1022-7954/05/4103- © 2005 Pleiades Publishing, Inc.
Russian Journal of Genetics, Vol. 41, No. 3, 2005, pp. 256–261. Translated from Genetika, Vol. 41, No. 3, 2005, pp. 334–340.
Original Russian Text Copyright © 2005 by Yurenkova, Kubrak, Titok, Khotyljova.
According to a number of authors, the genus
includes more than 20 species [1, 2]. Owing to its cul-
tivation at different latitudes, this genus is fairly poly-
morphic, thus having a complicated and unclear taxon-
omy. In the middle of the 20th century, the systematics
of the genus
was developed on the basis of the
geographical principle of morphological differences,
which are not always taxonomically valuable, and the
ability to yield fertile hybrid progeny [2, 3]. At present,
the evolutionary and systematic relationships and
genetic divergence within this genus have been clariﬁed
using cytological and genetic methods, which include
such modern techniques as C-banding of chromo-
somes, RAPD–PCR analysis, electrophoretic fraction-
ation of seed storage proteins, gas chromatography for
determining fatty acid composition of seed oil, etc.
[1, 2, 4, 5].
Owing to clear and stable isozyme patterns, isozyme
analysis as the most available and generally accepted
approach is used to modify and expand the traditional
methods based on classical genetic markers .
Isozymes have been widely applied in plant gene pool
studies as markers of genetic variation. However, anal-
ysis of polymorphism studies of various isozyme sys-
tems among the members of the
showed that this
line of research has been yet insufﬁciently investigated.
The results of studies in this direction will provide
information on inter- and intraspeciﬁc genetic varia-
tion, evaluate the mechanisms of selection and evolu-
tion processes in
populations, and verify inter-
speciﬁc relationships within this genus.
The aim of the present study was estimating genetic
polymorphism of various ﬂax species by comparative
analysis of isozyme patterns of 6-phosphogluconate
dehydrogenase, glutamate-oxaloacetate transaminase,
and cytochrome-c-oxidase in plant leaves to detect loci
and alleles controlling the isozyme synthesis, as well as
analyzing the fatty acid composition of seed oil as a
MATERIALS AND METHODS
We used the following wild
= 16; pale ﬂax
= 30; blue ﬂax
= 18; and two subspecies of cultivated
L.: ﬁber ﬂax
, cultivar Svetoch,
= 30 and intermediate ﬂax
, cultivar Koto,
= 30, according to the classiﬁcation in .
Polyacrylamide gel (7%) was prepared according to
Davis . For electrophoresis of cytochrome-c-oxidase
and glutamate-oxaloacetate transaminase, green leaves
of plants at the blossoming phase were used; for 6-pho-
phogluconate dehydrogenase, we used greed leaves of
seedlings. Green seedlings were grown in a photo con-
tainer using luminescent lamps LB-40 and illumination
regime 14/10 h (day/night) at 25
C. To prepare enzyme
extracts, the plant material was squashed in a Tris-gly-
cine buffer, pH 8.3, containing 0.005 M EDTA and
-mercaptoethanol. After electrophoresis, gels
were stained using standard procedures adapted for ﬂax
. The results are presented in Figs. 2–4 as zymo-
grams. For more precise description of the results, the
isozyme bands are characterized by relative electro-
phoretic mobilities (
), which are given on the scale at
the left side of each ﬁgure.
Fatty acids were extracted and identiﬁed using a
procedure by Welch  with our modiﬁcations.
Ground seeds (6 to 8 mg) were placed in a 2% sulfuric
acid solution in absolute methanol containing margaric
Flax Species Polymorphism
for Isozyme and Metabolic Markers
S. I. Yurenkova, S. V. Kubrak, V. V. Titok, and L. V. Khotyljova
Institute of Genetics and Cytology, National Academy of Sciences of Belarus, Minsk, 220072 Belarus;
fax: (172)84-19-17; e-mail: email@example.com
Received December 15, 2003
—Genetic diversity of ﬂax isozyme patterns of 6-phosphogluconate dehydrogenase, glutamate-oxalo-
acetate transaminase, and cytochrome-c-oxidase in leaves, as well as the level and the relative amounts of fatty
acids in seed oil were studied in ﬂax species. The isozyme loci examined were found to be polymorphic. It was
shown that each of the ﬂax species studied was characterized by strictly deﬁned amounts and proportions of
fatty acids, i.e., the fatty acid composition of the seed oil may be used as a species diagnostic trait. Our results
suggest that all of the ﬂax species studied have the same ancestor.
was shown to be a phy-
logenetic branch split at an early stage of the ﬂax evolution.