G. Richard Scott

Beringia and the global dispersal of modern humans

Until recently, the settlement of the Americas seemed largely divorced from the out‐of‐Africa dispersal of anatomically modern humans, which began at least 50,000 years ago. Native Americans were thought to represent a small subset of the Eurasian population that migrated to the Western Hemisphere less than 15,000 years ago. Archeological discoveries since 2000 reveal, however, that Homo sapiens occupied the high‐latitude region between Northeast Asia and northwest North America (that is, Beringia) before 30,000 years ago and the Last Glacial Maximum (LGM). The settlement of Beringia now appears to have been part of modern human dispersal in northern Eurasia. A 2007 model, the Beringian Standstill Hypothesis, which is based on analysis of mitochondrial DNA (mtDNA) in living people, derives Native Americans from a population that occupied Beringia during the LGM. The model suggests a parallel between ancestral Native Americans and modern human populations that retreated to refugia in other parts of the world during the arid LGM. It is supported by evidence of comparatively mild climates and rich biota in south‐central Beringia at this time (30,000‐15,000 years ago). These and other developments suggest that the settlement of the Americas may be integrated with the global dispersal of modern humans.

MEN, WOMEN, AND CHILDREN STARVING : ARCHAEOLOGY OF THE DONNER FAMILY CAMP

In spring of 1846, the George and Jacob Donner families and some 80 traveling companions began their overland trek to California. When the party ascended the Sierra Nevada in late October, a snowstorm forced the group to bivouac. At this point, the train became separated into two contingents; the larger party camped near Donner Lake and the smaller group—including the Donner families—settled at Alder Creek. Though written accounts from the Lake site imply many resorted to cannibalism, no such records exist for Alder Creek. Here we present archaeological findings that support identification of the Alder Creek camp. We triangulate between historical context, archaeological traces of the camp, and osteological remains to examine the human condition amid the backdrops of starvation and cannibalism. A stepped analytical approach was developed to examine the site’s fragmentary bone assemblage (n = 16,204). Macroscopic and histological analyses indicate that the emigrants consumed domestic cattle and horse and procured wild game, including deer, rabbit, and rodent. Bladed tools were used to extensively process animal tissue. Moreover, bone was being reduced to small fragments; pot polish indicates these fragments were boiled to extract grease. It remains inconclusive, however, whether such processing, or the assemblage, includes human tissue.

The Relationship Between Carabelli's Trait and the Protostylid

In contrast to living pongids and fossil hominoids the teeth of Homo sapiens do not exhibit distinct cingular shelves. Modern human teeth do, however, possess an active cingular zone which serves as the point of origin for specific accessory cusps (BUTLER, Biol Rev 31:30, 1965). In the maxilla, this zone is active primarily on the lingual surfaces of the anterior teeth and the molars where lingual tubercles and Carabellis trait are expressed, respectively. The mandibular teeth rarely exhibit any development from the lingual cingular zone, but a cingular trait of the lower molars referred to as the protostylid is sometimes evident on the buccal surface of the mesiobuccal cusp. In a previous study, association was demonstrated between lingual tubercles of the maxillary central incisor and canine (SCOTT, J Dent Res, 56:1192, 1977). To examine further the developmental interrelationships between traits derived from the cingular zone, the expressions of the lingual cingula of the maxillary molars (i.e. Carabellis trait) and the buccal cingula of the mandibular molars (i.e. the protostylid) were subjected to correlation analysis. Six samples of Papago, Navajo, and Hopi Indians (n = 676) from the American Southwest were studied to measure association between Carabellis trait and the protostylid. The expression of both cingular traits ranges from absence through subtle grooves and ridges to varying tubercle outlines and free-standing cusps, so ranked scales were used to score the degree of trait development. For Carabellis trait, the classification includes absence and 9 degrees of trait presence while the scale for the protostylid follows DAHLBERG (In: BROTHWELL, D.R. (ed), Dental Anthropology, 1963, p 149) who defined 6 grades (excluding buccal pits) with absence and 5 degrees of trait presence. Although both traits can be expressed on all 3 molars of their respective fields, they are in highest frequency on the first molars. Analysis was therefore restricted to first molars as their cingular phenotypes best reflect the underlying genotype (SOFAER ET AL, Arch Oral Biol, 17: 811, 1972). Kendalls rank order correlation coefficient tau and the phi coefficient based on 2 X 2 contingency analysis were both used to estimate the significance and degree of association. Since no significant sex differences were evident for the 2 traits, data on males and females were combined for analysis. The tau values shown in the table indicate a consistently high correlation between Carabellis trait and the protostylid. All of the values differ significantly from zero and, with only one exception, significance is at the 0.01 level. The

Anthropological Perspectives on Tooth Morphology: Basque dental morphology and the “Eurodont” dental pattern

