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Home , Denisova Cave, Homo antecessor, Homo erectus, Homo ergaster

An extended origin: climate, populations and palimpsests in the evolution of sapiens

Marta Mirazon Lahr

DySoc/NIMBioS Webinar Series on " origins and cultural evolution: Celebrating the 150th anniversary of the Descent of Man“ Late 1980s

• Asynchronicity of change • Discontinuity in regional morphologies • Shared derived features of all living • of Homo sapiens significantly older than those from Eurasia Africa Cann et al. 1987 mt DNA

Manica et al. 2007.

Krings et al. 1997. Cell

Omo Kibish, Herto, Ethiopia, Ethiopia, 200 Ka 160 Ka

Noonan et al. 2006 Science Neanderthal nuclear DNA Finger from Denisova , Altai, that resulted in the first in 2010

Krause J et al. 2010. The complete mitochondrial DNA genome of an unknown hominin from southern . 464: 894‐897.

mtDNA

Meyer M et al. 2013. A mitochondrial genome sequence Sima de los Huesos, Atapuerca, ~ 400 Ka of a hominin from Sima de los Huesos. Nature Meyer M et al. 2017. Nature Nuclear DNA Meyer M et al. 2012. Science

Other hominin genes in : • 0.0% modern human • 0.5% Neanderthal (*** HLA) Xiahe • 0.5‐8% ANCIENT (?) Denisovan genes in other hominins: • 0.0% Denisovan in • 0.2% Denisovan in modern Han Chinese, Dai of Rightmire, 2008 S , Karitiana of Brasil Proteome • ~4‐6 % Denisovan genes in PNG, , Chen et al. 2019. Nature Philippine Negritos Denisovans

Neanderthal

Asians Europeans Africans

Out of Africa Multiregional model Ma Africa E Asia 0 W Asia SE Asia

0.1

0.2 Modern humans Denisovans Neanderthals 0.3

0.4

0.5 ) 0.6 ) Middle 0.78 – 0.13 Ma 0.7

0.8

0.9

1.0

1.1 Pithecanthropus erectus pekinensis 1.2 prev. ) (prev. 1.3

1.4 Homo georgicus)

1.5 (or Homo erectus ( Homo erectus

1.6 Homo erectus

1.7 Early Pleistocene 2.6 – 0.78 Ma (African

1.8 Homo erectus

1.9

2.0 Timing the origin of our lineage

1

1. Separation of Neanderthals and Denisovans (~450 Ka [381‐473 ka]) 2. Separation of sapiens lineage from the Neanderthal/Denisovan lineage 2 (~700 Ka [550‐765 Ka])

Prufer et al. 2014. The complete genome sequence of a Neanderthal from the . Nature Afro‐European interactions – partial dispersals out of Africa

Y chromosome mtDNA, Hohlenstein‐Stadel

Petr M et al. 2020. The evolutionary of Neanderthal and Posth C et al. 2017. Deeply divergent archaic mitochondrial genome Denisovan Y chromosomes. Science 369: 1653‐1656. provides lower time boundary for African into Neanderthals. Nature Comms 8: 16046. Mode 3 Dispersals Model

Mode 3 as shared ancestral trait

Foley & Lahr 1997. Mode 3 and the evolution of modern humans. Cambridge Archaeological Journal 7:3‐36. Mapping a period of multiple Afro‐European contacts

Apidima, , ~210 Ka

Misliya, , ~190 Ka Denisovans

Neanderthal

Asians

Europeans

Africans 0

0.2 sapiens Neanderthals Denisovans

0.5 Homo erectus & 0.7 Homo erectus East Asain Southeast Asian Homo antecessor?

1 Europe / Australia Africa East Asia W Asia Climate change and the Early‐to‐Middle Pleistocene Transition (EMPT)

• Long‐term cooling of sea‐surface temperatures • Increase in amplitude of glacial cycles • Shift from 41,000 to 100,000 mode • Shift to asymmetric glacial cycles: short warm and long cold phases with abrupt endings (terminations)

EMPT warm

Onset of global glaciation; Walker SAHARA; Circulation expansion of East African cold grasslands Climate change and the Early‐to‐Middle Pleistocene Transition (EMPT)

Average temperature relative to today in oCat 45o N to 80o N latitude

EMPT Shift from 41,000 to 100,000 yr long Cold ‐‐‐‐‐‐‐‐‐‐‐‐ Hot cycles TROPICS • Hydrological response to orbital eccentricity/precessional cycles • EFFECT: amplification or dampening of tropical monsoons

