16. Major transitions in human
evolution
• Bipedalism (down from the trees)
In which order?
17. Major transitions in human
evolution
• Bipedalism (down from the trees)
• Increased brain size
In which order?
18. Major transitions in human
evolution
• Bipedalism (down from the trees)
• Increased brain size
In which order?
• Use of simple stone tools
19. Major transitions in human
evolution
• Bipedalism (down from the trees)
• Increased brain size
In which order?
• Use of simple stone tools
• Fire
20. Major transitions in human
evolution
• Bipedalism (down from the trees)
• Increased brain size
In which order?
• Use of simple stone tools
• Fire
• Sophisticated tools (stone, bone...)
21. Major transitions in human
evolution
• Bipedalism (down from the trees)
• Increased brain size
In which order?
• Use of simple stone tools
• Fire
• Sophisticated tools (stone, bone...)
• Language, culture, agriculture...
54. Evidence for bipedalism in Australopithecines
• Pelvis short & broad (like humans), not long & narrow (like gorilla)
55. Evidence for bipedalism in Australopithecines
• Pelvis
short & broad (like humans), not long & narrow (like gorilla)
• Hip & walking muscles arranged like in a bipedal organism
56. Evidence for bipedalism in Australopithecines
• Pelvis
short & broad (like humans), not long & narrow (like gorilla)
• Hip & walking muscles arranged like in a bipedal organism
• Femur angled as in humans, not straight as in chimps
57. Evidence for bipedalism in Australopithecines
• Pelvis
short & broad (like humans), not long & narrow (like gorilla)
• Hip & walking muscles arranged like in a bipedal organism
• Femur angled as in humans, not straight as in chimps
• Feet
58. Fossilized tracks at
Laetoli (Tanzania)
Footprints preserved in
volcanic ash from: 3 hominids
(Australopithecus afarensis)
Numerous other mammals
59. Fossilized tracks at
Laetoli (Tanzania)
Footprints preserved in
volcanic ash from: 3 hominids
(Australopithecus afarensis)
Numerous other mammals
62. Tool use?
• generally: only simple tools (similarly to current non-human
great apes).
• butAustralopithecus garhi (2.5 mya) may have made stone
tools.
96. Neanderthals - Summary
• Neanderthals were morphologically and genetically distinct
from early H. sapiens
• disappearedafter H. sapiens arrived - possibly because they
were culturally less advanced.
97. H. neanderthalensis
H. sapiens
H. erectus
Australopithecines
Proconsulidae Most lineages
went extinct
99. H. sapiens out of Africa
• 50,000 years ago: fully “modern” with language, music etc.
100. H. sapiens out of Africa
• 50,000 years ago: fully “modern” with language, music etc.
• Began migrating out of Africa 70,000 years ago
101. H. sapiens out of Africa
• 50,000 years ago: fully “modern” with language, music etc.
• Began migrating out of Africa 70,000 years ago
• Simultaneous decline of other Homo species (competition or
hybridization?)
102.
103. Burial ritual in
early H. sapiens
• At Sungir, Russia, around 28,000
years ago
• A 60 year old buried with an
elaborate collection of beads,
necklaces and bracelets
108. RESEARCH ARTICLE
changed parts of their genome with the ances-
tors of these groups.
A Draft Sequence of the
Several features of DNA extracted from Late
Pleistocene remains make its study challenging.
