1067-4136/02/3302- $27.00 © 2002
Russian Journal of Ecology, Vol. 33, No. 2, 2002, pp. 86–91. Translated from Ekologiya, No. 2, 2002, pp. 97–102.
Original Russian Text Copyright © 2002 by Sannikov, Petrova, Semerikov.
One of the key problems in population biology
(including that of woody plants) concerns the extent
of intraspeciﬁc chorogenetic differentiation in natural
populations, especially within a continuous range
(Wright, 1962; Stern and Roche, 1974; Timofeeff-
, 1977; Altukhov, 1983; Yablokov,
, 1988; Goncharenko
Sannikov, 1993; Podgornyi, 1995; Altukhov
1996). In some coniferous tree species, the clinal mode
of interpopulation variation in the genetic structure was
revealed against the background of generally insigniﬁ-
cant genetic differentiation of their populations within
the range (Critchﬁeld, 1985; Yeh
, 1986; Kru-
, 1989, 1990; Semerikov
, 1993; Gon-
, 1995a; Krutovskii and Bergmann,
1995). In conventional comparative biogeographic
studies on the genetic structure (with large intervals
between samples from geographically distant parts of
the range), no signiﬁcant divergences in the genogeo-
graphic structure of populations were found (Semer-
ikov, 1991; Goncharenko
, 1994, 1995b).
To reveal and quantitatively evaluate the chorologic
changes in the gene pool, we proposed the method of
genetic distance gradients (GDGs), which are deter-
mined as the ratio of Nei’s genetic distance (Nei, 1972,
1978) between two populations to the actual distance
between them (Petrova and Sannikov, 1996). This
approach, which has been tested in earlier studies (San-
, 1997; Petrova
, 1989, 2000), provides
the possibility of quantitatively evaluating the rate of
changes in the chorogenetic structure of populations in
the real geographical space.
The purpose of this study was to demonstrate the
efﬁciency and informativeness of the GDG method of
geno- and phenogeographic analysis. As an example,
the transzonal proﬁle of pine forests in the Transural
region and Northern Turgai was used.
MATERIAL AND METHODS
In the Transural provinces of Western Siberia and
Northern Turgai, there is an almost strictly meridional
series of pine forests extending over 1500 km from the
northern boundary of the
L. range in the
pre-forest-tundra subzone (the Synya River basin) to its
southern boundary in the southern steppe (the Naur-
zumskii forest). The forests are conﬁned to the uniform
geomorphological facies of sandy ﬂoodplain terraces.
Taking into account the extremely ﬂat megarelief of
Western Siberia and latitudinal orientation of landscape
zones in this region of Western Siberia, this series of
pine forests is a unique biogeographic phenomenon and
an ideal object for gradient ecogeographic studies.
Figure 1 shows how 12 population samples used for
isozyme analysis were distributed along the transect.
Geno- and Phenogeographic Analysis of
Populations along the Transect Extending from the Northern
to Southern Boundary of the Species Range
S. N. Sannikov
, I. V. Petrova
, and V. L. Semerikov
Botanical Garden, Ural State University, ul. Vos’mogo Marta 202, Yekaterinburg, 620144 Russia
Institute of Plant and Animal Ecology, Ural Division, Russian Academy of Sciences,
ul. Vos’mogo Marta 202, Yekaterinburg, 620144 Russia
Received April 18, 2001
—Nei’s genetic distances (Nei, 1972, 1978) between 12 Scotch pine (
were determined using isozyme analysis. The gradients of these distances along the 1500-km meridional
transect in the Transural Region and Northern Turgai from the pre-forest-tundra subzone (the Synya River
basin) to the southern steppe (the Naurzumskii forest) were calculated. We discovered that the genetic distance
gradients (GDGs) progressively increase in the direction from the northern boundary of the range to the south-
ern boundary of the forest-steppe zone and sharply increase in the insular forests growing in the steppe zone.
The results of cluster analysis and Mahalanobis distance gradients with respect to a set of morphological char-
acters of the cones provide evidence that Scotch pine populations of the forest zone share somewhat the same
gene pool, whereas the group of Scotch pine populations in the insular forests of Northern Turgai is obviously
differentiated phenogenetically from the insular forests of the Tobol region, which grow farther to the north.
Scotch pine, population, genetic differentiation, genetic distance, genetic distance gradient, pheno-
typic differentiation, genogeography, phenogeography.