Anthropol.

Sci.

102(2),

129-147,

Population

1994

Genetic
II.

NARUYA
AND

1

2

RUOFU

of

Mishima,Japan

KEIICHI

Evolutionary

Research

Tokyo,

Sinica,OMOTO2,Center

Abstract•ôGS•ôof Medicalin

Hainan

and

those

two

for

Genetics,

betweenpopulations,structedby

using

Li

populations

relatively

China.

other

Asian
and

showedfrom

populations

Divergenceaffinityonsix

between

University

minorities

six

populations

and

one

for

these

to estimate

the

of

China,

Thailanders,

northern

China

Li-Miaosix

populations
distances

networks

Miao

were

con

The

two

populations

HainanwereIslandandandshowedJavanese,(Japanese,
group

Li

population)

respectively.

two

populations

(two

Han

genetic

andmethod,the

19,000-26,000

network,

data
used

while

aroundtime

roughlyethnicout

dendrograms

relationship,

distant

Words•ôGS•ô:

Science,1993

frequency

neighbor-joining

the

These

genetic

Academica

population,

andSouthern

Key

Genetics,

carriedaffinitya close

from

be

of

Hui

geneticoftoof Medical

wereother.

Korean).

Kyoto, andUniversity

wasAlleleeach

andStudies,Yat-sen13,

populations

Zhuangare

Genetics,

of

May

one

with

they

of

SchoolInstitute

study

affinity

estimated•ôGH•ô

genetic

UPGMA

distanta closeSun

Genetics,

populations,SouthernsomeJapanese

Institute

China

Miao

Island,
for

DU3,

China

of HumanBeijing,

A population

populations,

CHUANSHU

National

Graduate

Received•ôGH•ô

China

Japan

Guangzhou,

Department

Island,Analyses

Genetics,of Anthropology,

Sciences,

HainanDU4Department
Tokyo,

inAffinity

International

Department

4

Genetic

SAITOU1,Laboratory

of
3

Study

but

Mongolian,Japanesewasyears.

in China,

population

HainanIsland,ofgenetic

polymorphism,

genetics

I NTRODUCTION
Severalethnicminorities,

Li,

populationsgroupsMiao,

andin Hainan

Chinesefield

surveysampleswereobtained

one

and

Han

Hui

were
frequency

examineddata

arelivinginHainanIsland

In

order

to

understandHui.

Island
was

and

other

carried

out

six

human

from

populations;

see

for

those

six

for

those

loci.

the

includingrelationships

human

populations

in

Asia,

in

and

1987,

and

a

total

(two

Li

and

Miao

A

total

of

al.

(1993)

Omoto

populations

China,

1985
populations
et
and

al.,
Omoto

1993).
etthree

ethnic

among

these

a joint

Japanese-

of

792

blood

populations,23

genetic

presented

lociallele130

SAITOUet al.