The DNA is invariably degraded to a small aver-
Neandertal Genome age size of less than 200 base pairs (bp) (21, 22),
it is chemically modified (21, 23–26), and extracts
Richard E. Green,1*†‡ Johannes Krause,1†§ Adrian W. Briggs,1†§ Tomislav Maricic,1†§
almost always contain only small amounts of en-
Udo Stenzel,1†§ Martin Kircher,1†§ Nick Patterson,2†§ Heng Li,2† Weiwei Zhai,3†||
dogenous DNA but large amounts of DNA from
Markus Hsi-Yang Fritz,4† Nancy F. Hansen,5† Eric Y. Durand,3† Anna-Sapfo Malaspinas,3†
microbial organisms that colonized the specimens
Jeffrey D. Jensen,6† Tomas Marques-Bonet,7,13† Can Alkan,7† Kay Prüfer,1† Matthias Meyer,1†
after death. Over the past 20 years, methods for
Hernán A. Burbano,1† Jeffrey M. Good,1,8† Rigo Schultz,1 Ayinuer Aximu-Petri,1 Anne Butthof,1
ancient DNA retrieval have been developed (21, 22),
Barbara Höber,1 Barbara Höffner,1 Madlen Siegemund,1 Antje Weihmann,1 Chad Nusbaum,2
largely based on the polymerase chain reaction
Eric S. Lander,2 Carsten Russ,2 Nathaniel Novod,2 Jason Affourtit,9 Michael Egholm,9
(PCR) (27). In the case of the nuclear genome of
Christine Verna,21 Pavao Rudan,10 Dejana Brajkovic,11 Željko Kucan,10 Ivan Gušic,10
Neandertals, four short gene sequences have been
Vladimir B. Doronichev,12 Liubov V. Golovanova,12 Carles Lalueza-Fox,13 Marco de la Rasilla,14
determined by PCR: fragments of the MC1R gene
Javier Fortea,14 ¶ Antonio Rosas,15 Ralf W. Schmitz,16,17 Philip L. F. Johnson,18† Evan E. Eichler,7†
involved in skin pigmentation (28), a segment of
Daniel Falush,19† Ewan Birney,4† James C. Mullikin,5† Montgomery Slatkin,3† Rasmus Nielsen,3†
the FOXP2 gene involved in speech and language
loaded from www.sciencemag.org on March 24, 2013
Janet Kelso,1† Michael Lachmann,1† David Reich,2,20*† Svante Pääbo1*†
(29), parts of the ABO blood group locus (30), and
a taste receptor gene (31). However, although PCR
Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe of ancient DNA can be multiplexed (32), it does
and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal not allow the retrieval of a large proportion of the
genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the genome of an organism.
Neandertal genome to the genomes of five present-day humans from different parts of the world The development of high-throughput DNA se-
identify a number of genomic regions that may have been affected by positive selection in ancestral quencing technologies (33, 34) allows large-scale,
modern humans, including genes involved in metabolism and in cognitive and skeletal development. genome-wide sequencing of random pieces of
We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with DNA extracted from ancient specimens (35–37)
present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the and has recently made it feasible to sequence ge-
ancestors of non-Africans occurred before the divergence of Eurasian groups from each other. 1
Department of Evolutionary Genetics, Max-Planck Institute for
T
Evolutionary Anthropology, D-04103 Leipzig, Germany. 2Broad
he morphological features typical of Nean- sumed ancestors of present-day Europeans. Institute of MIT and Harvard, Cambridge, MA 02142, USA.
dertals first appear in the European fossil Similarly, analysis of DNA sequence data from 3
Department of Integrative Biology, University of California,
record about 400,000 years ago (1–3). present-day humans has been interpreted as evi- Berkeley, CA 94720, USA. 4European Molecular Biology
Progressively more distinctive Neandertal forms dence both for (12, 13) and against (14) a genetic Laboratory–European Bioinformatics Institute, Wellcome Trust
Genome Campus, Hinxton, Cambridgeshire, CB10 1SD, UK.
subsequently evolved until Neandertals disap- contribution by Neandertals to present-day hu- 5
Genome Technology Branch, National Human Genome Re-
peared from the fossil record about 30,000 years mans. The only part of the genome that has been search Institute, National Institutes of Health, Bethesda, MD
ago (4). During the later part of their history, examined from multiple Neandertals, the mito- 20892, USA. 6Program in Bioinformatics and Integrative Biology,
Neandertals lived in Europe and Western Asia chondrial DNA (mtDNA) genome, consistently University of Massachusetts Medical School, Worcester, MA
01655, USA. 7Howard Hughes Medical Institute, Department
as far east as Southern Siberia (5) and as far falls outside the variation found in present-day
of Genome Sciences, University of Washington, Seattle, WA
south as the Middle East. During that time, Nean- humans and thus provides no evidence for inter- 98195, USA. 8Division of Biological Sciences, University of
109. RESEARCH ARTICLE
changed parts of their genome with the ances-
tors of these groups.
A Draft Sequence of the
Several features of DNA extracted from Late
Pleistocene remains make its study challenging.
