genetic heterogeneity among the negroid and arab tribes of the sudan
TRANSCRIPT
AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY 76:211-215 (1988)
Genetic Heterogeneity Among the Negroid and Arab Tribes of the Sudan
JOHN S.H. TAY AND N. SAHA Departments of Paediatrics (J.S.H.T.) and Biochemistry (N.S.), Faculty of Medicine, National Uniuersity of Singapore, Singapore 051 1
KEY WORDS Genetic distances, Sudan
ABSTRACT Genetic distance analysis was carried out among seven tribes of the Sudan comprising three Negroid (Nuba, Fur, and Nilotes) and four Arab tribes (Beja, Gaalin, Hawazma, and Messeria) on the basis of six polymorphic loci (ABO and Rhesus blood groups; haemoglobin and red cell glucose-6-phos- phate dehydrogenase; serum haptoglobin and transfenin polymorphisms) con- trolling 21 alleles and compared with the Arab and Negroid populations in neighbouring countries. The Nuba and Nilotes have been found to have Negroid genetic characteristics, while the Fur are intermediate between the Arabs and Negroids. The Beja and Gaalin tribes have more pronounced Arab genetic char- acteristics than the Hawazma and Messeria, who have a great deal of Negroid admixture.
The population of the Sudan is composed of many endogamous tribes of either original Negroid or mixed Arab-Negro ancestry. The aboriginal Negroid tribes include the Nil- otes, Nuba, and Fur, while the Gaalin, Ha- wazma, Messeria, and the Beja are some of the important Arab tribes. The Nilotes have been studied for the distribution of blood groups by Roberts et al. (1955). A detailed study of blood genetic markers in Beja of the northeastern Sudan was carried out by El Hassan et al. in 1968. We have been re- porting on the blood genetic markers of the remaining tribes over the last few years (Bayoumi et al., 1985; Bayoumi and Saha, 1987; Saha and El Sheikh, 1987). In addition to these, we earlier reported on the blood genetic markers of four tribes (two Arab and two mixed) of western Saudi Arabia (Bay- oumi et al., 1979; Saha et al., 1980) and of the Bedouin and non-Bedouin Arabs of Jor- dan (Banerjee et al., 1981; Saha and Baner- jee, 1986).
It is interesting to study the extent of ge- netic heterogeneity among these Sudanese tribes by genetic distance analysis and re- late this to the Saudi Arabian tribes, Jordan Arabs, and some African Negroid tribes like Sadawe and Nyaturu of Tanzania (Godber et al., 1976).
In this communication we present the re- sults of genetic distance analysis of the above
populations as a summary of the studies car- ried out on blood genetic markers in the re- gions. The selection of the populations was based mainly on the availability of distinct population groups, comparability of the ge- netic markers studied, and the ethnological background of the above Sudanese tribes.
MATERIALS AND METHODS
Genetic distance analysis was performed on the basis of six polymorphic loci: ABO (p,q,r), Rhesus blood groups (Rl, R,,Ro,r,r”), haemoglobin (Hb*,HbS,Hbo) and red cell glucose-6-phosphate dehydrogenase (A +,B +, BmT,A-,B-,Gd-), serum haptoglobin (Hpl, Hp?, and transferrin polymorphisms ( T f c , ITD). Altogether seven Sudanese tribes (Nuba, Fur, Nilotes, Gaalin, Hawazma, Mes- seria, and Beja), four tribes from western Saudi Arabia (Harbi, Ghamdi, Mograbi, and Mowallad), Bedouin and non-Bedouin Arabs of Jordan, and two tribes from Tanzania (Sandawe and Nyaturu) were included in the study. The details of these populations have been described in various previously pub- lished papers, and their locations are shown in Figure 1. The Nuba, Fur, and Nilotes are
Received April 28, 1987; accepted December 14, 1987. Address correspondence to N. Saha, Department of Biochem-
istry, Faculty of Medicine, National University of Singapore, Lower Kent Ridge Road, Singapore 0511.
0 1988 ALAN R. LISS, INC.
