why we are not all multiregionalists

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Why we are not all multiregionalistsnow

Chris StringerDepartment of Earth Sciences, The Natural History Museum, London, SW7 5BD, UK

Recent revelations that human genomes contain DNA

introgressed through interbreeding with archaic popula-

tions outside of Africa have led to reassessments of

models for the origins of our species. The fact that small

portions of the DNA of recent Homo sapiens derive from

ancient populations in more than one region of the world

makes our origins multiregional, but does that mean

that the multiregional model of modern human origins

has been proved correct? The extent of archaic assimila-

tion in living humans remains modest, and fossil evi-dence outside of Africa shows little sign of the long-term

morphological continuity through to recent humans

expected from the multiregional model. Thus, rather

than multiregionalism, a recent African origin (RAO)

model for modern humans is still supported by the data.

Multiregional origins?

Recent revelations that human genomes contain DNA

introgressed through interbreeding with archaic popula-

tions outside ofAfrica have led to reassessments of models

for the origins of our species. The fact that small portions of

the DNA of recent Homo sapiens derive from ancient

populations

in

more

than

one

region

of

the

world

makesour origins multiregional, but does that mean that the

multiregional model of modern human origins has been

proved correct? Is it true, as one well-known blogger put it,

that we are all multiregionalists now [1]? Should we,

according to another commentator, stop talking about

evolutionary trees and replace them with braids [2]? More

remarkably, were RAO models, popularly known as Out of

Africa models, founded on a hoax [3]?

Models for modern human origins

First, it is necessary to revisit what the RAO and multire-

gional models stipulate, although this is not straightfor-

ward, because scientists presenting these models have

modified their views in the face of new data, and have

shifted positions.Accepting new data and modifyingviews

are commendable in scientists, of course, but if shifts of

position are not made explicit, confusion will inevitably

follow. In addition, if the shifts are significant, the models

might converge on each other, causing further confusion

[4]. Therefore, I next present models as they were during

the 1990s, as summarised by Aiello [5] and Stringer [4]

(Figure 1):

(i) the RAO model argues that modern humans first

arose in Africa approximately 100 000 years ago and

spread from there throughout the world. Indigenous

premodern populations in other areas of the world

were replaced by the migrating populations, withlittle, if any, hybridisation between the groups

(Figure 1A);

(ii) the RAO and hybridisation model is similar to the

above, but allows for a greater extent of hybridisation

between the migrating population and the indigenous

premodern populations (Figure 1B);

(iii) the assimilation model also accepts an African origin

for modern humans. However, it differs from the

previous models in denying replacement, or popula-

tion migration, as a major process in the appearance

of modern humans. Instead, this model emphasises

the importance of gene flow, admixture, changing

selection

pressures,

and

resulting

directional

mor-phological change (Figure 1C); and

(iv) multiregionalism differs from the previous three in

denying a recentAfrican origin formodern humans. It

emphasises the role of both genetic continuity over

time and gene flow between contemporaneous popu-

lations in arguing that modern humans arose not only

in Africa, but also in Europe and Asia from their

Middle Pleistocene forebears (Figure 1D).

To give a further perspective on these models, I refer the

reader to Figure 2, which compares the models in terms of

the extent of African versus nonAfrican genetic contribu-

tions

to

present-day

humans

worldwide.

On

the

left

ofFigure 2 is absolute RAO (sometimes dubbed by its oppo-

nents the Eve Theory, given that oneversion derived from

mitochondrial DNA (mtDNA) reconstructions of an ances-

tral African Eve), with the total replacement of nonAfri-

can genes.At the other extreme of Figure 2 are models that

give Africa no role in the evolution of modern humans (for

example, ones that have suggested a West Asian or south-

east Asian centre of origin; see [6]). In between the polar

opposites is a mostly out of Africa model in the form of

Brauers [7] RAO + hybridisation, and Smith [8] and Trin-

kauss [9] assimilation model, whereas towards the right is

classic multiregionalism (i.e., the version generally es-

poused from 1984 to 2003, which denied Africa the major

Opinion

0169-5347/$ see front matter

2014 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.tree.2014.03.001

Corresponding author: Stringer, C. ([email protected]).

