Sin ttulo de diapositiva

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Genes, peoples, and languages across the Western
Mediterranean
David Comas Unitat de Biologia Evolutiva Universit
at Pompeu Fabra Barcelona david.comas_at_upf.edu
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(No Transcript)
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Objectives
Elucidate the genetic structure of NW African and
SW European populations
Compare the genetic composition of both
Mediterranean shores
Compare the genetic composition of Berber and
Arab populations in NW Africa
Detect possible sub-Saharan Africa admixture 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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Classical genetic markers in Europe
First Principal Component (28.1)
Cavalli-Sforza LL, Menozzi P, Piazza A (1994).
The history and geography of human genes
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Classical genetic markers in North Africa
First Principal Component (36.5)
Bosch E, Calafell F, Pérez-Lezaun A, Comas D,
Mateu E, Bertranpetit J (1997) Population history
of North Africa evidence from classical genetic
markers Hum Biol 69 295-311
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Classical genetic markers in the Mediterranean
Sharpest genetic boundaries
Simoni L, Gueresi P, Pettener D, Barbujani G
(1999) Patterns of gene flow inferred from
genetic distances in the Mediterranean region Hum
Biol 71399-415
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Classical genetic markers HLA evidence
A30-B18-DR3 A1-B8-DR3 A29-B44-DR7 A1-B57-DQ2 A11-B
27-DR1
A30-B18-DR3 A33-B14-DR1 A1-B57-DQ2 A2-B35-DR11
A30-B18-DR3 A1-B8-DR3 A29-B44-DR7 A33-B14-DR1
From Arnaiz-Villena and Martínez-Laso (1997)
Origen de ibéricos, vascos y argelinos Investigac
ión y Ciencia
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Classical genetic markers HLA evidence
Neighbor-joining tree based on 7 HLA loci
Comas D, Mateu E, Calafell F, Pérez-Lezaun A,
Bosch E, Martínez-Arias R, Bertranpetit J
(1998) HLA class I and class II DNA typing and
the origin of Basques. Tissue Antigens 51 30-40
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Autosomal STRs (Short Tandem Repeats)
AACTTGCTAAGATAGATAGATAGATAGCGCGCC
AACTTGCTAAGATAGATAGATAGATAGATAGCGCGCC
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Autosomal STRs (Short Tandem Repeats)
40
30
MOZABITES
20
BASQUES
ARABS
10
ITALIANS
NC BERBERS
SAHARAWI
ANDALUSIANS
0
-60
-40
-20
0
20
40
60
SO BERBERS
EUROPEAN AMERICANS
PORTUGUESE
-10
CATALANS
AFRICAN AMERICANS
-20
75
-30
Bosch E, Calafell F, Pérez-Lezaun A, Clarimón J,
Comas D, Mateu E, Martínez-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
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Alu insertion polymorphisms
Alu element
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Alu insertion polymorphisms
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
107312-319
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Alu insertion polymorphisms
Neighbor-joining tree of populations
11 Alu insertion loci
NW Africans Iberians
1,000 bootstrap iterations
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Alu insertion polymorphisms
Principal component analysis of the Alu insertion
frequencies
S.Eastern Moroccan
Basque
Saharawi
Catalan
Andalusian
Second PC (20.8)
Western Moroccan
Northern Moroccan
Tunisian
Algerian
First PC (48.0)
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Alu insertion polymorphisms
Neighbor-joining tree of populations
11 Alu insertion loci
Algerians
Tunisians
WMoroccans
NMoroccans
Catalans
Nguni
Andalusians
Basques
85.8
82.9
French
96.9
Saharawi
Swiss
Bretons
SEMoroccans
Bantu
!Kung
Sub-Saharans NW Africans Europeans
1,000 bootstrap iterations
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Alu insertion polymorphisms
Principal component analysis of the Alu insertion
frequencies
Second PC (24.2)
Sub-Saharans NW Africans Europeans
First PC (44.9)
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Alu insertion polymorphisms
Larger Alu insertion in PV92 locus
3 individuals 2 Basques and 1 Northern Moroccan
?
