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BAHSHE. 07-07-2003. Blood unites us: genetics and the population history of the British Isles. David T. Croke Royal College of Surgeons in Ireland. [email protected] History. Anthropology. Archaeology. Human origins & population history. Genetics. Linguistics. What is the true history

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slide1
BAHSHE

07-07-2003

Blood unites us: genetics and the

population history of the British Isles

David T. Croke

Royal College of Surgeons in Ireland

[email protected]

slide3
History

Anthropology

Archaeology

Human origins & population history

Genetics

Linguistics

slide4
What is the true history

of the populations of

these islands ?

Successive waves of

invasion

versus

Cultural exchange with

little or no movement of

people

slide5
Themes

Genetic variation as a tool to ‘probe’ population history

Anatomically Modern Humans - a brief history

Palaeolithic & Neolithic Europe - the ‘Atlantic fringe’

More recent events in the population of these islands

Population admixture in Ulster

Genetics and ‘race’

slide7
‘Keltic’

Aran Islands

Waterford

‘Dinaric’

Harvard University Anthropological Survey of Ireland

slide9
Genetic ‘markers’ used in population studies

1. ‘Classical’ protein markers

2. Y-chromosome - paternally inherited

3. Mitochondrial DNA - maternally inherited

(mtDNA)

4. Recessive disease genes - biparentally inherited

slide10
The amount & rate of accumulation of variation can

be used to infer genetic relationship / ancestry

Surveys within species reveal enormous genetic variation between individuals

On average, about 0.2% of our DNA differs between individual human beings

Human and Chimpanzees differ by ≤ 2%

slide12
Tools
  • 1. Availability of the human genome sequence and of
    • genetic ‘markers’
  • 2. Laboratory methods
  • - Polymerase Chain Reaction [PCR]
  • - DNA samples from modern populations
  • - ‘Ancient DNA (aDNA)’
  • 3. Population genetics theory
  • 4. Mathematical & statistical tools
slide14
Hominid

Evolution

Anatomically

Modern Humans

[AMH] emerged

some 150 kYBP

slide15
Neanderthals and AMH did not interbreed

Ancient & modern mtDNA; MDS analysis

Krings et al., 1997

Caramelli et al., 2003

slide16
Neanderthals and AMH did not interbreed

Ancient & modern mtDNA; MDS analysis

Krings et al., 1997

Caramelli et al., 2003

slide17
Neanderthals and AMH did not interbreed

Ancient & modern mtDNA; MDS analysis

Krings et al., 1997

Caramelli et al., 2003

slide18
‘Out of Africa’

- a global palaeolithic population expansion

slide22
The ‘Atlantic fringe’ of Europe

North-western Europe is different

slide24
Y chromosome haplogroup diversity (a)

Haplogroup 1.15 – the ‘Atlantic Modal Haplotype’

Wilson et al., 2001

slide25
Y chromosome haplogroup diversity (b)

A Y haplogroup spectrum shared with the Basques

- a palaeolithic ‘remnant’

Wilson et al., 2001

slide26
Y chromosome haplogroup diversity (c)

Little similarity to the Near East  relatively little

Neolithic influence on the ‘Atlantic’ populations

Wilson et al., 2001

slide27
6%

19%

67%

15%

21%

81%

23%

91%

41%

82%

14%

100%

10%

0%

63%

100%

Neolithic contribution in Europe [Y data]

Chikhi et al., 2002

slide28
mt DNA

Y DNA

Different male & female population histories [a]

Y chromosome --> male-mediated gene-flow

mt-DNA --> female-mediated gene-flow

Wilson et al., 2001

slide29
mt DNA

Y DNA

Different male & female population histories [b]

More female-mediated gene-flow (migration) between continental Europe and the Atlantic populations (excluding the Basques)

Wilson et al., 2001

slide31
6,000 – 4,000 YBP

Ireland & Britain were

part of a Megalithic

culture spread across

Western Europe

Palaeolithic & Neolithic

admixture of peoples

slide33
Celticisation of

these islands ?

current model:

diffusion of elements

of celtic culture via

trading links

adoption of the celtic

‘cultural package’ by

local ruling elites

Cunliffe, 2001

slide34
Genetic evidence of more recent events

in the population of these islands ?

slide39
Y chromosome census

of the British Isles

Samples:

UK + Irl: 1,772

Norway: 201

Denmark }: 190

N. Germany}

Capelli et al., 2003

slide40
Reference populations

Capelli et al., 2003

slide41
Interpreting the data ?

Capelli et al., 2003

slide42
Overall, a degree of similarity

AMH+1 > 33%

Capelli et al., 2003

slide45
Recessive disease mutations

Phenylketonuria (PKU) and the population

history of Ulster

slide46
Unidentified

Others

R408W

IVS12nt1

R243X

F299C

L348V

I65T

F39L

Phenylketonuria [PKU]

An inherited defect of amino-acid metabolism

Due to mutations in the Phenylalanine

Hydroxylase (PAH) gene [chromosome 12q]

29 different mutations have been identified in Ireland

O’Neill et al., 1995

O’Donnell et al., 2002

slide47
Using PKU

mutations to

estimate Scottish

admixture in

Ulster

slide48
Ireland

Scotland

Ulster

Analysis based on

frequency data for

13 PKU mutations

For Ulster as the

hybrid population

m = 0.46

Admixture proportion estimated as:

m = (q2(rh-r2))/(q1r1-q2r2-rh(q1-q2))

O’Donnell et al., 2002

slide50
H. sapiens (100%)

Between regional

populations

(10%)

Within regional

populations

(90%)

Between local populations

Within regions

(5%)

Between individuals within

local populations

(85%)

Global human genetic diversity

No biological basis for concepts of ‘race’ or ‘ethnicity’

After Relethford, 2003

slide51
“…we must disavow entirely any mystical view of blood as a racial factor. Rather does a study of blood groups show a heterogeneity in the proudest nations and support the view that the races of the present day are but temporary integrations in the constant process of mutation, selection and mixing that marks the history of every living species…”

‘The distribution of the human blood groups’

Arthur Mourant, Oxford, 1954

slide52
Suggested reading:

Steve Olson

‘Mapping human history: discovering the past through

our genes’

Bloomsbury Publishing Inc., 2002

Spencer Wells

‘The journey of man: a global genetic odyssey’

Penguin, 2002

John H. Relethford

‘Reflections of our past: how human history is revealed

in our genes’

Westview Press, 2003

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