Cavalli-Sforza Luigi Luca. Genes, Peoples and Languages
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Acknowledgments
This book owes
much
to many people.
It
was conceived when I was
invited in 1981
and
1989
to
give a series
of
lectures
at
the
College
de
Fril1lce.
The
"College" is a wonderful institution created by
Francis I to counteract
the
arrogance
and
backwardness
of
the
Sor-
bonne,
and
to exemplify a
center
of
excellence. Jacques Ruffle's
arrangements motivated
me
to
write my lectures, and gave me
the
wonderful chance
to
twice
spend
a month in Paris in
the
spring,
delivering them.
In
1994, Odile Jacob expressed interest in publish-
ing
the
lectures in a new series
of
books based
on
courses at
the
College, and so I rewrote my lectures from scratch for
the
third
time.
The
Italian edition was a fourth opportunity. My former stu-
dent
Mark Seielstad was
not
deterred
by significant differences
between
the
French
and
the
Italian editions,
but
used them both in
order
to improve
the
English translation, which
he
completed while
in
the
throes
of
preparing his Ph.D. dissertation
at
Harvard.
The
need
to
revise
the
English edition was also a new
and
irresistible
temptation for
me
to
update
and
modify
the
book again. This fifth
IX
version has
been
edited
with
great
skill
and
attention
to
clarity,
rigor,
and
accuracy
by
Ethan
N osowsky. I am also grateful
to
Phyllis
Mayberg for
her
help
in
preparing
the
manuscript
and
to Brian
Blanchfield for ushering
ino
press.
Collaboration with experts from
other
fields is essential
when
taking a multidisCiplinary approach. I am
indebted
to
many friends
and
colleagues who, over
the
last fifty years, have
helped
lay
the
foundation for
the
scientific work described in this book.
As
an
expression
of
gratitude,
I'd
like to summarize
the
major collabora-
tions
of
these
many
decades.
I
began
as a geneticist researching bacteria in
the
forties.
In
the
fifties,
when
I was teaching part-time
in
the
University
of
Parma,
Italy, I gradually shifted focus
to
human
population genetics. My
main research
at
Parma
was
the
study
of
the
role
of
chance
in
evolu-
tion, a subject
that
was neglected at
the
time.
The
opportunity to
give a clear, quantitative answer
to
the
problem
was offered
by
the
demographic records
of
the
last
three
centuries
or
more
in a region
where
the
population density varied enormously, very high
in
the
fertile plains, very low
in
the
mountains. Sizes
of
villages
and
migra-
tion
among
them
could
be
estimated from
the
available parish
books.
When
there
are
few parents to pass genes from
one
genera-
tion
to
the
next, chance will cause
important
fluctuations in
the
fre-
quencies
of
types
of
genes found in different villages.
The
effect
of
chance in evolution is called
"drift;
a somewhat misleading name,
because
the
word
practically has
the
opposite meaning in
other
sci-
ences. This research
made
it possible
to
predict
the
variation
between
villages
due
to drift
on
the
basis
of
their
demography,
and
compare
it
with local genetic variation. This
work
and
a parallel
study
of
consanguinity
data
from bishopric archives would
not
have
been
possible without
the
advice, information,
and
help
of
Antonio
Moroni, a Catholic priest,
then
my
student
and
now
professor
of
ecology
at
Parma,
and
Franco
Conterio,
then
postdoctoral fellow
and
now professor
of
Anthropology
at
Parma.
In
the
sixties I moved to
the
University
of
Pavia, Italy,
and
started
generating methods for reconstructing evolutionary trees
of
human
genetic data, in collaboration with Anthony Edwards,
now
at Gonville
x
and Caius College
of
Cambridge. Afterward I researched African
Pygmies in many
expeditions between 1976 and 1985. This work
profited greatly from
my
collaboration with Marcello Siniscalco. then
professor
at
Leyden.
as
well
as
witll anthropologists Colin Turnbull,
now. unfortunately, deceased. and
Barry Hewlett, now a professor
in Vancouver, Washington.