Keywords: Homo sapiens; human evolution; human origins; modern humans; Africa;

multiregionalism; hybridisation; ancient DNA.

248 Trends in Ecology & Evolution, May 2014, Vol. 29, No. 5
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role in modern human origins [10,11]). Depending on the

extent of nonAfrican archaic gene flow envisaged (less

than, or greater than, 50%), the centrally positioned as-

similation model could approach either RAO + hybridisa-

tion or classic multiregionalism. This is an important

consideration in evaluating theveracity of the assimilation

model, which has tended to argue that modern human

features were assimilated into indigenous populations

outside of Africa, rather than that early modern popula-

tions assimilated elements of the indigenous populations,

as argued by RAO + hybridisation.

An historical perspective on the models

As recently as 1970, no palaeoanthropologist of whom I am

aware held theview thatAfrica was the evolutionary home

of modern humans (as distinct from more ancient species,

such as Homo habilis or Homo erectus). The region was

consideredmarginal or unimportant,with the pendulum of

scientific opinion strongly swung toward nonAfrican, mul-

tiregional, or Neanderthal phase models (the latter postu-

lated that human evolution everywhere had passed

through a Neanderthal-like stage) [6]. However, during

the course of the next two decades, workers such as

Howells [12], Clark [13], Beaumont et al. [14], Hublin

and Tillier [15], Stringer and Day [16], and Brauer [17]

began to focus on Africa as the possible homeland of

modern humans. A convoluted African origin model was

also advanced by Protsch [18], but given that this relied on

dubious self-generated data to argue that modern humans

had originated first, and had then given rise to archaic

humans, it had little influence on the debate (contra Bed-

narik [3]). By the early 1990s, the pendulum was moving in

favour of RAO because fossil evidence began to be increas-

ingly reinforced by the clear signals of mtDNA andY-DNA

in recent human samples. By the late 1990s, the pendulum

had swung even further toward a pure RAO, with growingfossil, archaeological, and genetic data supporting this

model, including the distinctiveness of the first Neander-

thal mtDNA sequences recovered from 1997 onwards [6].

However, large amounts of autosomal DNA have now

been recovered from Eurasian Neanderthals and from

fragmentary fossils found in Denisova Cave, Siberia, re-

vealing another ancient human population. Moreover,

traces of this nonAfrican DNA, attributed to ancient inter-

breeding events, have been found in recent human gen-

omes, indicating that they are not purely of recentAfrican

origin. These revelations have halted and reversed the

pendulum swing, away from an absolute RAO. I would

say

that

we

are

now

looking

at

a

version

of

RAO

that

mostclosely resembles Brauers early formulation (out of Afri-

ca + hybridisation), or perhaps a version of the assimila-

tion model of Smith and Trinkaus, with a strong African

predominance. If the evidence for archaic assimilation in

living humans remains modest and is restricted to Africa

and to the dispersal phase of modern humans from Africa,

constituting less than 10% of our genome, I think mostly

out of Africa is the appropriate designation and, for me,

that is still RAO.

Human species in the fossil record

However, given that interbreeding did occur between mod-

ern and archaic humans, out of Africa and perhaps within

Africa too [19,20], does this mean that we should abandon

the different species names and lump the fossils of the past

million years or more as H. sapiens, as multiregionalists

have suggested? If hybridisation events between the vari-

ous lineages prove to have been widespread and significant

in both time and space, we might have to do that, but I do

not think that point has been reached yet. Personally, I

have never equated the use of a separate species designa-

tion for Neanderthals (morphological species concept) with

complete reproductive isolation from H. sapiens (biological

species concept) and, in my view, there are still good

scientific reasons to give populations that had long and

(largely) separate evolutionary histories different names,

Europe

(A) (B)

(C) (D)

Africa Asia Europe Africa Asia

Europe Africa Asia Europe Africa Asia

TRENDS in Ecology & Evolution

Figure 1. Evolutionarymodelsof modern human origins. (A) Recent African origin;

(B) recent African origin and hybridisation; (C) assimilation; and (D) multiregional

evolution [4,5].

