1022-7954/03/3908- $25.00 © 2003
Russian Journal of Genetics, Vol. 39, No. 8, 2003, pp. 849–859. Translated from Genetika, Vol. 39, No. 8, 2003, pp. 1013–1025.
Original Russian Text Copyright © 2003 by Bermisheva, Viktorova, Khusnutdinova.
Numerous polymorphic loci identiﬁed in the course
of human genome sequencing serve as a powerful tool
for analysis of the pool structure, dynamics, history,
and geography of the human gene pool. All markers
used in the population studies can be divided into three
groups, i.e., autosomal markers, mitochondrial DNA
(mtDNA) and Y-chromosome markers. Polymorphism
of these markers is determined by factors of microevo-
lution (migration, selection, gene drift, and mutation).
Their variability, however, differently reﬂects the
effects and the outcomes of these processes. Analyses
of mtDNA and Y-chromosome variation provide previ-
ously unavailable possibilities: to trace and compare
the histories of the male and female population parts
and evaluate their contribution to the population gene
This review is focused on the analysis of the oppor-
tunities provided by the mtDNA polymorphism for
solving problems of different evolutionary scale: from
the reconstruction of the earliest human evolution and
spreading of modern humans to analysis of genetic dif-
ferentiation of closely related extant populations.
SPECIFIC FEATURES OF mtDNA
The results of intensive studies of human mitochon-
drial genome organization and functioning have been
widely used in population and evolutionary genetics.
Human mtDNA is a 16 569-bp circular molecule
located in the mitochondrial matrix. Each mtDNA mol-
ecule codes for 13 polypeptides, which are the compo-
nents of the oxidative phosphorylation system. It also
contains the genes for two ribosomal and 22 transport
RNAs. The mtDNA genes lack introns; they are sepa-
rated by intergenic spacers one to several nucleotides in
size (Fig. 1). Human mitochondrial gene pool is highly
polymorphic. Several features of mtDNA deserve spe-
(1) Human mtDNA has been shown to be inherited
strictly maternally , and hence, in contrast to auto-
somes, it does not obey the rules of Mendelian inherit-
ance. Phylogeny of human mtDNA is a phylogeny of
human maternal lineages. The mechanism of elimina-
tion of paternal mtDNA is not quite clear but some facts
about it are known. First, the number of mitochondria
in the oocyte is hundreds of times higher than in the
sperm cell . This fact alone imposes limitations on
paternal inheritance. In addition, Kaneda
described elimination of paternal mtDNA in the intraspe-
ciﬁc crosses in mice.
(2) Lack of recombination between the mtDNA
molecules provides evolution of mitochondrial genome
at the expense of mutations accumulated in subsequent
generations . The existing linkage disequilibrium
between mitochondrial mutations makes it possible to
consider the mtDNA molecule as a single locus, repre-
sented by numerous alleles (mitotypes), certain groups
of which correspond to the linkage groups between cer-
tain mutations. This speciﬁc feature of mtDNA turned
out to be very useful for studies of molecular evolution,
since, due to mutation associations, the mitochondrial
gene pool diversity keeps a great number of combina-
tions of mutations. This makes it possible dating of
mtDNA changes and classifying molecular alterations
in relation to the evolution of the populations.
(3) Maternal mode of inheritance and the lack of
recombination  make effective population size (
of mitochondrial genome much smaller than any auto-
somal locus of the nuclear genome. Smaller
increases sensitivity of mtDNA diversity to changes in
population size (genetic drift), but, at the same time,
makes it possible to determine the existence of a bottle-
neck, which is not evident from the analysis of nuclear
marker frequencies, for which the
is three (X-chro-
mosome) or four times higher.
(4) Somatic cells contain from 10
dria. Their genomes can be identical (homoplasmy).
Another variant is heteroplasmy, when a cell contains
Polymorphism of Human Mitochondrial DNA
M. A. Bermisheva, T. V. Viktorova, and E. K. Khusnutdinova
Institute of Biochemistry and Genetics, Russian Academy of Sciences, Ufa, 450054 Bashkortostan, Russia;
fax: (3472)35-61-00; e-mail: firstname.lastname@example.org
Received May 14, 2001; in ﬁnal form, September 10, 2002
—To date, a large data set on the mitochondrial DNA (mtDNA) sequence variation in human popula-
tions has been accumulated. The use of direct sequencing of the main noncoding region of mtDNA along with
the RFLP analysis provide performance of complex analysis of mtDNA polymorphism in human populations.
This approach proved to be effective for obtaining molecular genetic portraits of the world populations, as well
as for the elucidation of the human evolutionary history and past migrations.