1022-7954/02/3801- $27.00 © 2002
Russian Journal of Genetics, Vol. 38, No. 1, 2002, pp. 44–49. Translated from Genetika, Vol. 38, No. 1, 2002, pp. 56–62.
Original Russian Text Copyright © 2002 by Utevskaya, Atramentova.
Treatment of diseases with medicinal leeches,
known from the ancient times, in recent decades has
acquired scientiﬁc grounds becoming a tool of modern
medicine. Leeches are most commonly used for treat-
ing cardiovascular disorders. The method is also
applied to some ophthalmic, articular, neurological,
stomatological, gynecological, and urological diseases;
most recently, it was successfully used in restorative
surgery. Highly puriﬁed components of leech salivary
gland secretion are used in production of pharmaceuti-
cals and cosmetics [1–7].
Medicinal leeches occur in Europe and Asia and
inhabits small stagnant and slow-current water reser-
voirs. They feed on the blood of members of all verte-
brate classes. During blood-sucking, leeches release the
salivary gland secretion into the victim’s blood. The
secretion contains biologically active compounds,
which are responsible for the effect of leech treatment.
are hermaphroditic. Under natural
conditions, they reach maturity in the second or third
year of life and reproduce once a year. After mating,
leeches lay several cocoons, which contain on average
10–15 juveniles [2, 3, 8–11].
Application of leeches in medicine and drug indus-
try is badly hampered by the reduction in their popula-
tion in natural basins. The species
is threatened by extinction. It has been entered in the
European Red List and Red Data Books of many Euro-
pean countries. For this reason and became of sanitary
standards only leeches bred in aquaculture are used for
Leech genetics is poorly known. Its studies dealt
mainly with karyology and concerned leech evolution,
systematics , and molecular genetics, which was
related to obtaining recombinant components of leech
salivary gland secretion [13, 14]. Until recently, no
studies were dedicated to population genetics or breed-
ing of the leech, and studies on increasing the produc-
were conﬁned to their mainte-
nance [15–23]. Improvement of leech genetics requires
knowledge of the structure of artiﬁcially grown popula-
tions. In view of this we present an analysis of reproduc-
tive traits in an artiﬁcial
MATERIALS AND METHODS
The study was performed on a random mating
laboratory population. The
following reproductive traits were investigated: batch
size (the number of cocoons), the number of juveniles
per cocoon, and juvenile weight. Batch size and the
number of juveniles per cocoon were considered to
determine the general fecundity, and juvenile weight, as
an index of offspring quality.
The number of cocoons laid by each leech and the
number of juveniles in each cocoon were counted.
Younglings were weighed after hatching from the
cocoons and after the ﬁrst feeding. The surviving youth
were counted after six months.
We investigated 386 families, including 231
batches, 734 cocoons, and 5131 juveniles. Relations
between full sibs, polyzygous twins, fraternal twins,
parents, and offspring were taken into account.
Heritability of Reproductive Traits
in the Medicinal Leech
O. M. Utevskaya and L. A. Atramentova
Department of Genetics and Cytology Karazin Kharkov National University, Kharkov, 61077 Ukraine;
fax: (0572)47-18-16; e-mail: email@example.com
Received February 14, 2001; in ﬁnal form, August 21, 2001
—The phenotype variability and inheritance of reproductive traits were investigated in the medicinal
leech. Distribution parameters were determined for the following traits: batch size (
), number of juveniles in a cocoon (
), and juvenile weight (
). A nonlinear negative correlation between the number of juveniles in a cocoon and their
weight was found (correlation ratio
= 0.86). It was shown that the environmental variance dominated over the
genotypic one in the structure of phenotypic variance of the traits studied. The genetic variability is determined
mainly by additive gene interactions and, to a small extent, intralocus dominance. The narrow-sense heritability,
, for batch size was 0.35–0.40; for the number of juveniles in a cocoon, 0.35; for juvenile weight, 0.42.