100% RAO RAO+hybridizaon Assimilaon Mulregionalism 0% RAOTRENDS in Ecology & Evolution

Figure 2. A spectrum showing the percentage of recent African genetic

contribution to living humans under various evolutionary scenarios from 0%

recent African origin (RAO) under nonAfrican origin models to 100% under RAO

with complete replacement (see [6]).

Opinion Trends in Ecology & Evolution May 2014, Vol. 29, No. 5

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species or otherwise. We can measure the amount of

morphological variation in closely related primate species

today, and compare this with the differences between, say,

Neanderthals and recent humans (see, for example,

[21,22]). Such comparisons demonstrate that the latter

two are distinct enough to be classed as different species,

regardless of whether they meet the biological species

criterion

of

no

interbreeding

(a

standard

that

numerousrecognised primate species today do not achieve).

If we nevertheless proceed to merge even Neanderthals

and modern humans as a species, we end up with a H.

sapiens that is simultaneously characterised by a high and

rounded skull, and a longer and lower skull; by no contin-

uous brow ridge, and a strong continuous brow ridge; by a

well-developed chin even in infants, and minimal chin

development; by no suprainiac fossa in adults, and a

suprainiac fossa throughout ontogeny; by semicircular

canals of modern shape, and semicircular canals of Nean-

derthal shape; by a narrow pelvis with a short, thick

superior pubic ramus, and a wide pelvis with a long, thin

superiorpubic ramus, and so on.The disparatenature ofH.

sapiens would become even more extreme if we start to addin the features of species such as Homo heidelbergensis ,

antecessor, and erectus. Similar arguments have recently

beenmade in connectionwith theproposal towiden greatly

the diagnosis of H. erectus, based on new fossil discoveries

and analyses from the site of Dmanisi (compare [22] and

[23]).

What the multiregional model really meant

However, if our modern genes do come from more than one

region, why has multiregionalism not been proved correct,

as its supporters are now asserting? At this point, it is

worth reminding ourselves what classic multiregionalism

actually

proposed.

Here

is

a

quotation

from

a

paper

writtenin 1994 by Milford Wolpoff and four other prominent

advocates of the model at that time [10] (note that one

of these authors was Smith, who had by then also proposed

an early version of the assimilation model [8]):

The evolutionary patterns of three different regionsshow that the earliest modern humans are not Afri-cans and do not have the complex of features thatcharacterize the Africans of that time or any other...There is no evidence of specific admixture with Afri-cans at any time, let alone replacement by them...There is indisputable evidence for the continuity ofdistinct unique combinations of skeletal features in

different

regions,

connecting

the

earliest

human

popu-lations with recent and living peoples.

To reinforce that last point, we can add this caption from

Thorne and Wolpoff [11] for archaic and modern human

skulls from China spanning approximately 500 000 years:

Series of Chinese skulls shows continuity in formwithout evidence of a replacement by African char-acteristics.From left to right, themale skulls arefromthe Zhoukoudian Lower Cave (Middle Pleistoceneperiod), Dali site (early Upper Pleistocene period)and Zhoukoudian Upper Cave (late Upper Pleisto-cene).

Thus, multiregionalism gave Africa no special place in

our evolution and claimed specific anatomical connections

down to details of the skull and teeth between H. erectus

fossils that were more than 500 000-years old and humans

living in the same areas today. Despite recent revelations

that support its inference of interregional gene flow (al-

though so far at a relatively low level; see below), the

multiregional model has otherwise been rather compre-

hensively falsified, as has the absolute recent African

origin (Eve theory) model (given that we know that mod-

ernhumans arenotderivedpurely fromAfricanancestors).