The purpose of this paper is to present the result of genetic affinity analyses forthese Hainan Island populations and for surrounding Asian populations. A possible
history of these Hainan Island populations will be discussed based on the resultson genetic affinity.
MATERIAL AND METHODS
Allele frequency data
Omoto et al. (1993) studied six human populations of Hainan Island. These
populations were named Li-1, Li-2, Miao-1, Miao-2, Hui, and Han. Blood samples
for Li-1, Miao-1, and Hui were collected in 1985, and six serum protein loci (Hp,
Tf, Gc, C6, C7, and Bf), seven red blood cell enzyme loci (ACP, ESD, 6PGD,
PGM1, GPT, ADA, and AK), and six blood group loci (ABO, MN, Rh, Duffy, Kell,and Lutheran) were examined, except Rh for Hui. Blood samples for Li-2, Miao2, and Han were collected in 1987, and five serum protein loci (Hp, Tf, Gc, C6,
and Pi), four red blood cell enzyme loci (ACP, ESD, 6PGD, and PGM1), and eight
blood group loci (ABO, MNSs, Rh, Duffy, Kell, Lutheran, P, and Diego) were
examined. Gc and PGM1 loci were subtyped, and "subtype" will be added whensubtyped data are used in the following.
Different sets of genetic loci were examined in the two studies held in 1985 and1987, and data for the following 13 loci are available for all the six Hainan Island
populations: Hp, Tf, Gc-subtype, C6, ACP, ESD, 6PGD, PGM1-subtype, ABO,
MN, Duffy, Kell, and Lutheran. Allele frequency data for these shared loci wereused for genetic affinity analysis of the six populations. Because only Huipopulation lacked the allele frequency data for the Rh blood group locus, data for
14 loci (Rh and the above 13 loci) were also used for estimating the genetic affinityof the remaining five populations (Li-1, Li-2, Miao-1, Miao-2, and Han). Japaneseand English populations were also included in the analysis. Allele frequency data
for Japanese were taken from Omoto (1978) except for Gc-subtype, C6, PGM1subtype, Kell, and Lutheran. Allele frequency data of the Japanese population for
Gc-subtype, C6, and PGM1-subtype were taken from Yuasa et al. (1984), Tokunaga
et al. (1986), and Yuasa et al. (1986), respectively, while those for Kell and Lutheran
were taken from Nakajima (1973). Data for the English population were taken from
Roychoudhury and Nei (1988).
We also compared the six Hainan Island populations with 12 other humanpopulations mostly living in Asia: Mongolian, Zhuang, Japanese, Aim, Korean,Southern Chinese, Malays, Javanese, Thailanders, Filipinos, Negritos (Aetas in thePhilippines), and English. Because C6, Gc, and Lutheran were not examined insome of those populations, allele frequency data for the following 10 loci werecompared: Hp, Tf, ACP, ESD, 6PGD, PGM1, ABO, MN, Duffy, and Kell. In thiscase, conventional electrophoresis data for PGM1 were used, and subtypes were

Genetic

combined

for

Data

for

were

taken

Data

for

taken

from

and

Englishwere(1978)

except

from

Omoto

et

(1978)al.

Southernas(Fujien

and

and

Yuan

et

taken

from

Roychoudhury

data

were
Miao-1,

Hui,

for
al.

Japanese,commonly

examined

loci:

Hp,

Tf,

GPT,

ADA,

AK,

ABO,
taken

for

C7

while
for

data

for

Japanese

were

and

Bf

were

from

Nakamura

those

for

GPT,

EnglishGenetic

were

distances

Two

kinds

standard

of

ADA,

AK

Roychoudhury

andgenetic

affinity

distancesdistance(Dstd).

locus.

for

the

data
Data

four

and

and

Zhuang
for

Nei

Ainu

Negritos

group

were

taken

JX,

2b)

where

and

allele(1988).
compared

C6,

C7,

for

Bf,

the

ACP,

Kell,

and

following

ESD,

6PGD,

Lutheran.

asabove,

withtheadditionalal.

(1984)

andHorai(1976),

respectively,

from

Omoto

(1978).

All

Nei(1988).

One

is Nei's

taken
and

relationship

were

used

Dstd

between5

Allele
loci.

are

Data

the

data

constructionin thepresent

populations

study.
X

and

Y is

(1972)

definedby(1)

definedby

JXY=‡”nk=1‡”mki=1xikyik/n,(2a)

JY=‡”nk=1‡”mki=1yik2/n,(2c)

xik andrespectively,
locus

JY

from

Remaining

Dstd=-log(JXY/•ãJXJY).

JXY,

loci.

Javanese
were

Hp.

were

Duffy,

for
for

blood

Malays,

and

MN,

were

from

genetic

genetic

and

taken

frequency

Kell

exceptGc-subtype,etAlleleMongolianEnglishavailable.

the

those

(1984)

andPGM1-subtype,
frequency

for

were

Province),(1984)

Li-1,

Those

131

data

above.

thoseal.

Lastly,Island-II

subtypedSahaet(1992).