The DNA is invariably degraded to a small aver-
Neandertal Genome age size of less than 200 base pairs (bp) (21, 22),
it is chemically modified (21, 23–26), and extracts
Richard E. Green,1*†‡ Johannes Krause,1†§ Adrian W. Briggs,1†§ Tomislav Maricic,1†§
almost always contain only small amounts of en-
Udo Stenzel,1†§ Martin Kircher,1†§ Nick Patterson,2†§ Heng Li,2† Weiwei Zhai,3†||
dogenous DNA but large amounts of DNA from
Markus Hsi-Yang Fritz,4† Nancy F. Hansen,5† Eric Y. Durand,3† Anna-Sapfo Malaspinas,3†
microbial organisms that colonized the specimens
Jeffrey D. Jensen,6† Tomas Marques-Bonet,7,13† Can Alkan,7† Kay Prüfer,1† Matthias Meyer,1†
after death. Over the past 20 years, methods for
Hernán A. Burbano,1† Jeffrey M. Good,1,8† Rigo Schultz,1 Ayinuer Aximu-Petri,1 Anne Butthof,1
ancient DNA retrieval have been developed (21, 22),
Barbara Höber,1 Barbara Höffner,1 Madlen Siegemund,1 Antje Weihmann,1 Chad Nusbaum,2
largely based on the polymerase chain reaction
Eric S. Lander,2 Carsten Russ,2 Nathaniel Novod,2 Jason Affourtit,9 Michael Egholm,9
(PCR) (27). In the case of the nuclear genome of
Christine Verna,21 Pavao Rudan,10 Dejana Brajkovic,11 Željko Kucan,10 Ivan Gušic,10
Neandertals, four short gene sequences have been
Vladimir B. Doronichev,12 Liubov V. Golovanova,12 Carles Lalueza-Fox,13 Marco de la Rasilla,14
determined by PCR: fragments of the MC1R gene
Javier Fortea,14 ¶ Antonio Rosas,15 Ralf W. Schmitz,16,17 Philip L. F. Johnson,18† Evan E. Eichler,7†
involved in skin pigmentation (28), a segment of
Daniel Falush,19† Ewan Birney,4† James C. Mullikin,5† Montgomery Slatkin,3† Rasmus Nielsen,3†
the FOXP2 gene involved in speech and language
loaded from www.sciencemag.org on March 24, 2013
Janet Kelso,1† Michael Lachmann,1† David Reich,2,20*† Svante Pääbo1*†
(29), parts of the ABO blood group locus (30), and
a taste receptor gene (31). However, although PCR
Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe of ancient DNA can be multiplexed (32), it does
and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal not allow the retrieval of a large proportion of the
genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the genome of an organism.
Neandertal genome to the genomes of five present-day humans from different parts of the world The development of high-throughput DNA se-
identify a number of genomic regions that may have been affected by positive selection in ancestral quencing technologies (33, 34) allows large-scale,
modern humans, including genes involved in metabolism and in cognitive and skeletal development. genome-wide sequencing of random pieces of
We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with DNA extracted from ancient specimens (35–37)
present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the and has recently made it feasible to sequence ge-
ancestors of non-Africans occurred before the divergence of Eurasian groups from each other. 1
Department of Evolutionary Genetics, Max-Planck Institute for
T
Evolutionary Anthropology, D-04103 Leipzig, Germany. 2Broad
he morphological features typical of Nean- sumed ancestors of present-day Europeans. Institute of MIT and Harvard, Cambridge, MA 02142, USA.
dertals first appear in the European fossil Similarly, analysis of DNA sequence data from 3
Department of Integrative Biology, University of California,
record about 400,000 years ago (1–3). present-day humans has been interpreted as evi- Berkeley, CA 94720, USA. 4European Molecular Biology
Progressively more distinctive Neandertal forms dence both for (12, 13) and against (14) a genetic Laboratory–European Bioinformatics Institute, Wellcome Trust
Genome Campus, Hinxton, Cambridgeshire, CB10 1SD, UK.
subsequently evolved until Neandertals disap- contribution by Neandertals to present-day hu- 5
Genome Technology Branch, National Human Genome Re-
peared from the fossil record about 30,000 years mans. The only part of the genome that has been
2-4% of eurasian DNA comes from Neanderthals
search Institute, National Institutes of Health, Bethesda, MD
ago (4). During the later part of their history, examined from multiple Neandertals, the mito- 20892, USA. 6Program in Bioinformatics and Integrative Biology,
Neandertals lived in Europe and Western Asia chondrial DNA (mtDNA) genome, consistently University of Massachusetts Medical School, Worcester, MA
01655, USA. 7Howard Hughes Medical Institute, Department
as far east as Southern Siberia (5) and as far falls outside the variation found in present-day
of Genome Sciences, University of Washington, Seattle, WA
south as the Middle East. During that time, Nean- humans and thus provides no evidence for inter- 98195, USA. 8Division of Biological Sciences, University of
110. RESEARCH ARTICLE
changed parts of their genome with the ances-
tors of these groups.
