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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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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

of the populations of

these islands ?

Successive waves of

invasion

versus

Cultural exchange with

little or no movement of

people


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’



‘Keltic’

Aran Islands

Waterford

‘Dinaric’

Harvard University Anthropological Survey of Ireland



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


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%


  • 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


Anatomically Modern Humans

- a brief history


Hominid

Evolution

Anatomically

Modern Humans

[AMH] emerged

some 150 kYBP


Neanderthals and AMH did not interbreed

Ancient & modern mtDNA; MDS analysis

Krings et al., 1997

Caramelli et al., 2003


Neanderthals and AMH did not interbreed

Ancient & modern mtDNA; MDS analysis

Krings et al., 1997

Caramelli et al., 2003


Neanderthals and AMH did not interbreed

Ancient & modern mtDNA; MDS analysis

Krings et al., 1997

Caramelli et al., 2003


‘Out of Africa’

- a global palaeolithic population expansion



Genetic traces of the neolithic expansion

Cavalli-Sforza et al., 1994


The ‘Atlantic fringe’ of Europe

North-western Europe is different


Y-chromosome haplogroup 1.15

Hill et al., 2000


Y chromosome haplogroup diversity (a)

Haplogroup 1.15 – the ‘Atlantic Modal Haplotype’

Wilson et al., 2001


Y chromosome haplogroup diversity (b)

A Y haplogroup spectrum shared with the Basques

- a palaeolithic ‘remnant’

Wilson et al., 2001


Y chromosome haplogroup diversity (c)

Little similarity to the Near East  relatively little

Neolithic influence on the ‘Atlantic’ populations

Wilson et al., 2001


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


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


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



6,000 – 4,000 YBP

Ireland & Britain were

part of a Megalithic

culture spread across

Western Europe

Palaeolithic & Neolithic

admixture of peoples


The Celts were much later !

1st millennium BC


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


Genetic evidence of more recent events

in the population of these islands ?


Y chromosome census

of the British Isles

Samples:

UK + Irl: 1,772

Norway: 201

Denmark }: 190

N. Germany}

Capelli et al., 2003


Reference populations

Capelli et al., 2003


Interpreting the data ?

Capelli et al., 2003


Overall, a degree of similarity

AMH+1 > 33%

Capelli et al., 2003




Recessive disease mutations

Phenylketonuria (PKU) and the population

history of Ulster


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


Using PKU

mutations to

estimate Scottish

admixture in

Ulster


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



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


“…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


Suggested reading: 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…”

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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