HainanexceptChinese

Tay

in

only

Omoto

frequency

18

which

from

Korean,GoeddeinJapanese

taken

were

populations

Study

k. JX

heterozygosities

yik arefrequencies

n is the number

and JY are homozygosities
or geneof alleleof locidiversities

i of locus

compared,and mkfor populations
for these

populations

k for populations
is the number
X and
are

X and
of alleles

Y, res-pectively,
defined

by

Y,
at
and

132

SAITOU

Dstd

HX=1-Jx,(3a)

HY=1-JY.

(3b)

has

many

et al.

been

shown

genetic

loci

other

genetic

The
which

is

to

be

are

definedproportionalrandomly

withsampleddistance

divergencefrommeasure

used

is

time

of

populations
1987).

thegenome(Nei,

DA

proposed

by

Nei

when

et

al.

(1983),al.,1983).

byDA=‡”nk=1(1-‡”mki=1•ãsikyik)/n. (4)DA

distancewasefficiently

than

It

be

should

shown

to

other
mentioned

Cavalli-Sforza

recover

genetic
that

and

the

true

branchingbycomputerclosely

relateddistances
DA

Edwardsis(1967),

whichispatternof

populations

simulation
tothedefined

(Nei
chord

more

et

distance(DC)

DC=2•ã2DA/ƒÎ.

Genetic(5)

affinity

dendrograms

Sneath,1963),

Genetic

affinity

networks

methodofandsmallestthepopulations

dominant

which

Saitou

the

is

are
factorofminimum

distance

may

not

for

the

(dendrogram),inisclusteredfirst.

to
the

some

an

It
NJ

tree

in

morphologicaltheneighbor-joining

UPGMA,

for

the
is

becomealso

isunrooted

pair
used

noted

pair

with

all

the

distance

a

all

is

the

however,thesmallest

the

the

of

lengths

distance
tree

are

case

branch

UPGMA

the

data

in

estimate
when

that

with
until

populations(neighbors)

negativebe(NJ)

populations

method,toandstudies.

NJ

populationis(Sokalcontinues

betweentheclusteringofprocess

becausemethodshoulda pairthissimilarity

and

the

may

using

and

This

squarebranches

analysis"
by

As

used,

choose

least

UPGMA

of

UPGMA.

evolution

additivity.
while

case

the

Since

from

the

Therefore,clustering

considered

method,Inclustered.

NJ

NJ(1987).

using"clusterclusteredbebyconstructed

first

the

is farcalledwere

aresimultaneouslyusedconstructeddistanceforprinciple

were

often

Nei

genetic

method.

ofbymatrixis

rooted(network).

RESULTS(1)

comparison

of

Li-1,

Miao-1,using

frequency

data

Genetic

alleledistances

between

the

Hui,
for
above

Li-2,
13

Miao-2,polymorphic
eight

populations

Han,

Japanese,andEnglish

loci
using

allelefrequency

dataGenetic

Table

1. Genetic

distances

among

Li-1,

Study

in Hainan

Miao-1,Island-II

Hui, Li-2,

Miao-2,133

and Han populations

Figures above and below the diagonal are DA and Dstd,respectively, and those on the diagonal are genediversity. Allele frequency data for 13 polymorphic loci (Hp, Tf, Gc-subtype, C6, ACP, ESD, 6PGD,
PGM1-subtype, ABO, MN, Duffy, Kell, and Lutheran) were used.

Fig.

1. A UPGMA
distances

dendrogramof Tablefor Li-1,

1 are used.

Miao-1,

Hui, Li-2, Miao-2,

Han, Japanese,and English.

Dstd

134

SAITOU et al.