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Alu insertion polymorphisms
Larger Alu insertion in PV92 locus
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 1885-88
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Alu insertion polymorphisms
Larger Alu insertion in PV92 locus
3 individuals 2 Basques and 1 Northern Moroccan
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Uniparental markers Y-chromosome and mtDNA
mtDNA
Y chromosome
autosomes
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Uniparental markers Y-chromosome and mtDNA
Five generations
MALE
FEMALE
Mother
Father
4 Grand- parents
8 Great- grand- Parents
Son
16 Great-great grandparents
32 Great great-great grandparents
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Uniparental markers Y-chromosome and mtDNA
Y Adam and mtDNA Eve
MRCA
1
2
3
4
generations
5
6
7
8
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Uniparental markers Y-chromosome and mtDNA
mtDNA phylogeny
Y-chromosome phylogeny
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Uniparental markers Y-chromosome and mtDNA
Phylogeography ex. Y-chromosome
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Uniparental markers Y-chromosome and mtDNA
Gender specific behaviours
? Patrilocality females are more likely to
move from their birthplace upon marriage than
males
? Polygyny certain men father a
disproportionately large number of children
compared to other men
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Y-chromosome lineages
BASQUES
CATALANS
ANDALUSIANS
NC BERBERS
ARABS
SO BERBERS
SAHARAWI

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 Peninsula Am
J Hum Genet 68 1019-1029
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Y-chromosome lineages
E3a
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Y-chromosome lineages
E3b2
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Y-chromosome lineages
F
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Y-chromosome lineages
R1
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Y-chromosome lineages
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Y-chromosome lineages
North African genetic flow 5.2
European Paleolithic substrate 78.4
Neolithic contribution 16.4
Iberian Peninsula
Iberian genetic flow 2.8
Neolithic contribution 13.6
Sub-Saharan genetic flow 8
North African Paleolithic substrate 75
NW Africa
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Mitochondrial lineages
Tuscans
Galicians
Basques
Catalans
CItalians
NPortuguese
Central Spain
CPortuguese
SItalians
Portuguese
Andalusians
Valencians
Sardinians
SPortuguese
Sicilians
Tunisians
Algerians
NBerbers
MArabs
Mozabites
SBerbers
Saharawis
Mauritanians
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
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Mitochondrial lineages
mtDNA haplogroups defined by control region
sequences and coding polymorphisms
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Plot of the two principal co-ordinate scores
based on genetic distances
.8
Mozabites
.6
.4
Portuguese
North Portuguese
.2
Catalans
Second principal co-ordinate (12.7)
Sard
M Berbers
Galicians
Sic
Saharawi
CS
-.0
CI
SPort
And
SBerbers
Basques
Tus
M Arabs
Valencians
Central Portuguese
-.2
Mauritanians
Tunisians
South Italians
-.4
Algerians
-.6
.8
.6
.4
.2
0
-.2
-.4
First principal co-ordinate (55.4)
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Mitochondrial lineages
Haplogroup L
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Mitochondrial lineages
Haplogroup U/K
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Mitochondrial lineages
Haplogroup H and V
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Mitochondrial lineages
Haplogroup M
M1
M5
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Mitochondrial lineages
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Mitochondrial lineages
3,0
J/T
W
2,0
C.Moroccan1
1,0
Mozabites
C.Moroccan2
T
J
U6
H
U
V
N
K
S.Moroccan
X
M1
0,0
Moroccan
Algerian
Chenini-Douiret
Mauritanians
Egyptians
Matmata
Tunisian
Saharawi
Sened
HV
L1
L3
-1,0
Other
I
L2
Tuareg
-2,0
-3,0
-2,0
1,0
2,0
0,0
-1,0
Correspondence analysis based on haplogroup
frequencies
Fadhlaoui-Zid K, Plaza S, Calafell F, Ben Amor M,
Comas D, Bennamar El Gaaied A (2004) Mitochondria
l heterogeneity in Tunisian Berbers. Ann Hum
Genet 68 222-233
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Mitochondrial lineages
Analysis of the molecular variance (AMOVA)
Arabs 1.54 98.46 Berbers 6.24
93.76
Groups Among groups Among populations Within
populations
All populations 4.14 95.86
Arabs-Berbers -0.21 ns 4.25 95.95
ns not significat p lt 0.01
Fadhlaoui-Zid K, Plaza S, Calafell F, Ben Amor M,
Comas D, Bennamar El Gaaied A (2004) Mitochondria
l heterogeneity in Tunisian Berbers. Ann Hum
Genet 68 222-233
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Western Mediterranean populations Conclusions
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
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Western Mediterranean populations Conclusions
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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Western Mediterranean populations Conclusions
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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Western Mediterranean populations Conclusions
4) Greater heterogeneity in NW Africa
Genetic drift in isolated populations Differentia
l genetic admixture Population sampling bias ?
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Genes, peoples, and languages across the Western
Mediterranean
David Comas Unitat de Biologia Evolutiva Universit
at Pompeu Fabra Barcelona david.comas_at_upf.edu