Brief Communication: Human cranial variation fits iterative founder effect model with African origin

Cramon‐Taubadel, Noreen von; Lycett, Stephen J.

doi:10.1002/ajpa.20775

Cited by 95 publications

(159 citation statements)

References 30 publications

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“…[Interestingly, the most divergent and genetically diverse clade was from South Africa, although Linz et al (58) eliminated this as an outlier in some analyses]. Even morphological variation of human crania supports a serial founder effect model OOA (59)(60)(61). In summary, multiple independent lines of genetic evidence thus support a serial founder effect mode of dispersal.…”

Section: Independent Evidence Of Out Of Africa Modelmentioning

confidence: 99%

The great human expansion

Henn

Cavalli-Sforza

Feldman

2012

Proc. Natl. Acad. Sci. U.S.A.

352

232

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Genetic and paleoanthropological evidence is in accord that today's human population is the result of a great demic (demographic and geographic) expansion that began approximately 45,000 to 60,000 y ago in Africa and rapidly resulted in human occupation of almost all of the Earth's habitable regions. Genomic data from contemporary humans suggest that this expansion was accompanied by a continuous loss of genetic diversity, a result of what is called the "serial founder effect." In addition to genomic data, the serial founder effect model is now supported by the genetics of human parasites, morphology, and linguistics. This particular population history gave rise to the two defining features of genetic variation in humans: genomes from the substructured populations of Africa retain an exceptional number of unique variants, and there is a dramatic reduction in genetic diversity within populations living outside of Africa. These two patterns are relevant for medical genetic studies mapping genotypes to phenotypes and for inferring the power of natural selection in human history. It should be appreciated that the initial expansion and subsequent serial founder effect were determined by demographic and sociocultural factors associated with hunter-gatherer populations. How do we reconcile this major demic expansion with the population stability that followed for thousands years until the inventions of agriculture? We review advances in understanding the genetic diversity within Africa and the great human expansion out of Africa and offer hypotheses that can help to establish a more synthetic view of modern human evolution.human population growth | hunter-gatherer demography | molecular evolution

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Section: Independent Evidence Of Out Of Africa Modelmentioning

confidence: 99%

The great human expansion

Henn

Cavalli-Sforza

Feldman

2012

Proc. Natl. Acad. Sci. U.S.A.

352

232

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“…In recent years, the application of a population genetic approach has revealed that neutral evolutionary processes (i.e., drift and migration) can leave a strong signature on human phenotypic traits (e.g., Betti et al, 2009Betti et al, , 2010Weaver 2006a, 2006b;Manica et al 2007;Relethford 1994Relethford , 2002Relethford , 2004Roseman 2004;Roseman andWeaver 2004, 2007;Smith 2009Smith , 2011Strauss and Hubbe 2010;von Cramon-Taubadel and Lycett 2008;von Cramon-Taubadel 2009a, 2009bvon Cramon-Taubadel and Weaver 2009). Cranial shape variation in different human populations, in particular, tends to reflect the underlying neutral genetic pattern, to the point that cranial morphology can be used effectively to test for past demographic events, such as past migrations and the colonization of new regions (e.g., González-José et al 2001, 2002Hubbe et al 2010Hubbe et al , 2011Manica et al 2007;Pinhasi and von Cramon-Taubadel 2009;von Cramon-Taubadel and Pinhasi 2011).…”

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confidence: 99%

Human Pelvis and Long Bones Reveal Differential Preservation of Ancient Population History and Migration Out of Africa

2012

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One of the main events in the history of our species has been our expansion out of Africa. A clear signature of this expansion has been found on global patterns of neutral genetic variation, whereby a serial founder effect accompanied the colonization of new regions, in turn creating a within-population decrease in neutral genetic diversity with increasing distance from Africa. This same distinctive pattern has also been described for cranial and dental morphological variation in human populations distributed across the globe. Here, we used a data set of postcranial linear measurements for 30 globally distributed human populations, and a climatic data set of minimum annual temperature, maximum annual temperature, and precipitation in order to separate for the first time the relative effect of neutral demographic processes and climatic selection on four long (limb) bones (femur, tibia, radius, and humerus) versus the pelvic bones of the human appendicular skeleton. We implemented a stepwise regression procedure in which phenotypic variance is assumed to be affected by the iterative founder events that accompanied human expansion from Africa, as well as by climate. This model included, as independent factors, geographic distance from central Africa, the three climatic variables, and all possible interactions between the three climatic variables. We excluded all nonsignificant factors by backward stepwise elimination with the aim of identifying the minimal model significantly explaining variation in the phenotypic data. Our results indicate a sharp difference in the way the pelvis and the limb bones reflect the neutral signature of the out-of-Africa expansion. Consistent with previous analyses of the cranium and dentition, pelvic shape variation shows a significant within-population decrease with increasing distance from Africa. However, no such pattern could be found in the long bones. Rather, in the case of both the tibia and the femur, a significant relationship between population-level variance and minimum temperature was demonstrated. Hence, in the case of these limb bones, it is probable that the effects of climatic selection have obliterated the demographic signature of human dispersal from Africa. Our finding that pelvic variation exhibits the neutral effects of demographic history suggests that consideration of this skeletal element might be used to shed light on factors of human population history, just as the cranium has done. KeywordsSerial Founder Effect, Out Of Africa, Anatomically Modern Humans, Pelvis Cover Page FootnoteWe are grateful to Brendon Billings of the Medical School of the University of Witwatersrand and Dr. Ogeto Mwebi of the National Museum of Kenya for allowing access to collections and general assistance. We are also especially grateful to Dr. Benjamin Auerbach for generously making his data freely available. We thank Franz Manni and three anonymous reviewers for constructive comments. This study was funded by Sigma Xi, The Abstract One of the main events in the history of our...

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“…In the 2000s, improvements in DNA sequencing technology and genetic sampling of more present day human groups made it possible to accurately characterize the genetic diversity of groups from different regions of the world, and it became clear that within-group genetic diversity decreased predictably with increased geographic distance from subSaharan Africa (3,4). Subsequently, similar, albeit weaker, relationships were found between within-group variation in aspects of skeletal morphology (cranial, dental, and pelvic measurements) and distance from subSaharan Africa (5)(6)(7)(8). These results effectively settled the size vs. time debate, because it was hard to imagine how the observed geographic distribution of within-group diversity could have arisen without a recent range expansion of modern humans from Africa.…”

mentioning

confidence: 98%

Tracing the paths of modern humans from Africa

Weaver

2014

Proc. Natl. Acad. Sci. U.S.A.

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Brief Communication: Human cranial variation fits iterative founder effect model with African origin

Cited by 95 publications

References 30 publications

The great human expansion

The great human expansion

Human Pelvis and Long Bones Reveal Differential Preservation of Ancient Population History and Migration Out of Africa

Tracing the paths of modern humans from Africa

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