A Draft Sequence of the
Several features of DNA extracted from Late
Pleistocene remains make its study challenging.
The DNA is invariably degraded to a small aver-
Neandertal Genome age size of less than 200 base pairs (bp) (21, 22),
it is chemically modified (21, 23–26), and extracts
Richard E. Green,1*†‡ Johannes Krause,1†§ Adrian W. Briggs,1†§ Tomislav Maricic,1†§
almost always contain only small amounts of en-
Udo Stenzel,1†§ Martin Kircher,1†§ Nick Patterson,2†§ Heng Li,2† Weiwei Zhai,3†||
dogenous DNA but large amounts of DNA from
Markus Hsi-Yang Fritz,4† Nancy F. Hansen,5† Eric Y. Durand,3† Anna-Sapfo Malaspinas,3†
microbial organisms that colonized the specimens
Jeffrey D. Jensen,6† Tomas Marques-Bonet,7,13† Can Alkan,7† Kay Prüfer,1† Matthias Meyer,1†
after death. Over the past 20 years, methods for
Hernán A. Burbano,1† Jeffrey M. Good,1,8† Rigo Schultz,1 Ayinuer Aximu-Petri,1 Anne Butthof,1
ancient DNA retrieval have been developed (21, 22),
Barbara Höber,1 Barbara Höffner,1 Madlen Siegemund,1 Antje Weihmann,1 Chad Nusbaum,2
largely based on the polymerase chain reaction
Eric S. Lander,2 Carsten Russ,2 Nathaniel Novod,2 Jason Affourtit,9 Michael Egholm,9
(PCR) (27). In the case of the nuclear genome of
Christine Verna,21 Pavao Rudan,10 Dejana Brajkovic,11 Željko Kucan,10 Ivan Gušic,10
Neandertals, four short gene sequences have been
Vladimir B. Doronichev,12 Liubov V. Golovanova,12 Carles Lalueza-Fox,13 Marco de la Rasilla,14
determined by PCR: fragments of the MC1R gene
Javier Fortea,14 ¶ Antonio Rosas,15 Ralf W. Schmitz,16,17 Philip L. F. Johnson,18† Evan E. Eichler,7†
involved in skin pigmentation (28), a segment of
Daniel Falush,19† Ewan Birney,4† James C. Mullikin,5† Montgomery Slatkin,3† Rasmus Nielsen,3†
the FOXP2 gene involved in speech and language
loaded from www.sciencemag.org on March 24, 2013
Janet Kelso,1† Michael Lachmann,1† David Reich,2,20*† Svante Pääbo1*†
(29), parts of the ABO blood group locus (30), and
a taste receptor gene (31). However, although PCR
Neandertals, the closest evolutionary relatives of present-day humans, lived in large parts of Europe of ancient DNA can be multiplexed (32), it does
and western Asia before disappearing 30,000 years ago. We present a draft sequence of the Neandertal not allow the retrieval of a large proportion of the
genome composed of more than 4 billion nucleotides from three individuals. Comparisons of the genome of an organism.
Neandertal genome to the genomes of five present-day humans from different parts of the world The development of high-throughput DNA se-
identify a number of genomic regions that may have been affected by positive selection in ancestral quencing technologies (33, 34) allows large-scale,
modern humans, including genes involved in metabolism and in cognitive and skeletal development. genome-wide sequencing of random pieces of
We show that Neandertals shared more genetic variants with present-day humans in Eurasia than with DNA extracted from ancient specimens (35–37)
present-day humans in sub-Saharan Africa, suggesting that gene flow from Neandertals into the and has recently made it feasible to sequence ge-
ancestors of non-Africans occurred before the divergence of Eurasian groups from each other. 1
Department of Evolutionary Genetics, Max-Planck Institute for
T
Evolutionary Anthropology, D-04103 Leipzig, Germany. 2Broad
he morphological features typical of Nean- sumed ancestors of present-day Europeans. Institute of MIT and Harvard, Cambridge, MA 02142, USA.
