[C-heterochromatin during synapsis and recombination in grey cockroach Nauphoeta cinerea spermatogenesis].

The behaviour of large distal C-heterochromatic blocks in spermatogenesis of grey cockroach Nauphoeta cinerea was investigated by light and electron microscopy. Heterochromatic blocks of some autosomes are involved into nonhomologous association with formation of chromocenter in early meiotic prophase I. Fluorescent in situ hybridization with ribosomal DNA-probe revealed the signal on only two pairs of middle chromosomes, which did not participate in the chromocenter formation, therefore appearance of ectopic contacts was not caused by the nucleolus formation.

[Chromosome nondisjunction in Drosophila strains mutant for tumor suppressor Merlin].

The effect of mutation for gene Merlin on chromosome disjunction in Drosophila during meiosis was genetically studied. Chromosome nondisjunction was not registered in females heterozygous for this mutation and containing structurally normal X chromosomes. In cases when these females additionally contained inversion in one of chromosomes X, a tendency toward the appearance of nondisjunction events was observed in individuals containing mutation in the heterozygote.

[Range of potential functions of the Drosophila melanogaster hdc gene].

The Drosophila melanogaster hdc gene controls trachea branching, which starts during embryo development. Expression in imaginal disks and reproductive organs suggests additional functions for the hdc gene. The gene was demonstrated to have a maternal effect, which was denied previously.

[Reconstruction of phylogeny of locusts from the family Acrididae (Orthoptera) based on analysis of nucleotide sequences of 16S ribosome RNA gene in mitochondria].

The sequences of two mitochondrial 16S RNA gene fragments (137- and 174-bp in size) were determined in nine grasshopper species belonging to three Acrididae subfamilies. Phylogenetic reconstruction was performed using the sequences of twelve grasshopper species and the cricket Acheta domesticus sequence as an outgroup (some data were purchased from the GeneBank Data Library (NCBI). In the phylogenetic tree, the Acridinae and Locustinae formed compact groups.

[Cytogenetic analysis of recombination interactions].

Chiasma interference between separate regions of chromosomes was studied in three phylogenetically distant species. All these species displayed the similar patterns of chiasma interference. Chiasma completely suppressed recombination in the regions next to chiasma within a chromosome's arm.