• eccentricity minima: weak monsoons at precessional timescales, increased aridity in , “Yellow Sahara” phase • eccentricity maxima: increase in tropical climate variability at 100,000 and 400,000 yr cycles [independent of continental ice volume] with alternating strongest and weakest monsoons [alternating “Green Sahara” and “Desert Sahara” phases]

Adapted from Grant et al. 2017. A 3 million year index of North African humidity/aritidy and the implication of potential pan‐African Humid periods. Quat Sc Rev Wet Dry

Lahr & Foley 1998. Towards a theory of modern human origins: geography, demography and diversity in recent . Ybk Phys Anth Green Sahara

Megadrought at the end of the EMPT – fragmentation of African populations; separation of sapiens and Neanderthal‐ Denisovan lineages Green Sahara

Expansion and structuring of sapiens populations in Africa (and partial dispersals out of Africa)

Hublin JJ et al. 2017. New fossils from , and the pan‐African origin of Homo sapiens. Nature Schlebusch et al. 2017. Southern African ancient estimate modern human divergence to 350,000 to 260,000 ago. Science Green Sahara

Expansion and structuring of sapiens populations in Africa (and partial dispersals out of Africa)

?

Megadrought at the end of the EMPT – fragmentation of African populations; separation of sapiens and Neanderthal‐ Denisovan lineages Local or pan‐African?

Scerri EML et al 2018. Did our evolve in subdivided populations across Africa, and why does it matter

Henn BM et al 2018. Clarifying distinct models of modern human origins in Africa. Current Opinion in Genetics & Development. Major diversity amongst African hominins 400‐200 Ka

Irhoud 315 Ka Florisbad 260 Ka Kabwe 300 Ka Eliye Springs 350 Ka Ndutu 400 Ka naledi 330‐250 Ka

Omo Kibish, Herto, Ethiopia, Ethiopia, 200 Ka 160 Ka LD6 What defines ‘modern humans’?

Palaeontological definition of modern humans • Comparatively tall and narrow body • Large brain hominin • Tall rounded cranium*, with relatively vertical forehead • Comparatively reduced cranial superstructures • Small face positioned under the vault • Mental eminence on *

Neanderthal Modern Human Modern Human Neanderthal

* Apomorphies of Homo sapiens The globular modern human head

• A quantitative measure of the globular modern human head • Genetic association of values of this “index of endocranial shape” amongst Neanderthal introgressed genomic fragments in the genomes of 4468 Europeans • Key SNPs correlations associated with reduced globularity • Correlated SNPs: affect neural expression of 2 genes linked to neurogenesis and myelination

Gunz P et al. 2018. Neanderthal sheds light on modern human endocranial globularity. Curr Biol Expanding the list: Body size and life‐history

Palaeontological definition of modern humans • Comparatively tall and narrow body • Large brain hominin • Tall rounded cranium*, with relatively vertical forehead • Comparatively reduced cranial superstructures • Small face positioned under the vault • Mental eminence on mandible* • Unique life‐history*

Sustained foetal brain growth rates

THE HUMAN Prenatal Infancy Childhood Adolescence Adulthood Senescence LIFE CYCLE

Conception Birth Weaning First reproduction Menopause Death

Longer infancy, Puberty with sustained brain growth Ancestral Homo size and developmentKNM‐WT 15000 D2700/D2735

Stature: KNM‐WT 15000 159 ± 7 cm, (D2700/D2735) 153.1 cm Density curves for P4 crown completion Body mass: KNM‐WT 15000 49.2 kg, DMANISI 41.2 kg Curves: 438 Sudanese children 7‐10 years old Density curves for P4 crown completion

Dean MC 2016. Measures of maturation in early hominins: events at the first transition from australopiths to early Homo. Phil Trans R Soc B 371: 20150234. Ancestral Homo life‐history

Ancestral Homo: large size, encephalised, fast growth

• Energetically very demanding – diet shift, carnivory

• Ecologically effective – early independence, predator risk minimisation

• Socially and behaviourally challenging – likely increase role of social cohesion, provisioning, innovative solutions (?) Modern human life‐history :

 Relatively higher energy budget and reproductive output than apes (“fast”)  Long juvenile period and lifespan (“slow”) UNIQUE