The Basque peoples of northern Spain and southern France have long held the interest of anthropologists and linguists. Linguistically, they are considered an isolate with no close ties to any surrounding Indo-European-speaking group. This linguistic peculiarity raised expectations that a similar situation would be found at the biological level. In the early twentieth century, studies of Basque cranial morphology were mostly typological in nature, as researchers made every effort to identify a distinctive Basque type (MacClancy 1993 ; de la R ú a et al. 2005 /2006 for a review). In the 1930s, the discovery of remains at the site of Urtiaga (Gipuzkoa), which presumably dated to the Upper Paleolithic, pushed the origins of the Basque population further back in time. This led to a popular hypothesis that the “Basque type” refl ected an indigenous and local evolution of the Cro-Magnon race (Aranzadi and Barandiaran 1948 ). Later radiometric dating of these skulls unequivocally placed the Urtiaga remains in the more recent Bronze Age, a fi nding that challenged the Cro-Magnon hypothesis of Basque origins (Altuna and de la R ú a 1989 ). In the mid-twentieth century, blood antigen typing replaced cranial typology in addressing questions of population origins. Cumulative information on more than a single locus seemed to confi rm the idea that Basques were a locally evolved population that had descended from Upper Paleolithic Europeans. Seemingly, Basques survived the impact of genetic admixture with later migrants (Near East Neolithic farmers) to a greater extent than other European populations

The Uto‐Aztecan premolar among North and South Amerindians: Geographic variation and genetics

The Uto-Aztecan premolar (UAP) is a dental polymorphism characterized by an exaggerated distobuccal rotation of the paracone in combination with the presence of a fossa at the intersection of the distal occlusal ridge and distal marginal ridge of upper first premolars. This trait is important because, unlike other dental variants, it has been found exclusively in Native American populations. However, the traits temporal and geographic variation has never been fully documented. The discovery of a Uto-Aztecan premolar in a prehistoric skeletal series from northern South America calls into question the presumed linguistic and geographic limits of this trait. We examined published and unpublished data for this rare but highly distinctive trait in samples representing over 5,000 Native Americans from North and South America. Our findings in living Southwest Amerindian populations corroborate the notion that the variable goes beyond the bounds of the Uto-Aztecan language family. It is found in prehistoric Native Americans from South America, eastern North America, Northern and Central Mexico, and in living and prehistoric populations in the American Southwest that are not members of the Uto-Aztecan language stock. The chronology of samples, its geographic distribution, and trait frequencies suggests a North American origin (Southwest) for UAP perhaps between 15,000 BP and 4,000 BP and a rapid and widespread dispersal into South America during the late Holocene. Family data indicate that it may represent an autosomal recessive mutation that occurred after the peopling of the Americas as its geographic range appears to be limited to North and South Amerindian populations.

Technique and Application in Dental Anthropology: History of dental anthropology

Introduction In 1991, Albert A. Dahlberg wrote “Historical perspective of dental anthropology” for the volume Advances in Dental Anthropology (Kelley and Larsen, 1991). A few years later, the senior author (Scott, 1997) wrote an historical paper on “Dental anthropology” for Frank Spencers 1997 edited volume on the History of Physical Anthropology . Dahlberg was both a dentist and a pioneer in the field of dental anthropology. Because of those two abiding interests, his historical treatment focused as much on developments in oral biology as on the history of dental anthropology per se. Scott, a physical anthropologist, dealt with the early history of dental research, but the overall focus of his article revolved around the manner in which teeth have been used in anthropological research. Given the recency of these two articles, we do not want to simply reiterate points already made. Moreover, in no way is this general contribution comparable to articles on the history of dental anthropology in circumscribed geographic areas, such as those written for Australia (Brown, 1992, 1998) and Hungary (Kosa, 1993). We applaud these efforts and encourage other workers to document the history of the field in their country or region. Our goal is to focus broadly on the growth of dental anthropology during the twentieth century and comment on potential directions in the twenty-first century.

Interaction between shoveling of the maxillary and mandibular incisors.

To determine if maxillary and mandibular incisor shoveling is developmentally interrelated, observations on this trait were made on 1251 U.S. Southwest Indians and 113 American whites. Because of the difficulties in metrically quantifying the size of lingual marginal ridges, ranked scales dividing the continuum of shoveling into approximately equal intervals were used to score trait expression. Shoveling for the larger and more variable maxillary incisors was classified by absence and seven grades of trait presence, while the lower incisor shoveling classification included only absence and three degrees of presence. Kendalls rank order correlation tau was employed to assess the significance and degree of association in shoveling expression for six pair-wise comparisons involving UI1, UI2, LI1 and L12. In the table, the array of tau values for the eleven samples is presented for each pair-wise comparison. As 59 of the 66 correlations were significant at the 0.01 level, only nonsignificant values or those significant at the 0.05 level are noted in the table. A distribution of sample tau values approximates normality, so means are provided as the best estimate of the population tau for each comparison (KENDALL, Rank Correlation Methods, 1970). The median correlations, which are highly congruent with the means, confirm the symmetrical nature of the sampling distributions of tau. The consistently significant correlation values for all six comparisons indicate clearly a general within and between jaw field for lingual marginal ridge development on the incisors.

