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Am J Hum Genet 38:341-351, 1986
Human Mitochondrial DNA Types in Two Israeli
Populations-A Comparative Study at the DNA Level
BATSHEVA BONNETAMIR,' M. J. JOHNSON,2'3 A. NATALI,2 D. C. WALLACE,4
AND L. L. CAVALLI-SFORZA2
Variations in human mtDNA restriction endonuclease fragment patterns
were investigated in a sample number of 81 Israelis-Jews and
Arabs-using total blood cell DNA. Eight new morphs were observed
using five enzymes: HpaI, BamHI, HaeII, MspI, and Avall. Of the 18
different combinations of fragment patterns (mtDNA types), only
three were shared by both groups, but with striking frequency differences.
The Arab sample disclosed "African" characteristics and was
found to be slightly more polymorphic than the Israeli sample. One of
the new types filled a "missing link" originally postulated in a phylogeny
of mtDNA human types.
MATERIALS AND METHODS
Populations
Two distinct groups constituted the population sample: 41 were Arabs picked at
random from several villages in central and northern Israel and 40 were randomly picked
Israeli-born Jews, comprising 35 Ashkenazi origin, three Sephardi, two Yemenite,
and one Iraqi.
DISCUSSION
This study has focused on a comparison of mtDNA polymorphisms in two
population groups living in Israel. The samples are communities that differ in
their ethnic religious affiliations but both represent populations that emerged as
unique peoples, perhaps 5,000-10,000 years ago. Both belong to the same
major ethnic division (Caucasians), but in view of the paucity of the data, no
attempt was made to use these preliminary data for the discussion of evolutionary
trees and divergence times.
Of the five enzymes used in this study, four proved particularly useful and
contributed to the mtDNA variability encountered. BamHI, which generally
generates the least morphs, was the least informative. The numbers of individuals
forming the samples are rather small, yet both populations differ
significantly from the existing Caucasian data in the fragment patterns resulting
from the three restriction enzymes HpaI, Mspl, and HaeII.
Hpal yielded only two morphs (2 and 3). Previously, morph 3 was found only
in African populations [7]. In our study it was confined to the Arab community.
This finding is consistent with earlier studies reporting the presence of typical
"African" markers such as Fy (a-b-), Rho, and Sutter among Arab communities
in Israel [15, 16].
The other enzymes also show a slight tendency toward "African" characteristics
of the Arab population (especially when compared with the Jewish one),
such as the lower Avall morph I frequency, the existence of types 3 and 5, and
the lowered frequency of morph 1 of the MspI enzyme.
The same trend is apparent from the combination of the restriction endonuclease
morphs observed for each individual (table 2). Altogether, 18 distinct
mtDNA types were found, eight of which have been reported earlier [8] and 10
that have not. Of these 18 types, only three are shared by both Israeli groups
and, even then, with striking differences in frequencies.
Type 1 (2-1-1-1-1), which was found to be the most common type in all major
groups, was also the most frequent in our two communities, although less
among the Israeli Jews (38% vs. 56.4%).
Type 6 (2-1-2-22), on the other hand, was rather frequent among the Israeli
Jews (36%)-more common than in all major populations, due to the frequency
of Haell morph 2.
In spite of the fact that the Israeli Jewish sample was composed of representatives
of the Ashkenazi, Sephardi, and Oriental divisions, the Arab sample
seems slightly more polymorphic, perhaps reflecting the contribution of more
numerous ancestral females.
In figure 4, the 10 new mtDNA types have been added to the suggested
phylogeny of the 35 types already described [8]. On the basis of relating the
types through single site changes, more than half of the new patterns radiate
directly from the central and most common type 1 (2-1-1-1-1), two derive from
types belonging to the Caucasian branch, while one type (no. 43) derives from a
branch that forms a distinct African lineage. In order to relate another new type
(no. 36) by minimal number of mutations, a missing intermediate was postulated.
Also, of particular interest was our discovery of a new type (no. 39) that
forms one of the missing intermediates originally postulated to exist between
types 1 and 27.
In spite of the very small numbers in each group, these data demonstrate the
possible existence of group-specific mtDNA fragment patterns and that certain
types may be unique to certain groups. Even in a relatively short evolutionary
time new types appear and may remain unique in populations that are relatively
isolated one from the other. This differentiation process is probably faster with
mtDNA than with nuclear genes that are believed to have a lower mutation
rate.