Fig. 2. NJ networks for Li-1, Miao-1, Hui, Li-2, Miao-2, and Han populations. Each line of the
network is proportional to branch lengths (distances). Negative lengths are shown in brokenlines. (A) Dstddistances of Table 1 were used. (B) DA distances of Table 1 are used.

for 13 polymorphic loci are given below (Dstd)and above (DA)the diagonal in Table
1. Figures on the diagonal are gene diversities (average heterozygosities) for each
population. DAvalues are often smaller than Dstdvalues, and both genetic distances
are much smaller than gene diversities. Clearly, most of the genetic variation exists
within populations.
UPGMA dendrograms constructed by using Dstdand DA distances are shown in
Fig. 1. The clustering pattern of the UPGMA tree (Fig. 1B) based on DA distances
is somewhat different from that (Fig. 1A) based on Dstd, in terms of the clusteringof Han, Miao-2, and Hui. Japanese are slightly distant from those populations, andEnglish are far apart from the remaining populations.
NJ networks constructed by using Dstdand DA distances are shown in Fig. 2. Two
Li populations (Li-1 and Li-2) have the smallest genetic distance and they are always
clustered in all four trees in Figs. 1 and 2. The genetic distance between two Miao
populations (Miao-1 and Miao-2) is much larger than that between the two Li

Genetic Study in HainanIsland-II

135

populations, and they do not form a cluster in any tree. Miao-1 is always locatedat the position of the outgroup to all the remaining five Hainan populations in all
four trees of Figs. 1 and 2.
(2) Comparison of Li-1, Miao-1, Li-2, Miao-2, Han, Japanese, and English using
allele frequency data for 14 polymorphic loci
Genetic distances for the above seven populations using allele frequency data for
14 polymorphic loci are given in Table 2. Allele frequency data for the Rh bloodgroup locus were added by excluding the Hui population from the previous
comparison. Compared to genetic distances of Table 1 in which 13 polymorphic lociwere used, those of Table 2 are slightly larger for many pairs of populations. Thisis probably because there are eight alleles in the Rh locus and the contribution ofFig. 3. UPGMA dendrograms for Li-1, Miao-1, Li-2, Miao-2, Han, Japanese, and English. (A) Dstd
distances of Table 2 were used. (B) DA distances of Table 2 are used.

136

SAITOUet al.

the locus to genetic distances is larger than the average of the 13 polymorphic lociused in the previous section.
UPGMA dendrograms were produced based on Dstd and DA distances (Fig. 3).
Japanese is now clearly distant from the five Hainan Island populations, and English
is far apart from the remaining populations. The two Li populations were clustered
Table 2. GeneticdistancesamongLi-1,Miao-1,Li-2,Miao-2,Han,Japanese,and Englishpopulations

Figures above and below the diagonal are DA and Dstd, respectively, and those on the diagonal are genediversity. Allele frequency data for 14 polymorphic loci (Hp, Tf, Gc-subtype, C6, ACP, ESD, 6PGD,
PGM1-subtype, ABO, MN, Duffy, Kell, Lutheran, and Rh) were used.

Fig. 4. NJ networks for Li-1, Miao-1, Li-2, Miao-2, and Han populations. Each line of the network
is proportional to branch lengths (distances). Negative lengths are shown in broken lines. (A)Dstd distances of Table 2 are used. (B) DA distances of Table 2 are used.

