1022-7954/05/4105- © 2005 Pleiades Publishing, Inc.
Russian Journal of Genetics, Vol. 41, No. 5, 2005, pp. 509–517. Translated from Genetika, Vol. 41, No. 5, 2005, pp. 635–645.
Original Russian Text Copyright © 2005 by Brykov, Polyakova, Podlesnykh, E. Golub’, A. Golub’, Zhdanova.
Genetic differences among populations are caused
by random processes and (or) natural selection, when
the gene exchange among the populations completely
or partially stops. The magnitude of genetic variation
among populations is usually directly associated with
the level of restriction of genetic material exchange
among populations and the time of their independent
existence [1–4]. In most cases, the genetic differences
increase with increasing geographical distance between
these populations . The role of barriers limiting the
among-population gene exchange is clearly manifested
upon comparison of genetic variability in freshwater,
anadromous, and marine ﬁsh. In freshwater ﬁsh spe-
cies, whose populations are limited by river or lake sys-
tems and isolated from other populations by physical
barriers, a substantial part of genetic variation is
accounted for by the interpopulation component [2, 5].
Many marine ﬁsh species have a motile larval stage or
spawn that can move to large distances with currents.
Owing to migration of ﬁsh (and thus genetic material)
over the species range, population subdivision in these
species is generally insigniﬁcant, resulting in a low pro-
portion of interpopulation genetic variability [1–5].
In anadromous ﬁsh species, including sockeye
, part of the life cycle is the
feeding period in the sea, where individuals of different
origin mix freely. Led by homing instinct, most ﬁsh
return for spawning to their native freshwater rivers and
lakes. This biological feature signiﬁcantly hinders gene
exchange among ﬁsh from different populations [4, 6].
As a result, interpopulation component of genetic vari-
ability in these species is rather high [1–5, 7].
In the present work, we examined mitochondrial
DNA (mtDNA) variation to compare sockeye popula-
tions from three Chukotka and Kamchatka lake–river
systems located far apart.
MATERIALS AND METHODS
The map of the three lake–river systems is presented
in Fig. 1.
Sockeye salmon from Azabach’e Lake.
This lake is
situated on northwestern Kamchatka Peninsula and is
linked by a canal with the Kamchatka River. The sock-
eye spawning grounds of Azabach’e Lake are classiﬁed
into three types: river (Bushueva River and Lotnaya
River), lake spawning sites on creek bowls (Atkhl,
Rybovodnyi II; in the present study, these samples were
pooled as they are practically identical  and denoted
as Azabach’e springs), and a littoral spawning site near
the Kultuchnaya River mouth (hereafter referred to as
Kultuchnoe). Sockeye spawning occurs in two stages.
The mid–late July is the time of reproduction of the
early (spring) race (Atkhl, Rybovodnyi II, Lotnaya),
whereas the late (summer) race typically spawns in
mid-August through mid-September (Kultuchnoe,
Bushueva River) .
Sockeye salmon from Kuril’skoe Lake (southwest-
ern Kamchatka) does not show temporal subdivision of
The Effect of Reproduction Biotopes
on the Genetic Differentiation of Populations
of Sockeye Salmon
Vl. A. Brykov
, N. E. Polyakova
, A. V. Podlesnykh
, E. V. Golub’
A. P. Golub’
, and O. L. Zhdanova
Institute of Marine Biology, Russian Academy of Sciences, Vladivostok, 69004 Russia;
fax: (4232) 31-09-00; e-mail: firstname.lastname@example.org
Department of Biochemistry and Biotechnology, Far Eastern State University, Vladivostok, 690000 Russia
Chukotka Research Institute of Fisheries and Oceanography (ChukotNIRO), Anadyr’, 689000 Russia
Institute for Automation and Control Processes, Russian Academy of Sciences, Vladivostok, 690041 Russia
Received May 11, 2004
—Variation of mitochondrial DNA (mtDNA) was examined in nine populations from three lake–river
systems of Chukotka and Kamchatka. Signiﬁcant differences were found between most of the sockeye salmon
samples studied. The genetic differences among populations were not high and often did not correlate with the
geographical distances between them. The low population divergence is explained by a short time of existence
of most of them, having been formed after the recession of the upper Pleistocene glacier. When the populations
were grouped according to their spawning biotopes (river or lake), they in general appeared more genetically
similar than upon their grouping by geographical location (the lake–river systems). The differences between the
river and lake populations in the lake–river systems increased from north to south.