Our
work was
the
subject
of
a book I
edited, published in 1986. called
African Pygmies.
It
soon
became
clear
that
human
population genetics research,
touching as it does
on
many disciplines, could
prosper
only with
the
help
of
scientists from
othe~
disciplines. I moved
to
Stanford in
1971
and
collaborated with archeologist Albert Ammerman, now at
Colgate University, on
the
problem
of
whether, in
the
expansion
of
Neolithic agriculture from
the
Middle
East
to
Europe.
the
farming
technique
or
the
farmers themselves diffused northwest from
the
place
of
origin.
The
study
of
genetic geography was begun in 1977
with
the
collaboration
of
Paolo Menozzi and Albelto Piazza, now
professors
of
ecology
at
Parma
and.
of
human
genetics at Turin
respectively. with the purpose
of
offering a solution to that prob-
lem,
and
we
provided a key
to
the
answer. Eventually this approach
was extended
to
the
rest
of
the
world
and
led
to
the
publication
of
our
History
and
Geography
of
Human Genes in 1994 with Prince-
ton University Press.
It
is
the
source for
the
majority iJf claims made
in
the
first
five
chapters
of
this book. and is referred to by
the
acronym
HGHG.
In
the
seventies and early eighties I dedicated
much
time to
the
study
of
cultural evolution, mostly as a response to
the
personal
and profound interest I developed after observing African Pygmies.
Researching cultural transmission
and
evolution, I gainfully collab-
orated with Marcus Feldman, professor
of
biology
at
Stanford.
Applications to linguistic evolution were made possible thanks to
exchanges with linguists from
the
Bay Area: Bill Wang, from Berke-
ley, Joseph
Greenberg
and
Merritt Ruhlen
at
Stanford.
At
the
end
of
the
seventies
and
beginning
of
the
eighties, with
the
seminal work ofY.
W.
Kan; David Botstein, Ronald Davis, Mark
Skolnick,
and
Ray White,
the
promise
of
chemical analysis
of
DNA-:-the material
of
heredity-started
to
become
reality. Until
XI
that
time,
genes-the
units
of
inheritance-were
interpreted only
through
their
products, mostly proteins.
From
then
on
it became
possible,
and
eventually
much
easier, to study variation
on
DNA
directly. .
Mitochondrial DNA, a small organ
that
is present in every cell
and transmitted to
the
progeny by
the
mother,
was
one
of
the
first
objects
of
study.
We
began this work with
Doug
Wallace and his stu-
dents.
In
the
hands
of
the
late Allan WIlson
of
Berkeley,
it
gave
the
first important· evidence
that
modem
humans appeared in Africa
and from there spread to
the
rest .of
the
world. Now
the
purposes
of
our
research are also served
by
studying Y chromosomes, found only
in males and transmitted from father
to
son. I
was
blessed by a
stroke
of
good luck
when
Peter
Underhill
of
my laboratory
and
Peter
Oefner
of
Ron Davis's laboratory together developed a superior
technique
of
detecting
DNA
variation.
111e
new genealogy
of
Y
chromosome variants they developed will enormously aid
our
understanding
of
the history
of
the
evolution
of
modem
humans.
This research is now progressing
rapiclly.
The
results already
at
hand
promise
to
generate a clear picture
of
the
expansions
and
migrations
out
of
Africa tllat made
modem
humans look
the
way
ti~ey
do today.
It
would seem that these events
were
mucl1
more recent than has
b~en
thought.
It
is impossible to
generate much diversity in such a short period
of
time, which con-
vinces us once
and
for all
that
the
superlicial racial differences we
perceive between people from different continents are
just
that.
XII
G e
De.
s,
P e 0 p
Ie
san
d l a n g u
age
s
CHAPTER
I
Genes
and
History
The
Pride
of
an
Emperor
Dante
Alighieri's reputation
as
the
grand master
of
Italian literature
has eclipsed all
the
Italian poets
and
writers who followed him.
