Characteristic Dental Traits

2020 ◽  
pp. 135-161
Author(s):  
Hiroyuki Yamada
Keyword(s):  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Petra G. Šimková ◽  
Gerhard W. Weber ◽  
Fernando V. Ramirez Rozzi ◽  
Lotfi Slimani ◽  
Jérémy Sadoine ◽  
...  

AbstractThe Baka Pygmies are known for their short stature resulting from a reduced growth rate during infancy. They are peculiar also for their teeth erupt earlier than in any other African population, and their posterior dentition is larger than in non-Pygmy populations. However, the Baka’s dental morphology, like several other aspects of their biology, is still understudied. Here, we explore the variation of the Baka’s deciduous upper and lower second molars (dm2s) in comparison to a geographically heterogeneous human sample by means of 3D geometric morphometrics and analysis of dental traits. Our results show that the different populations largely overlap based on the shape of their dm2s, especially the lower ones. Their distal region and the height of the dentinal crown differ the most, with the Baka showing the most extreme range of variation. Upper and lower dm2s covary to a great extent (RV = 0.82). The Baka’s and South Americans’ dm2s were confirmed among the largest in our sample. Despite the Baka’s unique growth pattern, long-lasting isolation, and extreme dental variation, it is not possible to distinguish them from other populations based on their dm2s’ morphology only.


2014 ◽  
Vol 77 (2) ◽  
pp. 151-174 ◽  
Author(s):  
Anahit Yu. Khudaverdyan

Abstract The aim of the study is the assessment of biological distance between populations from Transcaucasia on the basis of the frequency of dental morphological traits. It is well known that these traits are characterised by a high inter-population differentiation, low sexual dimorphism, and their recording is loaded by relatively small intra and inter observer error. The dental morphological traits are successfully used in the description and explanation of the microevolutionary and ethnogenetic processes. This paper presents the results of the odontological differentiation of human populations from Transcaucasia. The comparative analysis was carried out on the basis of 12 groups. From the obtained results, we can draw the following conclusions: The populations of Armenian Highland and Georgia can be differentiated as far as the frequency of dental morphological traits are concerned. They also do not exhibit similar intragroup variability. Biocultural diversity of ancient Transcaucasian populations has not been studied extensively; therefore, delineating some of the patterns of phenotypic variation may be useful for understanding their ongoing evolution.


2014 ◽  
Vol 69 ◽  
pp. 123-128 ◽  
Author(s):  
Katherine Carter ◽  
Steven Worthington ◽  
Tanya M. Smith
Keyword(s):  

2018 ◽  
Vol 29 (4) ◽  
pp. 696-717 ◽  
Author(s):  
Haagen D. Klaus ◽  
Walter Alva ◽  
Steve Bourget ◽  
Luis Chero

Between AD 100 and 800, the Moche culture emerged on the north coast of Peru. Diverse debates surround the nature of Moche territorial and political centralization, sociopolitical identities, and the internal social diversity of Moche society. Here we address some of these issues in a biodistance study based on phenotypic variation of inherited dental traits within and between 36 individuals in the royal tombs of Sipán (Lambayeque valley), Úcupe (Zaña valley), and Dos Cabezas (Jequetepeque valley). Metric and nonmetric dental trait data were analyzed using hierarchical cluster and R-matrix analyses. The results independently indicate that the highest-level Sipán and Dos Cabezas lords likely represented different endogamous kin groups, while limited gene flow occurred between groups of Moche lower nobility between the Lambayeque and Jequetepeque regions. Although biology and material cultural link the Lord of Úcupe to Dos Cabezas, many objects in his tomb demonstrate his participation the world of the Sipán elites. These Moche lords were, on some levels, bioculturally interconnected. Nonetheless, the data broadly lend support to a “many Moches” model of sociopolitical structure, further casting doubt on earlier one-dimensional visions of a centralized hegemonic Moche polity.


2020 ◽  
Vol 117 (20) ◽  
pp. 10769-10777 ◽  
Author(s):  
Hannes Rathmann ◽  
Hugo Reyes-Centeno

Researchers commonly rely on human dental morphological features in order to reconstruct genetic affinities among past individuals and populations, particularly since teeth are often the best preserved part of a human skeleton. Tooth form is considered to be highly heritable and selectively neutral and, therefore, to be an excellent proxy for DNA when none is available. However, until today, it remains poorly understood whether certain dental traits or trait combinations preserve neutral genomic signatures to a greater degree than others. Here, we address this long-standing research gap by systematically testing the utility of 27 common dental traits and >134 million possible trait combinations in reflecting neutral genomic variation in a worldwide sample of modern human populations. Our analyses reveal that not all traits are equally well-suited for reconstructing population affinities. Whereas some traits largely reflect neutral variation and therefore evolved primarily as a result of genetic drift, others can be linked to nonstochastic processes such as natural selection or hominin admixture. We also demonstrate that reconstructions of population affinity based on many traits are not necessarily more reliable than those based on only a few traits. Importantly, we find a set of highly diagnostic trait combinations that preserve neutral genetic signals best (up to x∼r = 0.580; 95% r range = 0.293 to 0.758; P = 0.001). We propose that these trait combinations should be prioritized in future research, as they allow for more accurate inferences about past human population dynamics when using dental morphology as a proxy for DNA.


2020 ◽  
pp. 1-4
Author(s):  
Nancy L. Segal

Abstract John C. Loehlin, professor of psychology at the University of Texas, at Austin, passed away on August 9, 2020. John was 94 years of age. He will be remembered for his seminal contributions that have furthered the field of twin research in so many ways. An overview of his career is presented, with fond memories from his son and several colleagues. This tribute is followed by reviews of twin research on cognitive skills and social mobility, risk of subarachnoid hemorrhage, heritability of selected dental traits and twin-to-twin transfusion syndrome. Finally, twin-related topics of human interest include identical twins with different health histories, twins born 97 days apart, retiring twin tennis players, TikTok twins and twin reality stars.


2019 ◽  
Vol 5 (1) ◽  
pp. eaau0930 ◽  
Author(s):  
Song Xing ◽  
Paul Tafforeau ◽  
Mackie O’Hara ◽  
Mario Modesto-Mata ◽  
Laura Martín-Francés ◽  
...  

Several human dental traits typical of modern humans appear to be associated with the prolonged period of development that is a key human attribute. Understanding when, and in which early hominins, these dental traits first appeared is thus of strong interest. Using x-ray multiresolution synchrotron phase-contrast microtomography, we quantify dental growth and development in an archaicHomojuvenile from the Xujiayao site in northern China dating to 161,000–224,000 years or 104,000–125,000 years before present. Despite the archaic morphology of Xujiayao hominins, most aspects of dental development of this juvenile fall within modern human ranges (e.g., prolonged crown formation time and delayed first molar eruption). For its estimated age-at-death (6.5 years), its state of dental development is comparable to that of equivalently aged modern children. These findings suggest that several facets of modern human dental growth and development evolved in East Asia before the appearance of fully modern human morphology.


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