Retzius Periodicity (RP): number of days between the deposition of successive long‐period growth lines in teeth (striae of Retzius in )

 histological manifestation of a neuroendocrine biorhythm (Havers‐Halberg oscillation)  closely related to body mass and BMR, role in regulating pace of life‐history in

Hogg R et al. 2020. A comprehensive survey of Retzius periodicities in fossil hominins and great apes. J Hum Evol 149: 102896 Unique human life‐history

Homo sapiens: large size, encephalised, slow growth

• Energetically efficient – budgeted development through longer ontogeny

• Ecologically challenging – longer dependence on mother, big risk of predation

• Socially and behaviourally very demanding – provisioning of mothers with dependent children, social cohesion and belonging, major pressure on technological solutions, increased dependence on learning social norms and skills, increased importance of social memory

The evolution of modern human hunter‐gatherer societies? • Role of kin and non‐kin • Family units, foraging units, social units – multilevel societies • Shared social norms, social identities, and social

Migliano AB et al. 2017. Characterization of hunter‐gatherer networks and implications for cumulative culture. Nature Hum Behav Green Sahara

Significant adaptive change shaping the origins of Homo sapiens

Behar et al. 2012 AJHG Major outstanding issues Who was the last common ancestor of humans, Neanderthals and Denisovans (HND)?

Probably between 900‐700 Ka • Period of extreme aridity in Africa: population fragmentation • A time when the human/Neanderthal/Denisovan lineage co‐existed with another hominin in Africa  North vs sub‐Saharan Africa?  Homo antecessor ? ATD6‐69

Mounier A & Mirazon Lahr M 2016. Virtual ancestor reconstruction: revealing the ancestor of modern humans and Neandertals. JHE African fossils from this period: too few, each different

KNM‐OL 45500

Daka

Buia Tighenif 3 Where were the ancestors of Neanderthals/Denisovans before they split?

MODEL 1: Neanderthal and Denisovan lineages separate during the process of out‐of‐Africa dispersal  time of split = time of dispersal out of Africa  Implies that ancestor of NEA‐DEN lived in Africa between 700 and 450 Ka  Too late to fit the fossil record? Earliest ages (Ceprano, Sima) ~430 Ka; Petralona?  Implies the rich, African looking (full of cleavers, absent in Europe) at GBY was an earlier (limited?) dispersal

MODEL 2: Neanderthal and Denisovan lineages separate in Eurasia some time after the out of Africa dispersal ?  time of dispersal out of Africa much before split NEA x DEN  Implies that ancestor of NEA‐DEN lived somewhere in Eurasia between 700 and 450 Ka  What Eurasian fossils match the LCA of NEA & DEN?  Earliest “non‐erectus” fossils in China ~350 Ka – where were the Denisovans before? What was the adaptive niche of African small‐bodied Homo?

LD6

LD6 Which Last Common Ancestor (LCA) are we looking for?

Mounier A & Mirazon Lahr M 2019. Deciphering African late Middle Pleistocene hominin diversity and the origin of our species. Nat Comms. 6

1 2

3

African hominins 400(?) – 250 Ka 1. Eliye Springs, West Turkana, 2. Kalakoel 3, West Turkana, Kenya 3. Ndutu, 4 4. Kabwe, 5. Florisbad, 7 6. Jebel Irhoud, Morocco 5 7. How deep is the population structure of African Homo sapiens?

Schlebusch et al. 2017. Southern African ancient genomes estimate modern human divergence to 350,000 to Henn BM et al 2018. Clarifying distinct models of modern human 260,000 years ago. Science origins in Africa. Current Opinion in Genetics & Development. An extended origin 1. Elements of the ‘out of Africa’ model that are consistent with new data • Modern humans have a recent African origin • The main dispersal of modern humans took place in the last 100,000 years and largely replaced Eurasian hominins

2. New insights • The lineages leading to modern humans on the one hand, and Neanderthals/Denisovans on the other originate during a megadrought in Africa • Modern humans dispersed out of Africa multiple times, to different spatial extents and evolutionary impact • The modern human occupation of Eurasia included some assimilation of local archaic populations • All modern humans share unique brain shape and a unique life‐history with major implications towards behaviour and sociality

3. Points of debate • LCA of sapiens/Neanderthal/Denisovans • Spatial/demographic parameters of African origins • Adaptation in the sapiens lineage With thanks to funding bodies and many people, particularly Robert Foley

McDonald Institute