Trees and braids

Finlayson [2] has argued that the extent of reticulation

now apparent from genomic data is so great that we should

abandon specific distinctions, and envisage evolutionary

processes as braided rivulets rather than as branches.

However, the view that we should switch to braids and

abandon phylogenetic trees is also mistaken, because we

need both concepts to understand recent human evolution.

As Hawks [24] recognised:

I admit that the braided stream is not a perfectanalogy. Diverging rivulets within a valley almostalways come together again, forming a complicatednetwork as they form sandbars and islets. None ofthemflow into a cul-de-sac.Some humanpopulationsof thepast did becomeextinct, they did not inexorablyflow back into the mainstream of our evolutionaryhistory. Some of them may have flowed back into themainstream only through very small channels of ge-netic exchange. When we go far enough back, somepopulations really did branch off into their own di-rection.

Comparing 1000 recent human genomes reveals ap-

proximately 100 changes in amino acid coding shared by

living H. sapiens but absent from the Neanderthal and

Denisovan genomes [25], including ones that are known to

influence the development and maintenance of brain cells.

Over 3000 further genetic mutations that might have

affected the behavioural or morphological evolution of

modern humans are also uniquely fixed in our species.

Such distinctions are likely to have accumulated during

the several hundred millennia that the lineages of H.

sapiens and those of Neanderthals and Denisovans were

biogeographically separated (tree concept), and evidently

did

not

diffuse

into

the

genomes

of

Neanderthals

andDenisovans known so far, despite any braids of gene flow

that might have existed. This brings us on to a fundamen-

tal issue: does the relatively low prevalence of Neanderthal

and Denisovan genes in H. sapiens reflect the rarity of

ancient hybridisation opportunities, or their lack of viabil-

ity [26]? Whereas multiregional and assimilation models

often imply unconstrained interbreeding between ancient

human groups whenever they had the opportunity, the

reality is that many factors (demographic, cultural, and

biological) could have militated against reproductive suc-

cess, and we are now learning more about these con-

straints, including the fact that exchanges between

genetically distant populations can have costs as well as


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benefits [27,28]. New analyses suggest that, when modern

humans and Neanderthals met and mixed, they were at

the edge of biological incompatibility, such that there was

reduced male fertility and rapid natural selection to re-

move the Neanderthal-derived variants that caused this

sterility [27]. Further evidence of the swift elimination of

much of the introgressed DNA comes from the partial

genome

of

the

Tianyuan

skeleton

from

China,

dated

toapproximately 40 000 years ago, because this shows a no

greater component of Neanderthal-derived DNA than re-

cent Asian samples [29].

RAO is still the most appropriate model

The big picture is that we are predominantly of recent

African origin, and RAO is not just about the sources of our

shared modern morphology andmost of our genes; it is also

about the genesis of our shared patterns of behaviour.

Inferred behavioural gapsbetweenNeanderthals andmod-

ern humans have certainly narrowed from recent research,

but in myview they have not disappeared. I think that the

pre-eminence of Africa in the story of modern human

origins was primarily a question of its larger geographicand human population size, which gave greater opportu-

nities formorphological andbehavioural variations, and for

innovations to develop and be conserved, rather than the

result of a special evolutionary pathway. By contrast,

genomicdata suggest that the lineagesof theNeanderthals

and Denisovans had much greater demographic attrition

[25], perhaps related to the challenges posed by the unsta-

ble climates of Eurasia, and thismight well have inhibited

their cultural as well as physical evolution [6].

Modernity was not a package that had a single African

origin in one time, place, andpopulation,butwas a compos-

ite whose elements appeared, and sometimes disappeared,

at

different

times and places

and then coalesced to

assumethe form we see in extant humans [6]. However, during the

past 400 000 years, most of that assembly took place in

Africa, which is why a recent African origin still represents

thepredominant (butnotexclusive)mode of evolution forH.

sapiens. Rather than saying we are all multiregionalists

trying to explain the out-of-Africa pattern [1], it would be

more appropriate to say we are all out-of-Africanists who

accept some multiregional contributions.