Nevertheless,
Dante
was not
the
only great Italian poet.
There
were others, such
as
Petrarch, Ariosto,
and
Leopardi.
The
latter
is
perhaps
the
least well-known outside Italy, although
he
was
not
only a talented
poet
but
also a remarkable philosopher.
I recently reread
his play Copernicus, which I still find relevant
and insightful. The characters include the
Sun, the First and Last
Hours
of
the
Day;
and Copernicus.
In
the opening scene, the Sun con-
fides
to
the First Hour that
he
is
tired
of
revolving around the Earth
each
day,
and demands that the Earth shoulder some
of
the burden.
The
First Hour, alarmed by this prospect,
pOints
out that the Sun's
retirement would create havoc. But the Sun
is
adamant and insists on
informing Earth's philosophers
of
the impending change since
he
believes they can convince humans
of
anytlling--good
or
bad.
By
the second scene, the Sun has delivered on his threat. Copernicus,
sUlprised by
the
Sun's failure
to
rise, sets about investigating the cause.
His search quickly ends when
he
and the Last
Hour
are summoned
to hear the
Sun's proposal:
the
Earth must renounce her position at
the center
of
the Universe' and instead revolve around the
SUllo
Coper-
nicus notes that even philosophers would have difficulty convincing
'the Earth
of
that, Moreover, the Earth and
her
inhahitants have
grown accustomed to their position at the center
of
the Universe and
have developed
the
"pride
of
an emperor." A change
of
such magni-
n,;de
would have not only physical but also social and philosophical
consequences.
The
most basic assumptions about human life would
be overtumed. But the
Sun
is
insistent that life will go on, that
all
the
barons, dukes, and emperors will continue to believe in their impor-
tance, and that their power won't
be
weakened in the least, Coperni-
cus offers further objections: a galactic revolution could
begin-the
other planets may assert that they want the same rights to centrality
as
the Earth had, Even
the
stars would protest,
In
the end, the
SUll
might
lose
all
impOltance and
be
forced to find another orbit. But the Sun
desires only rest and counters Copen1icus's final
fear-that
he will be
bumed
as
a
heretic-by
telling him
he
can avoid such a fate by dedi-
cating his book to
the
Pope.
In
Wliting about Copernicus, Leopardi
had
the
benefit ofliving
several
centuries after him,
He
knew what
had
happened
to
Coper-
nicus, Giordano Bruno, and Galileo. But
we
do
not
have Leopardi's
advantage
when
considering
the
Scientific issues
of
our
day.
Any
current theOlies may
be
modified
or
even destroyed at any moment.
In
fact, science progresses because every hypothesis can
be
con-
firmed
or
rejected by others.
The
great
number
of
conditionals we
use in
our
scientific prose underscore this truth. While correcting
the
translation
of
one
of
my
books, I was terrified to see that all my
conditionals
had
been
changed
to
indicatives-my
safeguards had
been
eliminated.
When
we write papers for scientific journals, we
know
that
many statements cannot
be
supported in their entirety.
This seems strange to
the
public: isn't science infallible?
In
the
end,
only religion claims
to
deliver certainty.
In
other
words, faith alone
is
immune
from doubt, although few believers
seem
troubled by
the
fact
that
each religion offers different answers. Mathematics
may
be
the
only exception in
the
sciences
that
leaves no room for
skepticism. But,
if
mathematical results are
exact
as
no empirical law
could ever
be,
philosophers have discovered they are not absolutely
novel-instead., they are tautological.
Copernicus also
reminded
me
of
our
attitudes about race and
racism. Each population believes that it is
the
best
in
the
world.
With few exceptions, people love
the
microcosm into which they
are
born
and don't want
to
leave it.
For
Whites,
the
greatest civiliza-
tion
is European;
the
best
race is
White
(French
in
France
and
En-
glish in England).
