people, with the former having crania that were more anteroposteriorly elongated (e.g., González-José et al. 2005; Neves and Hubbe 2005; Neves and Pucciarelli 1991). In contrast to other lines of evidence, these cranial shape data suggested that the earliest people in the Americas had a stronger biological affinity with people living in the South Pacific rather than East Asia, and perhaps evidenced two waves of migration (e.g., González-José et al. 2005; Hubbe, Neves, and Harvati 2010; Neves and Hubbe 2005; Neves and Pucciarelli 1991).
As larger sample sizes and more nuanced analyses became available, the morphological distinction between early and later Indigenous Americans was increasingly realized to be less obvious or abrupt than originally thought (Kuzminsky, Coonerty, and Fehren-Schmitz 2017, 2018). However, the craniofacial shapes of Indigenous populations living in the Americas did change over time, providing a rich dataset for probing the biological affinities and models of dispersion among populations within the Americas (e.g., Herrera et al. 2017; Menéndez et al. 2015).
In terms of understanding the deeper ancestry of Indigenous Americans, four skulls from Quintana Roo, Mexico, add an interesting twist (Hubbe, Neves, and Harvati 2010). These skeletal remains are from people who lived 13,000–12,000 cal yr BP on the Yucatan peninsula (Chatters et al. 2014). Two of the skulls show morphological affinities with North American arctic populations; another has strong similarities to Paleoamericans in South America; and the fourth has similarities to Europeans (Hubbe et al. 2020). As the authors of that study note, “At the very least, it provokes researchers to reevaluate the validity of extrapolations made in the past” (Hubbe et al. 2020, 16).
To infer ancestry from anatomical variation, that variation would ideally be influenced by many different genomic loci and result from only neutral evolution. This is a high hurdle for human cranial variation, given the complex interplay of genetic, non-genetic, and developmental forces that influence its shape, and how intertwined cranial variation is with mastication, thermoregulation, mate choice, etc. (Lieberman 2011). Quantitative genetic-driven studies of human cranial variation enable us to unravel some of this intricacy (reviewed in von Cramon-Taubadel 2014).
Two recent studies are of particular relevance to the use of Indigenous American craniofacial variation to infer ancestry. De Azevedo et al.’s (2017) study of Indigenous Americans found that the observed craniofacial variation accords with a single ancestral source, supporting the “Beringian standstill” model (Tamm et al. 2007). They also found that the variation accrued since that diverse ancestral population deviates from a neutral evolutionary model, indicating that microevolutionary forces have been at play (de Azevedo et al. 2017).
Katz, Grote, and Weaver (2017) explored how the shift from foraging to farming may have influenced human craniofacial form globally. Results showed a modest but significant directional effect between populations that rely on the much softer versus tougher diets (Katz, Grote, and Weaver 2017). Given the Katz, Grote, and Weaver (2017) results, it is quite likely that the diversity of subsistence strategies that Indigenous Americans adopted as they migrated across the Western Hemisphere contributed to the microevolutionary forces inferred by de Azevedo et al. (2017). Considering the vast latitudinal range of the Americas, climate likely played a role, too (Menendez 2018; von Cramon-Taubadel 2014), further obscuring evidence of ancestry.
In our view, craniometrics does not provide an adequate basis for identifying the source population(s) of Native Americans.
|
|
|
|
Post by Admin on Dec 3, 2021 0:30:35 GMT
3. Dental anthropology
One hundred years ago, Aleš Hrdlička (1920) wrote a seminal paper on shovel-shaped incisors and demonstrated how a morphological crown trait could provide clues on long-term human population history. Specifically, he noted the widespread occurrence of the trait in Native Americans, which differs significantly from the lower frequencies and trait expressions typical of Euro- and African-Americans.4 Half a century later, Christy G. Turner II (1971) used another trait, a three-rooted lower first molar (3RM1), to develop a model for the peopling of the Americas,5 which subsequently became a component of the “three-wave model,” based on linguistic, dental, and genetic data (Greenberg, Turner, and Zegura 1986).
Aware of the limitations of single traits (or genes) for reconstructing population history, Turner and his students later identified and classified over three dozen crown and root traits that culminated in the Arizona State University Dental Anthropology System (ASUDAS) (Edgar 2017; Turner, Nichol, and Scott 1991; Scott and Irish 2017). This standardization ushered in a new era of global dental morphology research. Detailed trait descriptions and the availability of plaques for many traits has significantly reduced observer error, a problem in pre-1970s research (Scott, Maier, and Heim 2016; Scott and Pilloud 2019).
Most dental morphological traits are either absent or exhibit a range of expression from slight to pronounced when present. Although twin and family studies show dental traits are under strong genetic control (Hughes and Townsend 2013; Paul et al. 2020; Townsend et al. 2009), they do not have simple Mendelian modes of inheritance like blood group antigens, serum proteins, and other simple genetic markers (cf. Roychoudhury and Nei 1988). Therefore, they have been assumed to be quasicontinuous or threshold traits with polygenic modes of inheritance (Harris 1977; Scott 1973). For that reason, nonmetric dental characters are characterized by “trait frequencies” rather than gene frequencies. Trait frequencies represent the total frequency of presence, but in some instances, trait frequency is defined by “frequency above a breakpoint,” and consequently are studied as though they are a presence/absence phenomenon.
Although the identification of major gene effects on crown trait expression met with limited success in early studies (e.g., Kolakowski, Harris, and Bailit 1980; Nichol 1989, 1990), researchers have demonstrated that shovel-shaped incisors are partly controlled (ca. 19%) by the EDAR V370A allele (Kimura et al. 2009) that has effects on hair, skin, and teeth. Other dental traits, including lower molar cusp number, are also linked to this allele (Park et al. 2012). Increasingly, dental trait evolution is being investigated as part of a pleiotropic milieu (e.g., Hlusko et al. 2018). Although population variation in crown and root traits has been dictated primarily by random factors (genetic drift, founder effect) associated with time since divergence and geographic isolation (Monson, Fecker, and Scherrer 2020; Rathmann and Reyes-Centeno 2020), some traits may be indirectly affected by natural selection acting on variables critical to survival and reproduction (i.e., they can act like “genetic hitchhikers” (Scott et al. 2018a)).
Researchers have recently used genomic data in concert with dental morphological data to reconstruct population history (Hubbard 2012; Hubbard, Guatelli-Steinberg, and Irish 2015; Irish et al. 2020; Rathmann and Reyes-Centeno 2020; Rathmann et al. 2017; Reyes-Centeno et al. 2017). Although there is no one-to-one correspondence in results, these analyses show dental morphological (nonmetric) traits produce high and significant correlations with neutral genomic data. Rathmann and Reyes-Centeno (2020) note some traits are closely in line with neutral genomic markers while other traits show patterns of variation consistent with the action of selection. Irish et al. (2020, 25) conclude:
The bottom line then, in conjunction with the recent heritability studies and population analyses, and despite potential concerns (sex dimorphism, selection, etc.), is that dental nonmetric traits actually can and do work well as proxies for neutral genomic data.
Additionally, crown and root morphologic traits are highly resistant to change when populations migrate from one area to another, no matter what new climatic, dietary, and disease factors are encountered. When Europeans colonized the Americas, Africa, and Australia, their dental traits continued to exhibit a Eurodont pattern (Scott et al. 2013), one that provides a stark contrast to the teeth of the indigenous populations of the other three continents.
|
|