Acknowledgements

I would like to thank David Reich, Laura Buck, and two reviewers for

their helpful comments on this manuscript, and the Human Origins

Research Fund and the Calleva Foundation for support of my research.

References1 Hawks, J. (2010) Neandertals Live! (http://johnhawks.net/weblog/

reviews/neandertals/neandertal_dna/neandertals-live-genome-

sequencing-2010.html) [Accessed 10 March 2014]

2 Finlayson, C. (2013)Viewpoint: Human Evolution, from Tree to Braid.

(http://www.bbc.co.uk/news/science-environment-25559172#)

[Accessed 10 March 2014]

3 Bednarik,R. (2013)AfricanEve: hoax orhypothesis?Adv. Anthropol.3,

216228

4 Stringer, C. (2002) Modern human origins progress and prospects.

Philos. Trans. R. Soc. Lond. B: Biol. Sci. 357, 563579

5 Aiello, L.C. (1993) The fossil evidence for modern human origins in

Africa: a revised view. Am. Anthropol. 95, 7396

6 Stringer,C. (2012)TheOriginof OurSpecies, Penguin(publishedin the

USA asLone Survivors: HowWe Came to be theOnlyHumanson Earth

by Times Books)

7 Brauer, G. (1992) Africas place in the evolution ofHomo sapiens. In

Continuity or Replacement? Controversies in Homo sapiens Evolution

(Brauer, G. and Smith, F., eds), pp. 8398, Balkema8 Smith, F. (1992) The role of continuity in modern human origins. In

Continuity or Replacement? Controversies in Homo sapiens Evolution

(Brauer, G. and Smith, F., eds), pp. 145156, Balkema

9 Trinkaus, E. (2005) Early modern humans. Annu. Rev. Anthropol. 34,

207230

10 Wolpoff, M.H. et al. (1994) Multiregional evolution: a world-wide

source for modern human populations. In Origins of Anatomically

Modern Humans (Nitecki, M.H. andNitecki, D.V., eds), pp. 175199,

Plenum

11 Thorne, A.G. andWolpoff, M.H. (2003) The multiregional evolution of

humans (revised paper). Sci. Am. 13, 4653

12 Howells, W.W. (1973) Evolution of the Genus Homo, Addison-Wesley

Longman

13 Clark, D. (1975) Africa in prehistory: peripheral or paramount? Man

10, 175198

14

Beaumont, P.B.et al. (1978)Modernman in sub-Saharan Africa priorto 49,000 years B.P.: a reviewandevaluation with particular reference

to Border Cave. S. Afr. J. Sci. 74, 409419

15 Hublin, J-J. and Tillier, A.M. (1981) The Mousterian juvenile

mandible from Irhoud (Morocco): a phylogenetic interpretation. In

Aspects of Human Evolution (Stringer,C.B., ed.), pp. 167185, Taylor

& Francis

16 Day, M. and Stringer, C.B. (October, 1982) A reconsideration of the

Omo Kibish remains and the erectussapiens transition. In Pretirage

First International Congress of Human Palaeontology. pp. 814846,

Nice, CNRS

17 Brauer,G. (1984) The Afro-Europeansapiens hypothesis andhominid

evolution in east Asia during theMiddle andUpper Pleistocene.Cour.

Forsch. Senck. 69, 145165

18 Protsch, R. (1975) The absolute dating of Upper Pleistocene sub-

Saharan fossil hominids and their place in human evolution.