212 J.S.H. TAY AND N. SAHA
Fig. 1 Map showing the locations ofthe populations stud- led. Numbers 1 to 15 represent 15 populations as follows: 1, Nuba; 2, Fur; 3, Nilotes; 4, Gaalin; 5, Hawazma; 6, Messeria; 7, Beja of the Sudan; 8, Harbi; 9, Ghamdi; 10,
Mograbi; 11, Mowallad of western Saudi Arabia; 12, Bed- ouin Arabs of Jordan; 13, non-Bedouin Arabs of Jordan; 14, Sandawe of Tanzania; and 15, Nyaturu of Tanzania.
original Negroid tribes of the Sudan. The Gaalin, Hawazma, and Messeria are the Negro-Arab mixed tribes of the Sudan col- lectively known as Arab Baggara. The Beja are linguistically Cushitic, a different branch of Afro-Asiatic. Historically the Beja arrived in the eastern Sudan probably from the Sa- haran region some 4,000 years before the Arab Baggara. Both the Harbi and Ghamdi are indigenous Arab Bedouins of western Saudi Arabia, while the Mograbi are immi- grants from north Africa, and Mowallad are
an admixed Negroid immigrant tribe who came from black Africa. The Nyaturu of Tan- zania are a Bantu-speaking tribe, while the Sandawe are a Khosian-speaking tribe. The selection of the populations was based mainly on the tribal definition of the population and the comparability of the blood genetic mark- ers available. These criteria limited the choice of the populations from the neighboring countries a great deal. Most of the data on genetic markers used originated in our own laboratory. Rhesus blood group frequency of
GENETIC HETEROGENEITY IN THE SUDANESE 213
Bedouin Arabs Non- Bedouin Arabs G hamd i Gaalin Beja Harbi
~~~~~~d
Fur Hawazma Messe r i a N i totes Sandawe Nuba Nyaturu
?=!= --r[----
-
I I I I I I 1 I
.!5 . 4 .3 . 2 .1 o Genetic distance . 7 . 6
Fig. 2 Dendrogram for the 15 populations of the Sudan and neighboring countries as judged from genetic distance based on six polymorphic loci.
the Nilotes was taken from the paper of Rob- erts et al. (1955) and the Beja data from that of El Hassan et al. (1968). The data of God- ber et al. (1976) on Tanzanian tribes were used for comparison with African Negroid tribes.
Genetic distances among these popula- tions were computed by the method of Cav- alli-Sforza and Edwards (1967). The distance matrix was subjected to a cluster analysis by the minimum-variance method. (Ward, 1963).
RESULTS AND DISCUSSION
Table 1 shows the gene frequencies of 21 alleles controlled by six loci in 15 popula- tions. The genetic distances matrix among the population studied is presented in Table 2 and the cluster dendrogram in Figure 2. In aggregate we observed two major clusters of populations in addition to an outlier, the Nyaturu, a Bantu-speaking tribe from Tan- zania. One major cluster includes altogether
eight tribes, comprising three subclusters formed by i) Bedouin and non-Bedouin Ar- abs of Jordan and Ghamdi tribe of western Saudi Arabia; ii) the Gaalin and Beja tribe of Sudan and Harbi ofwestern Saudi Arabia; and iii) the Mograbi and Mowallad tribes of western Saudi Arabia. The first two clusters are of Asian origin, while the third cluster is of non-Asian (?) origin.
The other major cluster is composed of two subclusters: i) one is formed by the Fur and two supposedly Arab tribes (Hawazma and Messeria) of the Sudan; ii) the other is rep- resented by the Nilotes and Nuba of the Su- dan along with Sandawe of Tanzania. The later cluster is of Negroid nature, while the former cluster represents mainly Asian and non-Asian Caucasoid elements.
