david comas

7/30/2019 David Comas

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Genes, peoples, and languages

across the Western Mediterranean

David ComasUnitat de Biologia EvolutivaUniversitat Pompeu Fabra

[email protected]


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Sahara Desert


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Objectives

Elucidate the genetic structure of

NW African and SW European populations

Compare the genetic composition

of both Mediterranean shores

Detect possible sub-Saharan

Africa admixture in NW Africa

Compare the genetic composition of

Berber and Arab populations in NW Africa


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Genetic markers

Classical polymorphisms: proteins

Autosomal markers: STRs, Alu insertions

Uniparental markers: Y-chromosome and mtDNA

DNA markers


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Cavalli-Sforza LL, Menozzi P, Piazza A (1994). The history and geography of human genes

Classical genetic markers in Europe

First Principal Component (28.1%)


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Classical genetic markers in North Africa

First Principal Component (36.5%)

Bosch E, Calafell F, Prez-Lezaun A, Comas D, Mateu E, Bertranpetit J (1997)Population history of North Africa: evidence from classical genetic markersHum Biol69: 295-311


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Simoni L, Gueresi P, Pettener D, Barbujani G (1999)Patterns of gene flow inferred from genetic distances in the Mediterranean regionHum Biol71:399-415

Classical genetic markers in the Mediterranean

Sharpest genetic boundaries


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From Arnaiz-Villena and Martnez-Laso (1997)Origen de ibricos, vascos y argelinosInvestigacin y Ciencia

A30-B18-DR3

A1-B8-DR3A29-B44-DR7A1-B57-DQ2A11-B27-DR1

A30-B18-DR3A1-B8-DR3A29-B44-DR7A33-B14-DR1

A30-B18-DR3

A33-B14-DR1A1-B57-DQ2A2-B35-DR11

Classical genetic markers: HLA evidence


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91 41

78

8090

6635

Neighbor-joining tree based on 7 HLA loci

Comas D, Mateu E, Calafell F, Prez-Lezaun A, Bosch E, Martnez-Arias R, Bertranpetit J (1998)HLA class I and class II DNA typing and the origin of Basques. Tissue Antigens 51: 30-40

Classical genetic markers: HLA evidence


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PORTUGUESE

BASQUESCATALANS

ANDALUSIANS

MOZABITES

NC

BERBERS

ARABS

SO BERBERS

SAHARAWI

Autosomal STRs (Short Tandem Repeats)D3S1358 (TCTA)n

vWA* (TCTA)n

FGA (CTTT)n

D8S1179 (TCTA/G)n

D21S11 (TCTG/TA)n

D18S51 (AGAA)n

D5S818* (AGAT)n

D13S317 (GATA)n

D7S820* (GATA)n

TH01 (CATT)n

TPOX (AATG)nCSF1PO (AGAT)n

(GATA)n(GATA)n

(GATA)n

(GATA)n(GATA)

n(AGAT)n(AAAG)n

(ATTT)n(GATA)n

D11S2010

D13S767

D14S306

D18S848

D2S1328

D4S243

F13A1

FES / FPS

D9S926

21STRs

AACTTGCTAAGATAGATAGATAGATAGATAGCGCGCC

AACTTGCTAAGATAGATAGATAGATAGCGCGCC


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-30

-20

-10

0

10

20

30

40

-60 -40 -20 0 20 40 60

75%AFRICANAMERICANS

MOZABITES

SAHARAWI

ARABS

NCBERBERS

SO

BERBERS

ANDALUSIANS

PORTUGUESE

ITALIANS

EUROPEAN

AMERICANS

CATALANS

BASQUES

Bosch E, Calafell F, Prez-Lezaun A, Clarimn J, Comas D, Mateu E, Martnez-Arias R,Morera B, Brakez Z, Akhayat O, Sefiani A, Hariti G, Cambon-Thomsen A, Bertranpetit J (2000)Genetic structure of north-west Africa revealed by STR analysis. Eur J Hum Genet 8: 360-366

Autosomal STRs (Short Tandem Repeats)