Obviously, larger sample sizes and representation of members of different
families from more Jewish and Arab communities are needed for confirmation
of these speculations for assessment of the extent of heterogeneity within the
isolated communities and of the degre
Am J Hum Genet 38:341-351, 1986
Human Mitochondrial DNA Types in Two Israeli
Populations-A Comparative Study at the DNA Level
BATSHEVA BONNETAMIR,' M. J. JOHNSON,2'3 A. NATALI,2 D. C. WALLACE,4
AND L. L. CAVALLI-SFORZA2
Variations in human mtDNA restriction endonuclease fragment patterns
were investigated in a sample number of 81 Israelis-Jews and
Arabs-using total blood cell DNA. Eight new morphs were observed
using five enzymes: HpaI, BamHI, HaeII, MspI, and Avall. Of the 18
different combinations of fragment patterns (mtDNA types), only
three were shared by both groups, but with striking frequency differences.
The Arab sample disclosed "African" characteristics and was
found to be slightly more polymorphic than the Israeli sample. One of
the new types filled a "missing link" originally postulated in a phylogeny
of mtDNA human types.
MATERIALS AND METHODS
Populations
Two distinct groups constituted the population sample: 41 were Arabs picked at
random from several villages in central and northern Israel and 40 were randomly picked
Israeli-born Jews, comprising 35 Ashkenazi origin, three Sephardi, two Yemenite,
and one Iraqi.
DISCUSSION
This study has focused on a comparison of mtDNA polymorphisms in two
population groups living in Israel. The samples are communities that differ in
their ethnic religious affiliations but both represent populations that emerged as
unique peoples, perhaps 5,000-10,000 years ago. Both belong to the same
major ethnic division (Caucasians), but in view of the paucity of the data, no
attempt was made to use these preliminary data for the discussion of evolutionary
trees and divergence times.
Of the five enzymes used in this study, four proved particularly useful and
contributed to the mtDNA variability encountered. BamHI, which generally
generates the least morphs, was the least informative. The numbers of individuals
forming the samples are rather small, yet both populations differ
significantly from the existing Caucasian data in the fragment patterns resulting
from the three restriction enzymes HpaI, Mspl, and HaeII.
Hpal yielded only two morphs (2 and 3). Previously, morph 3 was found only
in African populations [7]. In our study it was confined to the Arab community.
This finding is consistent with earlier studies reporting the presence of typical
"African" markers such as Fy (a-b-), Rho, and Sutter among Arab communities
in Israel [15, 16].
The other enzymes also show a slight tendency toward "African" characteristics
of the Arab population (especially when compared with the Jewish one),
such as the lower Avall morph I frequency, the existence of types 3 and 5, and
the lowered frequency of morph 1 of the MspI enzyme.
The same trend is apparent from the combination of the restriction endonuclease
morphs observed for each individual (table 2). Altogether, 18 distinct
mtDNA types were found, eight of which have been reported earlier [8] and 10
that have not. Of these 18 types, only three are shared by both Israeli groups
and, even then, with striking differences in frequencies.
Type 1 (2-1-1-1-1), which was found to be the most common type in all major
groups, was also the most frequent in our two communities, although less
among the Israeli Jews (38% vs. 56.4%).
Type 6 (2-1-2-22), on the other hand, was rather frequent among the Israeli
Jews (36%)-more common than in all major populations, due to the frequency
of Haell morph 2.
In spite of the fact that the Israeli Jewish sample was composed of representatives
of the Ashkenazi, Sephardi, and Oriental divisions, the Arab sample
seems slightly more polymorphic, perhaps reflecting the contribution of more
numerous ancestral females.
In figure 4, the 10 new mtDNA types have been added to the suggested
phylogeny of the 35 types already described [8]. On the basis of relating the
types through single site changes, more than half of the new patterns radiate
directly from the central and most common type 1 (2-1-1-1-1), two derive from
types belonging to the Caucasian branch, while one type (no. 43) derives from a
branch that forms a distinct African lineage. In order to relate another new type
(no. 36) by minimal number of mutations, a missing intermediate was postulated.
Also, of particular interest was our discovery of a new type (no. 39) that
forms one of the missing intermediates originally postulated to exist between
types 1 and 27.
In spite of the very small numbers in each group, these data demonstrate the
possible existence of group-specific mtDNA fragment patterns and that certain
types may be unique to certain groups. Even in a relatively short evolutionary
time new types appear and may remain unique in populations that are relatively
isolated one from the other. This differentiation process is probably faster with
mtDNA than with nuclear genes that are believed to have a lower mutation
rate.
Obviously, larger sample sizes and representation of members of different
families from more Jewish and Arab communities are needed for confirmation
of these speculations for assessment of the extent of heterogeneity within the
isolated communities and of the degre