The genetic distance analysis among these Sudanese and neighboring populations con- firms our earlier assertion of the purer Arab characteristics of Jordanian Arabs, Negroid admixture of western Saudi Arabs (Harbi),
TAB
LE 1
. Gene fr
eque
ncie
s for
sel
ecte
d Su
dnae
se tr
ibes
and
thei
r ne
ighb
ouri
ng A
rab
and
Neg
roid
trib
es'
Nn
n-
-.I__
Bed
ouin
B
edou
in
Nub
a Fu
r N
ilote
s G
aalin
H
awaz
ma
Mes
seri
a B
eia
Har
bi
Gha
mdi
M
omab
i M
owal
lad
Ara
bs
Ara
bs
Sand
awe
Nva
turu
ABO n P 9 r
Rhe
sus
n R' R2 R"
r i'
n H
apto
glob
in
HP'
H
P2
Transferrin
n $
Her
nogl
o bin
n H
bA
Hbs
Hb
'
phos
phat
e de
hydr
ogen
ase
n MA
'
Glu
cose
-6-
137
49
,183
,1
83
.lo6
,109
,7
12
,709
137
203
,000
,0
95
.029
,0
27
,898
,5
63
.051
,3
16
.022
,0
00
116
145
.371
,4
63
A29
,5
37
116
145
.948
,9
00
,052
,1
00
297
182
1.00
0 .9
37
,000
,0
62
.ooo
,000
297
115
,071
,1
13
,886
,7
48
.003
,0
00
47
,120
,1
68
,712
206
,025
,0
00
,759
,2
16
,000
100
50
0
,500
100
,960
,0
40
87
,994
,006
,000
87
,057
,8
85
,023
164
,170
,1
38
,691
147
,214
,0
78
.465
,2
42
,000
229
,402
,5
98
229
,943
,0
57
373
.985
.0
09
,005
405
,047
,9
23
,007
43
,224
,1
13
,664
38
,197
,0
26
,547
,2
29
,000
132
.426
,5
74
118
,962
,0
38
177
,870
.1
22
,008
69
,159
,6
67
.029
.0
14
nnn
145
,217
,1
46
,637
141
.160
,0
71
,564
,2
06
,000
86
.443
,5
57
86
,855
,1
45
139
,885
,111
,004
85
,047
.7
29
.059
,0
00
,059
100
,193
,0
83
,723
100
.270
.0
85
,428
,2
17
,000
97
.495
,5
15
99
,990
,0
10
100
1.00
0 ,0
00
,000
100
.060
,940
.oo
o .o
n0
42
,190
,1
47
,655
35
,371
,1
00
,264
,2
64
,000
60
,417
,5
83
46
.946
,0
54
75
1.00
0 ,0
00
,000
59
.017
,9
66
,000
43
,187
,0
92
.715
39
,487
,1
92
,149
,1
71
,000
62
,419
,5
81
33
,985
,0
15
61
,967
,0
33
,000
62
,016
,7
74
.161
51
,138
.1
49
.714
45
,366
,0
82
,174
,3
39
,028
55
,330
,6
70
39
,974
,0
26
70
,979
.0
21
.ooo 53
,151
,7
73
,000
,000
25
,201
.l
o7
,693
22
,273
,0
47
,436
,1
55
.089
44
,318
,6
82
35
,971
.0
29
51
,980
.0
20
,000
47
,085
,8
09
,021
,0
00
,000
108
.220
,1
46
,634
109
.406
,1
33
,162
,2
56
,044
109
,326
,6
74
111
,996
,0
04
115
1.00
0 ,0
00
,000
115
,026
,8
96
.009
412
.228
,1
52
,614
408
,412
,1
40
,101
.3
00
,014
119
.324
,6
76
120
.996
,0
04
148
1.00
0 ,0
00
,000
148
.007
,9
26
,020
nn
n nn
n
215
I71
,1
29
,700
215
,035
,0
51
,707
.2
07
,000
184
,639
,3
61
212
.953
,0
47
218
,986
,0
14
,000
156
,090
,8
59
.ooo
217
.173
.1
12
,715
214
075
,047
,7
60
.118
,0
00
175
569
,431
214
.984
,0
16
216
.963
,0
37
,000
114
,105
,7
89
.om
,0
00
,017
,0
11
,007
...
,000
,0
00
__
. ...
,000
,0
00
.020
,0
09
,011
.0
02
. - - -
,0
00
,000
.oo
o ,0
00
,000
.oo
o ,0
00
,000
,0
20
,113
,0
11
.012
,1
30
,106
,0
00
,017
.0
48
,075
,0
85
,069
.0
47
,051
,1
05
-
'Sou
rces
: Nub
a, F
ur, N
ilote
s (ex
cept
Rhe
sus)
, Gaa
lin,
Haw
azrn
a an
d M
esse
ria-
Saha
an
d E
l Sei
kh (1
987)
; Nilo
tes
(Rhe
sus)
-Rob
erts
et
al.