dertals first appear in the European fossil Similarly, analysis of DNA sequence data from 3
Department of Integrative Biology, University of California,
record about 400,000 years ago (1–3). present-day humans has been interpreted as evi- Berkeley, CA 94720, USA. 4European Molecular Biology
Progressively more distinctive Neandertal forms dence both for (12, 13) and against (14) a genetic Laboratory–European Bioinformatics Institute, Wellcome Trust
Genome Campus, Hinxton, Cambridgeshire, CB10 1SD, UK.
subsequently evolved until Neandertals disap- contribution by Neandertals to present-day hu- 5
Genome Technology Branch, National Human Genome Re-
peared from the fossil record about 30,000 years mans. The only part of the genome that has been
2-4% of eurasian DNA comes from Neanderthals
search Institute, National Institutes of Health, Bethesda, MD
ago (4). During the later part of their history, examined from multiple Neandertals, the mito- 20892, USA. 6Program in Bioinformatics and Integrative Biology,
Neandertals lived in Europe and Western Asia chondrial DNA (mtDNA) genome, consistently University of Massachusetts Medical School, Worcester, MA
01655, USA. 7Howard Hughes Medical Institute, Department
as far east as Southern Siberia (5) and as far falls outside the variation found in present-day
of Genome Sciences, University of Washington, Seattle, WA
south as the Middle East. During that time, Nean- humans and thus provides no evidence for inter- 98195, USA. 8Division of Biological Sciences, University of
111. Strong reproductive isolation between human
Strong reproductive isolation between humans
and Neanderthals inferred from observed
Neanderthals inferred from observed
patterns of introgression
patterns of introgression
Mathias Currata,1 and Laurent Excoffierb,c,1
Mathias Currata,1 and Laurent Excoffierb,c,1
a
a Anthropology,
Anthropology, Genetics, and Peopling History Laboratory, Anthropology Unit, Department of of Genetics and Evolution, University G
Genetics, and Peopling History Laboratory, Anthropology Unit, Department Genetics and Evolution, University of o
1227 Geneva, Switzerland; bComputational and Molecular Population Genetics Laboratory, Institute Ecology and Evolution, Univers
1227 Geneva, Switzerland; bComputational and Molecular Population Genetics Laboratory, Institute of of Ecology and Evolution, Uni
3012 Berne, Switzerland; and cSwiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
3012 Berne, Switzerland; and cSwiss Institute of Bioinformatics, 1015 Lausanne, Switzerland
Edited by Svante Pääbo, Max Planck Institute of Evolutionary Anthropology, Leipzig, Germany, and approved August 3, 2011 (rece
Edited by Svante Pääbo, Max Planck Institute of Evolutionary Anthropology, Leipzig, Germany, and approved August 3, 2011 (receive
May 10, 2011)
May 10, 2011)
Recent studies have revealed that 2–3% of the genome of non-
Recent studies have revealed that 2–3% of the genome of non- To examine these issues and clarify the proce
To examine these issues and clarify the pro
Africans might come from Neanderthals, suggesting a a more complex
Africans might come from Neanderthals, suggesting more complex between Neanderthals and modern humans, we
between Neanderthals and modern humans,
scenario of modern human evolution than previously anticipated. InIn
scenario of modern human evolution than previously anticipated. istic and spatially explicit model of of admixt
istic and spatially explicit model admixture
this paper, we use a model of admixture during a a spatial expansion
this paper, we use a model of admixture during spatial expansion between modern humans and Neanderthals (3
between modern humans and Neanderthals
to study the hybridization of Neanderthals with modern humans
to study the hybridization of Neanderthals with modern humans simulations, we have estimated the interbree
simulations, we have estimated the interb
during their spread out of Africa. We find that observed low levels
during their spread out of Africa. We find that observed low levels between humans and Neanderthals as as well t
between humans and Neanderthals well as a
of Neanderthal ancestry in Eurasians are compatible with a a very low
of Neanderthal ancestry in Eurasians are compatible with very low hybridization that is is compatible with the o
hybridization that compatible with the obs
rate of interbreeding (<2%), potentially attributable to a a very strong
rate of interbreeding (<2%), potentially attributable to very strong Neanderthal ancestry in in contemporary huma
Neanderthal ancestry contemporary humans,
avoidance of interspecific matings, aa low fitness of hybrids, or both.