GeneticStudyin HainanIsland-II

137

as in Fig. 1, and the location of Miao-1 is the same for Figs. 1A, 1B, 3A, and 3B.
If we ignore Hui in Fig. 1A, the branching pattern becomes identical with that ofFig. 3A. It should be noted that Dstddistances were used both for Figs. 1A and 3A.
As for the trees in which DAdistances were used, however, there is an inconsistency
on the clustering of Han, Miao-2, and the Li cluster (see Figs. 1B and 3B). This
inconsistency may be explained by small lengths of some internal branches.
NJ networks based on genetic distances of Table 2 are shown in Fig. 4. Now Han
becomes the outgroup to the remaining four Hainan populations in both Figs. 4A
and 4B. The two Li populations clustered in Figs. 2A, 2B, and 4A, whereas they
did not cluster in Fig. 4B, where DAdistances were used. Because the branchingpattern among the five Hainan Island populations differs from tree to tree, therelationship among Han, Miao-1, Miao-2, and the Li cluster is not clear.
It seems that Dstd distances are more stable than DA distances when allele
frequency data for different set of loci are used. Thus only Dstddistances are usedin the following analyses.
(3) Comparison of six populations in Hainan Island with 12 other humanpopulations
using allele frequency data for 10 polymorphic loci
Genetic distances (Dstd)among 18 human populations including the six Hainan
Island populations are given in Table 3, and a UPGMA dendrogram was constructedbased on the genetic distances of Table 3 (see Fig. 5). All the Asian populations
except Negritos (Aetas) of the Philippines are closely related to each other. All thesix populations of the Hainan Island (those with asterisks in Fig. 5) belong to cluster
A, in which Thailanders, Javanese, and Zhuang of southern China are also included.
Two Li populations again make a cluster, and they were closest to Zhuang. On theother hand, populations of East Asia (Japanese, Mongolian, Korean, and Ainu) form
a different cluster, and they show more affinity with Filipinos, Malays, and SouthernChinese than to cluster A.
An NJ network was constructed based on the genetic distances of Table 3. When
all the 18 populations were compared, English and Malays were clustered, and alarge negative branch length was observed for the branch going to Malays (tree notshown). The genetic distance (0.026) between Malays and English is unusuallysmaller than those between the remaining populations and English (the average=
0.063), while distances between Malays and Southern Chinese, Javanese, Thailanders,
Mongolian, and Japanese are smaller than 0.01. This situation is quite different fromthe additivity of branch lengths, which is the ideal situation for the NJ method(Saitou and Nei, 1987), and apparently this created a large negative branch for
Malays. Therefore, English were excluded from the comparison, and the NJ network
for the remaining 17 populations was constructed (see Fig. 6).
Now Malays are clustered with Southern Chinese as in the UPGMA dendrogram

138

SAITOU et al.

Genetic Study in HainanIsland-II

139

of Fig. 5. It is noteworthy that all the six populations of Hainan Island (those withasterisks in Fig. 6) are included in the cluster above the branch A, in which
Thailanders, Javanese, and Zhuang are also included. This cluster corresponds tocluster A of Fig. 5. There are three neighboring pairs of populations in this cluster;[Li-1*, Li-2*], [Miao-2*, Hui*], and [Han*, Thailanders]. The same three pairs of
populations are clustered in the UPGMA dendrogram (see Fig. 5). There are twogroups inside this cluster separated by branch B; one including four ethnic minorities
in southern China (Miao, Li, Hui, and Zhuang) and the other including Thailanders,Javanese, and Han in Hainan Island. The latter group has some affinity with a groupconsisting of Malays, Southern Chinese, and Filipinos, though these two groups are
separated by the relatively long branch A (see Fig. 6).

Fig. 5. A UPGMA
Populations
Hainandendrogramwith asterisks

Islandpopulations.

of 18 humanare those

populations
livingbased

in Hainanon genetic

Island.

Clusterdistance

data of Table

A includes

all those

3.
six

140

SAITOU et al.

Fig. 6. An NJ network of 17 human populations based on genetic distance data of Table 3. Each lineof the network is proportional to branch lengths (distances). Negative lengths are shown in
broken lines. Populations with asterisks are those living in Hainan Island. The cluster above
the branch A includes all those six Hainan Island populations.

The four populations of East Asia (Japanese, Mongolian, Korean, and Ainu) do
not make a single cluster, but they form a group located between the three
populations (Malays, Southern Chinese, and Filipinos)
distant from all the remaining populations.

and Negritos,

which is(4) Comparison of Li-1, Miao-1, Hui, Japanese, and English using allele frequency
data for 18 polymorphic loci and 18 monomorphic loci
Genetic distances (Dstd) among Li-1, Miao-1, Hui, Japanese, and English are
given in Table 4, with their standard errors in parentheses. When genetic distanceswere computed, we used the method of Omoto (1982), who considered a hypotheti
calsituationof the existence of some monomorphic loci to obtain a realistic
divergence time between populations. In the present case, existence of 18
monomorphic loci as well as 18 polymorphic loci was assumed so as to bring the
distance between English and Japanese and gene diversities for these populations
close to the estimates obtained from the comparison of many loci. Nei andGenetic

Roychoudhury(1982)English

and

group

loci,

Japanese)estimatedJapaneseto berespectively,
and

Study

Englishand

Dstd

betweenestimated

In

Table

4,

gene

diversities

areestimated

to

be

both

0.152

or

less

similar

NeedlesstoinTablesFigure

based

1 and

2

the

represent
were

hence

slightlyofgenetic

bypoints
Hui

are

and

assuming

quite

Hainanother

betweenJapaneseandrienceda

certainadmixture.

genetic

distancesthedistances

Figures below the diagonal

of

4.

the
may

18

were

allelefrequency

betweenJapanese

and

Open

boxes

point.