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Alu insertion polymorphisms

BASQUESCATALANS

ANDALUSIANS

ALGERIANSN. MOROCCANSW. MOROCCANS

SE. MOROCCANS

SAHARAWI

TUNISIANS

Alu element

Alu element

A25 ACE APO B65 D1 FXIIIB PV92 TPA25 HS243 HS323 HS465

11 Alu insertion polymorphisms

-/- +/- +/+


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0

10

20

30

40

50

60

70

80

90

100

A25

ACE

APO

B65

D1

FXIIIB

PV92

TPA25

HS243

HS323

HS465

Basque

Catalan

Andalusian

Saharawi

E.MoroccanW.Moroccan

N.Moroccan

Algerian

Tunisian

Comas D, Calafell F, Benchemsi N, Helal A, Lefranc G, Stoneking M, Batzer MA, Bertranpetit J,Sajantila A (2000). Alu insertion polymorphisms in NW Africa and the Iberian Peninsula:evidence for a strong genetic boundary through the Gibraltar Straits. Hum Genet 107:312-319



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Basque

AndalusianCatalan

NorthernMoroccan

WesternMoroccan S. Eastern

Moroccan

SaharawiTunisian

Algerian

98.7

60.4

60.4

85.728.9

46.3

Neighbor-joining tree

of populations

11 Alu insertion loci

1,000 bootstrap iterations

NW Africans

Iberians



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S.EasternMoroccan

Saharawi

WesternMoroccan

Catalan

Andalusian

Basque

Northern

MoroccanTunisian

Algerian

First PC (48.0%)

S

econdPC(20.8%)

Principal component analysis of the Alu insertion frequencies



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!Kung

Nguni

Bantu

SEMoroccansSaharawi

Algerians

85.882.9

96.9

1,000 bootstrap iterations

Sub-Saharans

NW Africans

Europeans


Neighbor-joining tree

of populations

11 Alu insertion loci


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First PC (44.9%)

SecondPC(2

4.2

%)

Principal component analysis of the Alu insertion frequencies


Sub-Saharans

NW Africans

Europeans


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?

3 individuals: 2 Basques and 1 Northern Moroccan


Larger Alu insertion in PV92 locus


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Alu element

Alu element

Alu element



Comas D, Plaza S, Calafell F, Sajantila A, Bertranpetit J. (2001)Recent insertion of an Alu element within a polymorphic human-specific Alu insertion.

Mol Biol Evol 18:85-88


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3 individuals: 2 Basques and 1 Northern Moroccan


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mtDNA

autosomes

Y chromosome


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Five generations

MALE

FEMALE

16 Great-greatgrandparents

Son

FatherMother

4 Grand-parents

8 Great-grand-Parents 32 Great

great-greatgrandparents


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Y Adam and mtDNA Eve

2

3

4

5

6

7

8

1

generations

MRCA


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mtDNA phylogenyY-chromosome phylogeny


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Phylogeography: ex. Y-chromosome


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Gender specific behaviours

Patrilocality: females aremore likely to move from their

birthplace upon marriage thanmales

Polygyny: certain men father a

disproportionately large numberof children compared to other men


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Y-chromosome lineages

BASQUESCATALANS

ANDALUSIANS

NC

BERBERS

ARABS

SO BERBERS

SAHARAWI

DYS388 DYS19 DYS390 DYS391 DYS392 DYS393 DYS389I DYS389II

+ 8 STRs44 binary

Bosch E, Calafell F, Comas D,Oefner PJ, Underhill P, Bertranpetit J (2001)

High-resolution analysis of human Y-chromosome variation shows a sharp discontinuity

and limited gene flow between Northwestern Africa and the Iberian PeninsulaAm J Hum Genet 68: 1019-1029


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E3a*



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E3b2



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F*



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R1*



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Iberian Peninsula

NW Africa

North African Paleolithic substrate 75%

Sub-Saharan

genetic flow 8%

North African genetic flow 5.2%

Neolithic contribution 16.4%

Neolithic

contribution

13.6%

European Paleolithic

substrate78.4%

Iberian genetic

flow 2.8%



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Mauritanians

Saharawis

SBerbers

MArabsNBerbers

Mozabites

Algerians

Tunisians

SItalians

CItalians

Tuscans

Sardinians

CatalansBasques

Galicians

ValenciansAndalusians

Central SpainNPortuguese

CPortuguese

SPortuguese

Portuguese

Sicilians

Mitochondrial lineages

Plaza S, Calafell F, Helal A, Bouzerna, Lefranc G, Bertranpetit J, Comas D (2003)