avoidance of interspecific matings, low fitness of hybrids, or both. latter migrated out of of Africa into Eurasia 50
latter migrated out Africa into Eurasia 50 ky
These results suggesting the presence of very effective barriers toto
These results suggesting the presence of very effective barriers
gene flow between the two species are robust to uncertainties about
gene flow between the two species are robust to uncertainties about Results
Results
the exact demography of the Paleolithic populations, and they are Low Rates of of Interbreeding Between Huma
the exact demography of the Paleolithic populations, and they are Low Rates Interbreeding Between Humans
also found to be compatible with the observed lack of mtDNA in- Using spatially explicit simulations, wewe
also found to be compatible with the observed lack of mtDNA in-
trogression. Our model additionally suggests that similarly low levels
Using spatially explicit simulations, hav
trogression. Our model additionally suggests that similarly low levels expected amount of of Neanderthal ancestry pr
expected amount Neanderthal ancestry in in
of introgression in Europe and Asia may result from distinct admix-
of introgression in Europe and Asia may result from distinct admix- from Europe (France) and Asia (China) forfo
ture events having occurred beyond the Middle East, after the split ofof from Europe (France) and Asia (China)
ture events having occurred beyond the Middle East, after the split admixture with Neanderthals and over variou
admixture with Neanderthals and over var
Europeans and Asians. This hypothesis could be tested because it it derthal ranges (Fig. 1).1). Under our model
Europeans and Asians. This hypothesis could be tested because
predicts that different components of Neanderthal ancestry should derthal ranges (Fig. Under our model of
predicts that different components of Neanderthal ancestry should range expansion, we find that observed low leve
range expansion, we find that observed low l
be present in Europeans and in Asians.
be present in Europeans and in Asians. introgression into Eurasians imply the existe
113. Denisovans
• Only
known remains(all found since 2010): phalanx (finger
bone), three teeth, a toe bone. From 41,000 years ago.
114. Denisovans
• Only
known remains(all found since 2010): phalanx (finger
bone), three teeth, a toe bone. From 41,000 years ago.
• Amazinglywell preserved DNA (Siberia; average temperature
0°C). sequenced the genome.
115. Denisovans
• Only
known remains(all found since 2010): phalanx (finger
bone), three teeth, a toe bone. From 41,000 years ago.
• Amazinglywell preserved DNA (Siberia; average temperature
0°C). sequenced the genome.
• Common ancestor with Neanderthal: 600,000 years ago
116. Denisovans
• Only
known remains(all found since 2010): phalanx (finger
bone), three teeth, a toe bone. From 41,000 years ago.
• Amazingly well preserved DNA (Siberia; average temperature
0°C). sequenced the genome.
• Common ancestor with Neanderthal: 600,000 years ago
• Interbreeding
with Homo sapiens: 4-6% of Melanesian
genomes are from Denisovan.
117. H. neanderthalensis
H. sapiens
H. erectus
Australopithecines
Proconsulidae Most lineages
went extinct
118. H. neanderthalensis
H. sapiens
Denisovan
H. erectus
Australopithecines
Proconsulidae Most lineages
went extinct
119. Stoneking & Krause 2011
? No admixture detected despite probable overlap
! detected admixture (location uncertain)
African ori
of mtDNA
lations have
of our spec
the deepest
sity 14,62–65. G
view 7–9, and
humans ind
within mod
from south
mately 115
humans fir
divergences
35–50 kya13
of a strong
our genome
close correla
Stoneking & Krause 2011 in a populat
ulation from
120. A WINDING PATH H. sapiens spread from Africa to
After early modern humans left Africa around 60,000 years ago (top
western Asia and then to Europe and
right), they spread across the globe and interbred with other southern Asia, eventually reaching
descendants of Homo heidelbergensis. Australasia and the Americas.
0
Homo sapiens
Homo floresiensis Denisovans Neanderthals
Homo erectus
0.4
Homo heidelbergensis
Million years ago
0.8
Homo antecessor
H. heidelbergensis
originated from
1.2 H. erectus in an
unknown location
and dispersed across
Homo erectus Africa, southern Asia
and southern Europe.
1.6
H. floresiensis originated H. erectus spread to western Asia, then
in an unknown location east Asia and Indonesia. Its presence
and reached remote in Europe is uncertain, but it gave rise
2.0 parts of Indonesia. to H. antecessor, found in Spain.
Wavy branch edges suggest presumed fluctuations in population.
PATCHWORK PLANET
Most people’s genomes contain remnants of archaic DNA from ancient interbreeding3–6.
2% 2.5% 2.5% 5% Genes*
African
Unknown archaic
African source
98% 97.5% 92.5% Neanderthal
Denisovan
Stringer 2012
*Figures are approximate,
and for Africa, based on
limited data6.