But
what
do
the
Chinese think? And
the
Japanese? Wouldn't most
of
today's
recent
immigrants return to
their country
if
they
could find a
decent
way
of
life
there?
It
is also true,
as
Leopardi observed, that
the
more things change,
the
more they stay
the
same. Noble
or
economically powerful fami-
lies come and
go-there
is an increasingly rapid turnover
of
power-
but
power structures change very little.
The
Roman Empire lasted
longer than many others in Europe,
but
it spanned only five cen-
turies.
It
was similar in size to
the
Inca Empire, which lasted a little
more than a century. Before
the
Roman Empire, several maritime
powers-the
Greeks, Phoenicians, and Carthag;n;ans---colonized the
Mediterranean coast. At
the
same time,
the
European interior saw
Celtic princes establish control over most
of
Europe. During
the
sec-
ond
half
of
the first millennium
B.C.,
the
Celtic and maritime fief-
doms were each united
by
commercial, linguistic, and cultural ties,
but
were
politically fragmented.
Ultimately,
they
would all fall
to
the
Romans. 'TIle Romans built
the
first politically
united
culture
in
Europe,
but
it
eventually fell
to
"barbarian" invaders from
the
East.
The
barbarians flourished,
and
only
the
eastern
part
of
the
Roman
Empire-the
Byzantine
Empire-was
to survive into
the
Middle Ages.
In-
the
west, Charle-
magne founded
the
Holy Roman
Empire
in
A.D.
800,
the
culmina-
tion
ofFranldsh
political development. France, Germany,
and
parts
of
Italy
and
Spain were briefly reunited. After
A.D.
1000, Frankish
power
passed
to
Germany and, in part,
to
the Pope, although
the
Papacy
and
the
Empire
were often in conflict.
The
Holy Roman
Empire
ceased to have any political importance by
the
fourteenth
century, although Austrian emperors continued to
take
the
title
of
Holy Roman
Emperor
until 1806. Several European states
were
formed
or
consolidated
between
1000 !lnd 1500. Although wars
among
them
were
frequent,
none
was
able
to
conquer
much
of
Europe
before Napoleon. With
the
development
of
seaworthy
ships,
the
armies
and
navies
qf
Europeans attempted
to
extend
their
hegemony
to
the
rest
of
the
world, competing for national
riches
on
other
continents.
The
Portuguese, Spanish, English,
Dutch,
French,
and
Russians established overseas empires which
would
endure
into
the
twentieth century,
but
in all
of
European
his-
tory,
not
a single
empire
has lasted for more
than
five
~nturies.
Napoleon rapidly
conquered
continental Europe,
but
his rule
lasted for fewer
than
ten
years.
The
Chinese
Empire
began in
the
third century
B.C.
and
endured
many vicissitudes
under
myriad dynasties, none
of
which
lasted for more
than
four centuries. After several difficult periOds,
China fell to
the
Mongols in
the
thirteenth century.
One
hundred
years later,
the
Ming restored Chinese dominance for
three
cen-
turies.
Then
another
foreign dynasty,
the
Qing, ruled for several
centuries into
the
twentieth.
The
same
pattern
is found
on
every
continent
or
subcontinent.
National pride is always more fervent in successful times.
When
a
people feels strong, it
is
easier to
say,
'We
are
the
best.~
However,
power can have ratller unusual origins.
The
wise decisions and
shrewd political acts
of
a few leaders
or
small groups often produce
endUring states.
Even
cruel regimes can sometimes succeed in intro-
ducing prosperous periods'.
The
rise to political power frequently
requires violence, which is not always physical. Favorable external
circumstances can also help maintain stability,
if
only temporarily.
Politicians who wield their power responsibly are difficult to replace
with equally capable successors. During happy and'prosperous years,
people can convince themselves that their success
is
due
to their
excellent qualities,
the
intrinsic characteristics
of
their
"race~
that
make
them
great.
The
illusion
of
immortality ignores all
the
lessons