Standard

more(1982).
estimates

loci.

and

an

NJ

in

the

network

UPGMA

errors

In

and

are

Roychoudhury

betweenobtained.

forEnglishdistance

corresponding

monomorphic
7A)

from
data

(Dstd)

genetic

blood

mostly

and

than

(Fig.

for

JapaneseNei

covariancesbea cluster

Hui

group

Therefore

Li-1,

in thepopulations,
between

Li-Miao

among

of

0.20

for

the

smaller

and

(data
on

and

are

0.11

of

any

(Fig.
dendrogram

(SEs)

of

distances
case,

it

7B),

branching
to

be

zero,

that

SEs

is clearlarge.

two

with

4

heterozygosities)

anddistance

diversities

Table

make

smaller

Genetic

genetic

branching

Japanesereflects

4.

thediagonal)

Table

SEs

affinity

Table

each

overestimatedbranchingon

inclusionofofestimated

Although(figuresdendrogram

distances

loci

Mongoloids

estimatesoferrorsprotein

based

the

in

(average

0.019

gene

estimatesa UPGMA

standard

points

and

141

be

corresponding

because

shows

to

Both

the

those

7
on

to
say,

for

0.16

loci.

is 0.0167•}0.0087.

diversities

and

85

Island-II

gene

0.14

was

Englishin Hainan

(see
Hui

Miao-1,

was

Hui,

UPGMA

dendrogram,

as

seen

in

and

the

Li-Miao

Table

4).

It

excludedJapanese,thenetwork.

group

is possible
from

and

NJ

Hui

the

that
further

has

an

This

than

those

Hui

expe

analysis.

Englishare Dstd and those on the diagonal are gene diversities.

Figuresinparentheses are standard errors. Allele frequency data for 18 polymorphic loci (Hp, Tf, Gc-subtype,C6, C7, Bf, ACP, ESD, 6PGD, PGM1-subtype, GPT, ADA, AK, ABO, MN, Duffy, Kell, andLutheran) were used, and data for 18 monomolphic loci were assumed.

142

SAITOU et al.

Fig. 7. UPGMA dendrogram (A) and NJ network (B) for Li-1, Miao-1, Hui, Japanese, and English.
Dstddistances of Table 4 are used. Open boxes represent 1SE for each branching point of the
UPGMA dendrogram. Each line of the NJ network is proportional to branch lengths(distances).

If we compare the genetic distance (0.0069) between Japanese and Miao-1 andthat (0.0087) between Japanese and Li-1, they are more or less similar with eachother, the average being 0.0078. Thus the divergence time (TJ-ML)between Japaneseand the ancestral population for Miao-1 and Li-1 is estimated in the following way.
Nei and Roychoudhury (1982) estimated the divergence time between Mongoloids(data were mostly taken from Japanese) and English to be 41,000 years, and a more
recent estimate for that is 55,000 years (Nei and Ota, 1991). If the genetic distanceof 0.0167 between Japanese and English (Table 4) corresponds to these divergencetime estimates, that (0.0078) between Japanese and the Miao-Li cluster should
correspond to TJ-ML.Hence the estimate for TJ-ML,under the assumption of theconstant evolutionary rate, becomes 19,000-26,000 years, depending on the estimatesfor divergence time between Mongoloids and English.