Sub-Saharan Africa Eurasia and Americas Australia and New Guinea
121. REPORTS
Deep Human Genealogies Reveal a tracing back the founding events of new localities.
As shown in Fig. 1, the inferred colonization pro-
cess is a mixture of long-distance settlements
Selective Advantage to Be on an creating an irregular wave front, followed by fur-
ther, more progressive, short-range expansions,
Expanding Wave Front which then filled gaps and created a more reg-
ular wave front.
On the basis of the computation of a wave
Claudia Moreau,1 Claude Bhérer,1 Hélène Vézina,2 Michèle Jomphe,2 front index (WFI) (21), we find that the ancestors
Damian Labuda,1,3* Laurent Excoffier1,4,5* of the Saguenay and the Lac-Saint-Jean people
lived more often on or close to the wave front
Since their origin, human populations have colonized the whole planet, but the demographic than expected by chance (WFI, P < 0.001 in both
processes governing range expansions are mostly unknown. We analyzed the genealogy of more regions) (fig. S1). Indeed, the very high WFI of
than one million individuals resulting from a range expansion in Quebec between 1686 and 1960 0.75 observed in Lac-Saint-Jean corresponds to
and reconstructed the spatial dynamics of the expansion. We find that a majority of the present a situation in which half of the Lac-Saint-Jean
Saguenay Lac-Saint-Jean population can be traced back to ancestors having lived directly on or ancestors had lived directly on the wave front and
close to the wave front. Ancestors located on the front contributed significantly more to the current the other half just one generation away from it.
gene pool than those from the range core, likely due to a 20% larger effective fertility of women In contrast, WFI is significantly lower in the
on the wave front. This fitness component is heritable on the wave front and not in the core, Charlevoix region (P = 0.003) (fig. S1). These
Downloaded from www.sciencemag.org on March 24, 2013
implying that this life-history trait evolves during range expansions. results are consistent with different colonization
dynamics of SLSJ and Charlevoix. The wave
front was always widespread in SLSJ where new
M
ost species go through environmental- Quebec parish registers that document the recent localities were continuously settled, whereas it was
ly induced range expansions or range temporal and spatial expansion of the settle- much smaller in Charlevoix where most localities
shifts (1), promoting the evolution of ment of the Charlevoix Saguenay Lac-Saint- remained in the range core until the 20th century
traits associated with dispersal and reproduction Jean (ChSLSJ) region, northeast of Quebec City, (Fig. 1). New immigrants from outside ChSLSJ
(2). Humans likely colonized the world by a Canada: a prime example of a recent, fast, and constituted an important minority of the people
series of range expansions from Africa (3), pos- well-documented range expansion (17) (Fig. 1). getting married, with a greater proportion of im-
sibly with episodes of interbreeding with now The European colonization of Quebec was ini- migrants settling on the wave front than on the
extinct hominins (4, 5), leading to allele frequen- tiated in 1608 with the foundation of Quebec range core, especially before 1900 (up to 20% on
cy and heterozygosity clines from entry points City, and the colony was well established by the the wave front and up to 10% in the range core)
into several continents [e.g., (6, 7)]. Range ex- end of the 17th century (18). The peopling of the (table S2). Generally, more male than female im-
pansions can also lead to drastic changes in allele Charlevoix region started from Baie-Saint-Paul, migration occurred in all regions, and this bias
frequencies, sometimes mimicking the effect of and both a rapid demographic growth and the de- toward males is significantly higher in the core
positive selection in recently colonized habitats velopment of the timber industry promoted further than on the wave front (table S3). Nevertheless,
(8, 9), through a process called gene surfing (9). expansions after 1838 up the Saguenay River and the new territories of SLSJ have been largely col-
Neutral, favorable, or even deleterious mutations the Lac-Saint-Jean region (SLSJ) (19, 20). The onized by people recruited directly on the wave
can surf and increase in frequency (10, 11), im- spatial and temporal dynamics of the peopling of front or next to it, not by people from the range
plying that wave fronts may harbor mutations the whole ChSLSJ region can be reconstructed by core (table S4).
with a wider range of selective coefficients than
core populations. The evolutionary consequences
of range expansions have been studied in a wide
array of species (2, 12), but studies of the dy-
namics of range expansions have been generally
restricted to species with short generation times Saguenay River
(13, 14) or to invasive species (15, 16), because