ISSN 10227954, Russian Journal of Genetics, 2010, Vol. 46, No. 10, pp. 1152–1153. © Pleiades Publishing, Inc., 2010.
Original Russian Text © A.E. Vedernikov, T.V. Anan’ina, A.A. Kokhanenko, V.N. Stegniy, 2010, published in Genetika, 2010, Vol. 46, No. 10, pp. 1305–1306.
Nurse cell chromosomes become polytene during
development in species of the family Calliphoridae.
The polytenization is associated with consecutive
morphological changes in chromatin structure; i.e.,
original reticular nuclei pass through several steps of
the formation of polytene chromosomes, and bloblike
chromosomes appear initially and are followed by the
formation of a secondary reticular chromatin structure
The sex chromosome is the only exception, pre
serving its integral structure unchanged throughout
the polytenization and even after the secondary retic
ular structure is formed in the nucleus. It is clear that
this behavior is due to a unique chromatin structure
and, primarily, by the presence of specific DNA
sequences. To check this hypothesis and to identify
chromosome homologies in closely related species, a
DNA library of the
(Diptera: Calliphoridae) sex chromosome was hybrid
ized in situ to the chromosomes of
RD (Diptera: Calliphoridae) nurse cells.
The fluorescently stained preparation were exam
ined, and a signal from a DNA probe originating from
sex chromosome was detected on
sex chromosome (Fig. 1c). The cen
tral region of the sex chromosome has a narrowing and
a denser chromatin structure in both of the species.
Peripheral chromatin is unwound to form a fan
shaped structure and has a looser structure. Signals
were absent from the other chromosomes.
The result indicates that there are common DNA
chromosome 6 and the
sex chromosome (Figs. 1a, 1c), suggest
ing evolutionary conservation for the corresponding
genome region. It is possible that the sex chromosome
regions common for the two different species contrib
ute to the maintenance of the structure of these chro
mosomes during nurse cell development.
To identify the homologous sequences in other
close species, the chromosomes of
(Diptera: Calliphoridae) nurse cells were similarly
hybridized in situ with the DNA library of the
Analysis of Sex Chromosome Homologies in Representatives
of the Family Calliphoridae
A. E. Vedernikov, T. V. Anan’ina, A. A. Kokhanenko, and V. N. Stegniy
Institute of Biology and Biophysics, Tomsk State University, Tomsk, 634050 Russia;
Received January 28, 2010
—The distribution of sequences homologous to the
Mg. sex chromosome
was studied in
sp. The chromatin structure was found to be similar
in regions containing homologous DNA sequences.
С. erythrocephala Lucilia
Nuclei of nurse cells in the ovaries of Calliphoridae: (a) a reticular nucleus and a nucleus with polytene chromosomes in
, (b) a
sp. reticular nucleus, and (c) a
nucleus with polytene chromosomes. The hybridiza
tion sites of the chromosomespecific DNA library of the
sex chromosome are indicated with arrows.