(195
5); B
eja-
El
Has
san
et a
l. (1
968)
; H
arbi
, Gha
rndi
, Mog
rabi
and
Mow
alla
d-Sa
ha
et a
l. (1
980)
; Bed
ouin
and
Non
-Bed
ouin
Ara
bs-B
aner
jee
et a
l. (1
981)
, Sah
a an
d B
anej
ee, (
1986
); Sa
ndaw
e an
d N
yatu
ru-G
odbe
r et
al.
(197
6).
GENETIC HETEROGENEITY IN THE SUDANESE 215
and the Negroid characteristics of the Fur, Nuba, Hawazma, and Messeria tribes of the Sudan. A separate cluster of the Mograbi and Mowallad tribes of western Saudi Ara- bia is not surprising, as they are immigrants from Africa.
The only unexpected result of the genetic distance analysis is that of the Hawazma and Messeria tribes of the Sudan, who claim an Arab origin. The sample sizes of these two tribes are adequate and it appears that they have a greater degree of Negroid ad- mixture than the other Arab tribes of Sudan.
It may therefore be concluded that there is a great degree of genetic heterogeneity among the Arab tribes of the Sudan with a variable extent of Negroid admixture, while the indigenous Negroid tribes (Nuba, Nil- otes) are characteristically Negroid in na- ture. The Fur, though an indigenous Negroid tribe, have acquired a high proportion of Arab genes, probably as a result of intermarriage.
LITERATURE CITED Banerjee, B, Saha, N, Doud, ZF, Khalaf, FH, and Qudah,
H, (1981) A genetic study of the Jordanians. Hum. Hered. 31:65-69.
Bayoumi, RA, Omer, A, Samuel, APW, Saha, N, Sebai, AZ, and Sabaa, HMA (1979) Haemoglobin and eryth- rocyte glucose-6-phosphate dehydrogenase variants among selected tribes of western Saudi Arabia. Trop. Geogr. Med. 31 945-252.
Bayoumi, RA, Taha, TSM, and Saha, N (1985) A study of some genetic characteristics of the Fur and Baggara tribes of the Sudan. Am. J. Phys. Anthropol. 67363- 370.
Bayoumi, RA, and Saha, N (1987) Some genetic markers of the Nuba and Hawazma tribes of Western Sudan.
Cavalli-Sforza, LL, and Edwards, AWF (1967) Phyloge- netic analysis: Models and estimation procedures. Am. J. Hum. Genet. 19233-257.
El Hassan, AM, Godber, MG, Kopet, AC, Mourant, AE, Tills, D, and Lehmann, H (1968) The hereditary blood factors of the Beja of the Sudan. Man 3:272-283.
Godber, MG, Kopec, AC, Mourant, AE, Teesdale, P, Tills, D, Weiner, JS, El-Neil, H, Wood, CH, and Barley, S (1976) The blood groups, serum groups, and red cell isoenzyme and haemoglobin of the Sandawe and Nay- aturu of Tanzania. Ann. Hum. Biol. 3:463-470.
R~berts, DF, Ikin, AE, and Mourant, AE (1955) Blood groups of the Northern Nilotes. Ann. Hum. Genet. 20:135-154.
Saha, N, and Banerjee, B (1986) A study of some blood genetic characteristics of Bedouin and non-Bedouin Ar- abs of Jordan. Hum. Hered. 36276-280.
Saha, N, Bayoumi, RA, El Sheikh, FS, Samuel, APW, El Fadil, I, El Houri, IS, Sebai, ZA, and Sabaa, HMA (1980) Some blood genetic markers of selected tribes of West- ern Saudi Arabia. Am. J . Phys. Anthropol. 52595400.
Saha, N, and El Sheikh, FS (1987) Some blood genetic characteristics of several Sudanese tribes. Am. J. Phys.
Ward, JH (1963) Hierarchical grouping to optimize an
Am. J. Phys. h t h p o l . 73:379-388.
Anthmpol. 73:397-406.
objective function. J . Am. Stat. Assoc. 58236-244.