scholarly journals Testing the utility of dental morphological trait combinations for inferring human neutral genetic variation

2020 ◽  
Vol 117 (20) ◽  
pp. 10769-10777 ◽  
Author(s):  
Hannes Rathmann ◽  
Hugo Reyes-Centeno
Keyword(s):  
Modern Human ◽  
Genomic Variation ◽  
Future Research ◽  
Human Populations ◽  
Dental Morphology ◽  
Genomic Signatures ◽  
Neutral Genetic Variation ◽  
Tooth Form ◽  
Dental Traits ◽  
Population Affinity

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.

scholarly journals European early modern humans and the fate of the Neandertals

2007 ◽  
Vol 104 (18) ◽  
pp. 7367-7372 ◽  
Author(s):  
Erik Trinkaus
Keyword(s):  
Early Modern ◽  
Molecular Data ◽  
Modern Human ◽  
Morphological Features ◽  
Middle Paleolithic ◽  
Human Populations ◽  
Dental Morphology ◽  
Modern Humans ◽  
Morphological Aspects ◽  
Early Modern Humans

A consideration of the morphological aspects of the earliest modern humans in Europe (more than ≈33,000 B.P.) and the subsequent Gravettian human remains indicates that they possess an anatomical pattern congruent with the autapomorphic (derived) morphology of the earliest (Middle Paleolithic) African modern humans. However, they exhibit a variable suite of features that are either distinctive Neandertal traits and/or plesiomorphic (ancestral) aspects that had been lost among the African Middle Paleolithic modern humans. These features include aspects of neurocranial shape, basicranial external morphology, mandibular ramal and symphyseal form, dental morphology and size, and anteroposterior dental proportions, as well as aspects of the clavicles, scapulae, metacarpals, and appendicular proportions. The ubiquitous and variable presence of these morphological features in the European earlier modern human samples can only be parsimoniously explained as a product of modest levels of assimilation of Neandertals into early modern human populations as the latter dispersed across Europe. This interpretation is in agreement with current analyses of recent and past human molecular data.

scholarly journals Human Prehistoric Demography Revealed by the Polymorphic Pattern of CpG Transitions

2020 ◽  
Vol 37 (9) ◽  
pp. 2691-2698 ◽  
Author(s):  
Xiaoming Liu
Keyword(s):  
Population Dynamics ◽  
Population Expansion ◽  
Future Research ◽  
Human Populations ◽  
Neolithic Revolution ◽  
Cpg Sites ◽  
Hunting And Gathering ◽  
Genome Wide ◽  
Polymorphic Pattern ◽  
Improved Model

Abstract The prehistoric demography of human populations is an essential piece of information for illustrating our evolution. Despite its importance and the advancement of ancient DNA studies, our knowledge of human evolution is still limited, which is also the case for relatively recent population dynamics during and around the Holocene. Here, we inferred detailed demographic histories from 1 to 40 ka for 24 population samples using an improved model-flexible method with 36 million genome-wide noncoding CpG sites. Our results showed many population growth events that were likely due to the Neolithic Revolution (i.e., the shift from hunting and gathering to agriculture and settlement). Our results help to provide a clearer picture of human prehistoric demography, confirming the significant impact of agriculture on population expansion, and provide new hypotheses and directions for future research.

scholarly journals Morphological variation of the deciduous second molars in the Baka Pygmies

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Petra G. Šimková ◽  
Gerhard W. Weber ◽  
Fernando V. Ramirez Rozzi ◽  
Lotfi Slimani ◽  
Jérémy Sadoine ◽  
...  
Keyword(s):  
Growth Rate ◽  
Morphological Variation ◽  
Growth Pattern ◽  
Distal Region ◽  
Dental Morphology ◽  
Human Sample ◽  
Different Populations ◽  
Dental Traits ◽  
South Americans ◽  
Range Of Variation

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.

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