Joining the Pillars of Hercules: mtDNA sequences show multidirectional gene flow in the Western Mediterranean

Ann Hum Genet 67: 312-328

HVS I Control Region

+ 4 SNPs Coding Region 10400

12308

12705

10873


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mtDNA haplogroups defined by

control region sequences

and coding polymorphisms



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First principal co-ordinate (55.4%)

.8.6.4.20-.2-.4

Secondprincipalco-or

dinate(12.7

%)

.8

.6

.4

.2

-.0

-.2

-.4

-.6

Valencians

CSCI SPort

Central Portuguese

North

Portuguese

Portuguese

Galicians

Basques

Catalans

AndTus

South

Italians

SicSard

Mauritanians

Saharawi

SBerbersM Arabs

M Berbers

Mozabites

Algerians

Tunisians

Plot of the two principal co-ordinate scores based on genetic distances


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L1L2

L3

Haplogroup L



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U/K

U6


Haplogroup U/K

180

278

311 290

311

278

261174

188

163

164

129

271

222

239

311

172

297

111

293180

189

359182

192

235

355

145

311

051

Italians

IberiansNorth Africans

U6b


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H

V

HV


Haplogroup H and V

153

189

075

240

259

183

189254216140

291

249

362298

256

304

235

153093

259037264

086172 344

311129

242

124

319

039240

261

169

339

265

129

Italians

Iberians

North Africans


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M1


Haplogroup M

M5


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Sened

Matmata

Chenini-Douiret


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-3,0

-2,0

-1,0

0,0

1,0

2,0

3,0

-2,0 -1,0 0,0 1,0 2,0

W

U6V

L2

L1 L3

UH

M1X

J

Other

N K

I

T

HV

J/T

Mozabites C.Moroccan2

Mauritanians

Tuareg

Saharawi

Moroccan

S.Moroccan

MatmataAlgerian

SenedTunisian

C.Moroccan1

Egyptians Chenini-Douiret

mtDNA haplogroup

Arab

Berber

Fadhlaoui-Zid K, Plaza S, Calafell F, Ben Amor M, Comas D, Bennamar El Gaaied A (2004)

Mitochondrial heterogeneity in Tunisian Berbers. Ann Hum Genet 68: 222-233

Correspondence analysis based on haplogroup frequencies


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Arabs 1.54** 98.46

Berbers 6.24** 93.76

Analysis of the molecular variance (AMOVA)

ns not significat

** p < 0.01

Fadhlaoui-Zid K, Plaza S, Calafell F, Ben Amor M, Comas D, Bennamar El Gaaied A (2004)

Mitochondrial heterogeneity in Tunisian Berbers. Ann Hum Genet 68: 222-233

All populations 4.14** 95.86

Arabs-Berbers -0.21 ns 4.25** 95.95

Groups Among groups Among populations Within populations


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1) Clear genetic difference between NW Africa and SW Europe

The Palaeolithic and Neolithic may have run in parallel along the two shores

Gibraltar Straits may have acted as a geographical barrier

Little genetic impact in Iberia of Arab occupation

Western Mediterranean populations: Conclusions


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2) Sub-Saharan flow detected in some NW African samples

Continuous gene flow through the Sahara desert

South-north gradient of sub-Saharan admixture



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3) No differences between Berber and Arab samples

Arabisation in the Maghreb (7th and 11th C A.D.):

Cultural replacement with little demographic impact



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4) Greater heterogeneity in NW Africa

Genetic drift in isolated populations

Differential genetic admixture

Population sampling bias ?


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Genes, peoples, and languages

across the Western Mediterranean

David ComasUnitat de Biologia EvolutivaUniversitat Pompeu Fabra

[email protected]

david comas

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