J. Hum. Evol. 4, 297322

19 Hammer, M. et al. (2011) Genetic evidence for archaic admixture in

Africa. Proc. Natl. Acad. Sci. U.S.A. 108, 1512315128

20 Harvati, K.et al. (2011) The Later Stone Age calvaria from Iwo Eleru,

Nigeria: morphology and chronology. PLoS ONE 6, e24024

21 Harvati, K. et al. (2004) Neanderthal taxonomy reconsidered:

implications of 3D primate models of intra- and interspecific

differences. Proc. Natl.Acad. Sci. U.S.A. 101, 11471152

22 Lordkipanidze,D.et al. (2013)A complete skull fromDmanisi,Georgia,

and the evolutionary biology of earlyHomo. Science 342, 326331

23 Hublin, J-J. (2014) Paleoanthropology:Homo erectus and thelimits ofa

paleontological species. Curr. Biol. 24, R82R84

24 Hawks,J. (2013)The BaidedSreamatYear-end. (http://johnhawks.net/

weblog/topics/news/finlayson-braided-stream-2013.html) [Accessed 10

March 2014]

25 Pru fer, K.et al. (2014) The complete genome sequence of aNeanderthal

from the Altai Mountains. Nature 505, 4349

26 Currat, M. and Excoffier, L. (2011) Strong reproductive isolation

between humans and Neanderthals inferred from observed patterns

of introgression. Proc. Natl. Acad. Sci. U.S.A. 108, 1512915132

27 Sankararaman, S.et al. (2014)The landscapeofNeandertalancestry in

present-day humans.Nature http://dx.doi.org/10.1038/nature12961

28 Vernot, B. and Akey, J.M. (2014) Resurrecting surviving Neandertal

lineages from modern human genomes. Science http://dx.doi.org/

10.1126/science.1245938

29 Fu, Q. et al. (2013) DNA analysis of an early modern human from

Tianyuan Cave, China.Proc. Natl. Acad. Sci. U.S.A. 10, 22232227


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hub.elsevier.com/S0169-5347(14)00047-0/sbref0110http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0110http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0110http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0115http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0115http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0115http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0115http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0115http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0115http://johnhawks.net/weblog/topics/news/finlayson-braided-stream-2013.htmlhttp://johnhawks.net/weblog/topics/news/finlayson-braided-stream-2013.htmlhttp://johnhawks.net/weblog/topics/news/finlayson-braided-stream-2013.htmlhttp://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0130http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0130http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0130http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0130http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0130http://dx.doi.org/10.1038/nature12961http://dx.doi.org/10.1126/science.1245938http://dx.doi.org/10.1126/science.1245938http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0145http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0145http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0145http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0145http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0145http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0145http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0145http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0145http://dx.doi.org/10.1126/science.1245938http://dx.doi.org/10.1126/science.1245938http://dx.doi.org/10.1038/nature12961http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0130http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0130http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0130http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0125http://johnhawks.net/weblog/topics/news/finlayson-braided-stream-2013.htmlhttp://johnhawks.net/weblog/topics/news/finlayson-braided-stream-2013.htmlhttp://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0115http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0115http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0110http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0110http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0105http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0105http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0105http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0100http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0100http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0095http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0095http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0090http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0090http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0090http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0085http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0085http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0085http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0080http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0080http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0080http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0080http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0075http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0075http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0075http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0075http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0070http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0070http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0070http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0065http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0065http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0060http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0060http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0055http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0055http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0050http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0050http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0050http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0050http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0045http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0045http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0040http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0040http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0040http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0035http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0035http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0035http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0030http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0030http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0030http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0025http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0025http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0020http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0020http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0015http://refhub.elsevier.com/S0169-5347(14)00047-0/sbref0015http://www.bbc.co.uk/news/science-environment-25559172http://johnhawks.net/weblog/reviews/neandertals/neandertal_dna/neandertals-live-genome-sequencing-2010.htmlhttp://johnhawks.net/weblog/reviews/neandertals/neandertal_dna/neandertals-live-genome-sequencing-2010.htmlhttp://johnhawks.net/weblog/reviews/neandertals/neandertal_dna/neandertals-live-genome-sequencing-2010.html

why we are not all multiregionalists

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