Genetic Study in Hainan Island-II

143

DISCUSSION
A possible history of Li, Miao, and Hui populations of Hainan Island
We analyzed the genetic affinity of six human populations living in Hainan Islandin the present study. Two Li populations (Li-1 and Li-2) are always clustered inmost of the trees, suggesting a close genetic relationship of these two populations.
This supports the common origin hypothesis for these two Li populations (Omoto
et al., 1993). A preliminary study on the genetic affinity of Hainan Island as well
as some ethnic minorities in northern China (Omoto et al., 1994) also supported
the close affinity of the two Li populations. Although we studied only two Li
subgroups (Qi-Li=Li-1,
and Benti-Li=Li-2),
it is possible that all the five Li
subgroups started to differentiate after their common ancestral population migrated
into Hainan Island. According to an archaeological evidence, the earliest record ofhuman occupation in this island is about 3,000 years ago (Yu, 1985). We would
like to suggest that the common ancestral population of all the five present day Li
subgroups migrated into Hainan Island from the mainland China around that time.
This hypothesis can also explain the close genetic affinity of Li with Miao andZhuang, who probably have lived in southern part of China for a long time.
Miao tribe in Hainan Island are said to be descendants of migrants from Guangxi
Province of mainland China as early as in the time of Ming dynasty (Omoto et al.,1993). Miao-1 and Miao-2 populations show a relatively large genetic distance andthey do not make a cluster in any tree. Therefore, it is possible that there was morethan one migration of Miao populations to Hainan Island as Omoto et al. (1993)
suggested, and that the original stock of different migrations may be geneticallydifferent from each other. However, an alternative possibility can also explain thepattern observed for Miao populations. If the population size of these two Miao
populations have been kept rather small, the random genetic drift may have causeda large genetic differentiation within a relatively short time even if they initiallyoriginated from the common ancestral population. In fact, the two Miao populations
were clustered in an NJ network of Omoto et al. (1994) in which data for slightly
different set of polymorphic loci were used.
Hui, a moslem group, has a close genetic affinity with Li, Miao, and Zhuang
ethnic minorities of southern China (see Figs. 5 and 6). This relationship is different
from that of Omoto et al. (1994), in which Hui was more closely related withpopulations of East Asia (Japanese, Mongolian, and Korean). When Hui wascompared with Miao-1, Li-1, Japanese, and English for 18 polymorphic loci,however, Hui was shown to have some affinity with Japanese (Table 4 and Fig. 7).
Therefore, it is possible that the ancestral population of Hui migrated from anorthern part of China to Hainan Island, and gene flow from the surrounding
populations of the island took place after the migration. In fact, a majority of Huipopulations is distributed in the northwestern part of China. This northern origin

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SAITOUet al.

hypothesis for Hui of Hainan Island is consistent with Omoto et al.'s (1993)
conjecture that malaria was not endemic in Hui's original homeland. However, it
is still not clear why Hui of Hainan Island speaks a Chamic language which is
spoken by some northern Vietnamese populations.
Relationship of Hainan Island populations with other Asian populations
When six populations of Hainan Island were compared with 12 other populations,those Hainan Island populations showed affinity with Thailanders, Javanese, andZhuang in both UPGMA and NJ trees (Figs. 5 and 6, respectively). This clustering
pattern is consistent with the geographical proximity of the Island with southern partof the mainland China and with Southeast Asia. It should be mentioned, however,that some Southeast Asian populations (Malays and Filipinos) were somewhat
distant from the Hainan Island populations and were more closely related withnorthern East Asian populations (Japanese, Mongolian, and Korean).
There are two studies on the genetic affinity of human populations including someHainan Island populations. Saitou et al. (1992) presented an NJ network for 18 East
Asian populations based on the allele frequency data of HLA-A, B, and C loci. A
close affinity among Li, Miao (in the mainland China), Zhuang, and Han (in Hainan
Island) were observed, and it is consistent with the result of the present study.
Imanishi et al. (1992) analyzed allele frequency data of HLA-A and B loci for 77
populations over the world, and constructed a UPGMA dendrogram and an NJ
network. Li, Miao (in southern mainland China), Thailanders, Vietnamese, Buyi (insouthern mainland China), and southern Chinese showed a close affinity in both
trees. This is also consistent with our present results.
It can be summarized that Hainan Island populations seem to have a closer genetic
affinity with some surrounding populations of southern China and Southeast Asia
than those of northern East Asia.
Genetic differentiation between northern and southern Asian populations
Saha and Tay (1992) showed a UPGMA dendrogram of 9 Asian populations
based on data for 15 polymorphic loci. There was a clear dichotomy of southernand northern East Asian populations in the dendrogram; Korean, Mongolian, andJapanese were included in the northern cluster, while the southern cluster consistedof Southern Chinese, Zhuang, Malays, and Javanese.
A distinct dichotomy of southern and northern populations of East Asia was also
recognized in Saitou et al.'s (1992) NJ network. Li and Han of Hainan Island, Miao,
Yiao, Zhuang, and Dong of southern mainland China as well as Han of Guangxi
and Guangzhou belonged to the southern cluster, whereas Han, Mongolian, Tibetan,
Hazakh, and Hui of northern China as well as Japanese and Korean belonged to
the northern cluster. Imanishi et al.'s (1992) UPGMA dendrogram also showed aGeneticStudy in HainanIsland-II