The Dentition of American Indians: Evolutionary Results and Demographic Implications Following Colonization from Siberia

This chapter uses dental morphology to make inferences about how the New World was first colonized. The major emphasis is on the initial Macro-Indian migration based on dental traits observed in Paleo-Indian, Archaic, and more recent prehistoric crania. The major results are as follows: (1) Arctic and Subarctic native dentitions differ enough from those of Macro-Indians to indicate separate migrations. (2) Clustered MMD values show three Macro-Indian branches of North Americans, South Americans, and mixed North and South. (3) There is no marked branching depth for these three dental divisions, which fits the hypothesis of a single rapid Paleo-Indian colonization event. (4) The minimally divergent North and South American dental divisions are most likely the microevolutionary result of dispersal-dependent population structure and lineage effects. (5) No genetic bottlenecking can be identified at Panama. (6) The small amount of New World internal dental divergence favors colonization of South America soon after the settlement of North America. (7) There are no obvious clines, frequency trends, or geographic groupings for individual dental traits. This suggests little or no selection and that after leaving Siberia, population size increased sufficiently to limit genetic drift. (8) There is no sign of any Old World or Oceanic dental pattern other than Northeast Asian Sinodonty. All things considered, including New World and Siberian linguistics, archaeology, genetics, route considerations, and relevant natural history, dental analysis supports the Late Pleistocene ice-free corridor, Clovis or epi-Clovis settlement hypothesis, and the Greenberg Amerind or Macro-Indian language evolution model.

Brief communication: two-rooted lower canines--a European trait and sensitive indicator of admixture across Eurasia.

With the exception of Carabellis trait, the European dentition is better known for the morphological traits that it does not exhibit rather than the ones that it does. One root trait, however, runs counter to the characterization of reduced and simplified European crowns and roots. Although a rare trait in general, two-rooted lower canines are much more common in Europeans than in any other regional grouping and, given adequate sample sizes, can be useful in evaluating gene flow between Europeans and neighboring groups. In European samples, two-rooted lower canines consistently exhibit frequencies of 5-8%. In our sample from northern Spain, the trait attains a frequency of almost 10%. In contrast, in Sub-Saharan Africans the trait is virtually unknown while in Asian and Asian-derived populations, it varies between 0.0 and 1.0%. Here we show that two-rooted canine frequencies for new migrants along the western frontiers of China and Mongolia ranged from 0-4%. These data suggest European-derived populations migrated into western China (Xinjiang Province) and Mongolia (Bayan Olgii Aimag) sometime during the late Bronze age (1000-400 BCE).

Environmental selection during the last ice age on the mother-to-infant transmission of vitamin D and fatty acids through breast milk

Significance The frequency of the human-specific EDAR V370A isoform is highly elevated in North and East Asian populations. The gene is known to have several pleiotropic effects, among which are sweat gland density and ductal branching in the mammary gland. The former has led some geneticists to argue that the near-fixation of this allele was caused by selection for modulation of thermoregulatory sweating. We provide an alternative hypothesis, that selection instead acted on the allele’s effect of increasing ductal branching in the mammary gland, thereby amplifying the transfer of critical nutrients to infants via mother’s milk. This is likely to have occurred during the Last Glacial Maximum when a human population was genetically isolated in the high-latitude environment of the Beringia. Because of the ubiquitous adaptability of our material culture, some human populations have occupied extreme environments that intensified selection on existing genomic variation. By 32,000 years ago, people were living in Arctic Beringia, and during the Last Glacial Maximum (LGM; 28,000–18,000 y ago), they likely persisted in the Beringian refugium. Such high latitudes provide only very low levels of UV radiation, and can thereby lead to dangerously low levels of biosynthesized vitamin D. The physiological effects of vitamin D deficiency range from reduced dietary absorption of calcium to a compromised immune system and modified adipose tissue function. The ectodysplasin A receptor (EDAR) gene has a range of pleiotropic effects, including sweat gland density, incisor shoveling, and mammary gland ductal branching. The frequency of the human-specific EDAR V370A allele appears to be uniquely elevated in North and East Asian and New World populations due to a bout of positive selection likely to have occurred circa 20,000 y ago. The dental pleiotropic effects of this allele suggest an even higher occurrence among indigenous people in the Western Hemisphere before European colonization. We hypothesize that selection on EDAR V370A occurred in the Beringian refugium because it increases mammary ductal branching, and thereby may amplify the transfer of critical nutrients in vitamin D-deficient conditions to infants via mothers’ milk. This hypothesized selective context for EDAR V370A was likely intertwined with selection on the fatty acid desaturase (FADS) gene cluster because it is known to modulate lipid profiles transmitted to milk from a vitamin D-rich diet high in omega-3 fatty acids.