145

clear distinction between northern and southern populations of East Asia, though
this distinction was not clearly observed in their NJ network. Matsumoto (1987)
reviewed a distribution of allele frequencies for the Gm locus, and there is a clear
difference between northern and southern populations of Asia.
Four northern populations of East Asia (Japanese, Mongolian, Korean, and Ainu)
formed a closely related group in the present study, but the variation among theremaining southern populations was much larger than that for those four northern
populations (see Figs. 5 and 6). It should be remembered that data for only 10
polymolphic loci were used for constructing those trees, and the reliability of the
branching pattern of those trees may not be high.
Cavalli-Sforza et al. (1988) constructed a UPGMA dendrogram for 42 populations
over the world, and showed that populations of northern East Asia such as Japanese,
Ainu, Koreans, Mongolian, and Tibetans are more closely related to Caucasoid
populations than to those of Southeast Asian and southern Chinese. Recently, Nei
and Roychoudhury (1993) analyzed a different set of allele frequency data for 29
polymolphic loci for 26 human populations, and found that northern and southern
Asian populations are more closely related with each other than to Caucasoid bothin UPGMA and NJ trees. The reason for this discrepancy between the two studies
may be that Cavalli-Sforza et al. (1988) used many unshared loci for comparisonand only 5 loci were commonly examined for all 42 populations (Nei andRoychoudhury, 1993). The results of the present study consistently showed a distantrelationship between English (a Caucasoid) and the remaining Asian populations,which supports the result of Nei and Roychoudhury (1993).
If Japanese and the Li-Miao group can be considered as the representatives ofnorthern and southern East Asian populations, estimate of TJ-ML(19,000-26,000
years) corresponds to the divergence time between northern and southern populations.
Although it is a rough estimate, it seems reasonable that at least 10,000 years passed
after the ancestral populations of the present northern and southern populations ofEast Asia diverged.
At last, we would like to note that a unique history of Negritos among the Asian
populations (Omoto, 1984) is also shown in Figs. 5 and 6, where Negritos was
distantly related with all the other East and Southeast Asian populations.
Conclusion
Allele frequency data only for a dozen or so genetic loci were used in the present
study, and a definite conclusion is difficult to extract. Because the amount of genetic
differentiation is so small among the populations of interest, we need a lot more genetic
polymorphism data to elucidate conclusive statements on the genetic affinity of Hainan
Island populations. DNA polymorphism such as VNTR may be the tool for a detailed
analysis of genetic affinity between closely related human populations in the future.

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SAITOUet al.
ACKNOWLEDGEMENTS

The authors thank Drs. K. Aoki and T. Imanishi for their helpful comments. This
study was supported by Grants-in-Aid for Scientific Research (International Scien
tificResearch Program) and for Scientific Research on Priority Areas (Prehistoric
Mongoloid Dispersals) of Ministry of Education, Science and Culture, Japan.
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