GENES CODING RIBOSOMAL PROTEIN RPL11 AND 5,8S RIBOSOMAL RNA IN SPECIES OF GENUS CHIRONOMUS: NUCLEOTIDE VARIABILITY, DIVERGENCE AND CHROMOSOMAL LOCATION.

Ribosomes of eukaryotic cells contain four rRNA’s (28S, 18S, 5,8S and 5S) and about 80 ribosomal proteins (RP). Whereas the patterns of evolution and chromosomal location of rRNA genes are studied rather extensively in many taxonomic groups, there is only scarce information about evolution of genes coding ribosomal proteins. To obtain more information about evolution of ribosomal protein genes, the study of the nucleotide sequences and chromosomal location of rp111 gene was carried out in 12 species of the genus Chironomus.

Chromosomal organization of the ribosomal RNA genes in the genus Chironomus (Diptera, Chironomidae).

Chromosomal localization of ribosomal RNA coding genes has been studied by using FISH (fluorescence in situ hybridization) in 21 species from the genus Chironomus Meigen, 1803. Analysis of the data has shown intra- and interspecific variation in number and location of 5.8S rDNA hybridization sites in 17 species from the subgenus Chironomus and 4 species from the subgenus Camptochironomus Kieffer, 1914.

[Differentiation of chromosome banding sequence pools and genomic DNA in holarctic natural populations of Chironomus entis Shobanov (Diptera, Chironomidae)].

Polymorphism and differentiation of the chromosome banding sequence pools and genomic DNA were studied in three natural populations of Chironomus entis from Europe and North America. These populations showed a moderate level of chromosome polymorphism and high RAPD polymorphism of genomic DNA. The Palearctic and Nearctic populations of this species did not differ significantly in the levels of chromosome and genomic DNA polymorphism.

[Chromosomal variability in natural populations of Chironomus cingulatus Meigen (Diptera, Chironomidae)].

Chromosomal polymorphism has been investigated in 7 natural populations from West Europe, West Siberia and Sakha Republic (Yakutia). The pool of polytene chromosome banding sequences of this species includes 15 banding sequences. The chromosomal polymorphism has been revealed in 5 of chromosomal arms.

[Geographic differentiation of genomic DNA of Chironomus plumosus (Diptera, Chironomidae) in natural holarctic populations].

Using RAPD markers, polymorphism and differentiation of genomic DNA was examined in seven natural populations of Chironomus plumosus from Europe, Siberia, and North America. All these populations showed high polymorphism of genomic DNA. The Palearctic and Nearctic populations of this species were not statistically significantly different in the genomic DNA polymorphism level.

[The geographic varyability of the polytene chromosome banding sequence of non-biting midje Chironomus pseudothummi str. (Diptera, Chironomidae)].

The karyotypes and chromosomal polymorphism of Chironomus pseudothummi were investigated in different parts of its range. It was established that chromosomal variability in the natural populations of this species was represented mainly by the inversion polymorphism of arm G. Only rare and unique inversions were found as heterozygous in arms C, D, and E.

[Polymorphism and differentiation of multilocus DNA markers in natural populations of Drosophila melanogaster].

Using multilocus (RAPD) markers, variation and divergence of genomic DNA was examined in two Drosophila melanogaster populations from Russia and three populations from Ukraine. The populations were found to exhibit high polymorphism at RAPD markers. Estimation of genetic distances between the populations showed low differentiation of geographically distant populations of D.

[Variation and divergence of multilocus genome markers in the species of the genus Chironomus (Diptera, Chironomidae)].

Variation and divergence patterns of the multilocus genome markers in twelve Chironomus species belonging to the plumosus and piger sibling-species groups were examined by use of polymerase chain reaction with random primers (RAPD method). The chironomid species showed high levels of the RAPD markers polymorphism. The genetic distances (GD) were determined between the species within the group of closely related species, as well as between the species from different groups.

[Divergence patterns of banding sequences in different polytene chromosome arms reflect relatively independent evolution of different genome components].

Divergence patterns of the banding sequences from the chromosomal arms A, C, D, E, and F were compared in 63 species of the genus Chironomus. Evaluation of the number of breakpoints between the pairs of inverted banding sequences and the analysis of the lengths of the conserved segments in the chromosomal arms in the chironomid species examined showed that different arms evolved relatively independently and at different rates. No direct correlation between the arm length and the breakpoints number was observed.

[Divergence of the polytene chromosome banding sequences as a reflection of evolutionary rearrangements of the genome linear structure].

Banding sequences of five chromosomal arms (A, C, D, E, and F), accounting for about 70% of the total genome size in 63 Chironomus species, were used as phylogenetic markers to analyze divergence patterns of the linear genome structure during the evolution. The number of chromosomal breakpoints between the pairs of banding sequences compared served as a measure of divergence. It was demonstrated that the greater the divergence between the species compared, the higher the number of chromosomal breakpoints and the smaller the size of the conserved chromosomal regions.

[Polymorphism and divergence of multilocus DNA markers in sibling species Chironomus riparius Meigen and Chironomus piger Strenzke (Diptera, Chironomidae)].

Intra- and interspecific variation and divergence of multilocus markers for genomic DNA of the sibling species from the thimmi group, Chironomus riparius and C. piger, were studied by PCR with arbitrary primers (RAPD). A high level of RAPD polymorphism was determined in both laboratory and natural populations of these species.

[DNA polymorphism of Drosophila genes and factors determining it].

The data on variation of DNA sequences in genes of Drosophilidae are reviewed. Intraspecific polymorphism and interspecific divergence of DNA nucleotide sequences are shown to be characteristic of most genes. The level of intraspecific polymorphism and interspecific DNA divergence and the degree of correlation between them depend on the mode, intensity, and direction of natural selection, as well as on the evolutionary history of the genes and species.

[Divergence of karyofunds in sibling species of the plumosus group (Diptera: Chironomidae)].

Cytogenetic differentiation of eight sibling species of the plumosus group was examined. The karyofunds of these sibling species were shown to diverge incompletely. In each species karyofund, the banding sequences homologous to those of the remaining species of this group were revealed.

[Possibilities of synchronizing the growth of Chironomus thummi Kieff. larvae].

The conditions for uniform synchronous development of groups of the IV instar larvae of Ch. thummi and the possibility of using the morphology of imaginal discs as a criterion of temporal uniformity (synchrony) of larval development were investigated. The degree of synchrony of larval development was shown to depend strongly on the population density.

[Dynamics of 3H-thymidine and 3H-deoxycytidine incorporation into the nuclei of a rabbit kidney cell culture during the S period].

Using a combined cytophotometric-autoradiographic method a study was made of 3H-thymidine and 3H-deoxycytidine incorporation rates into the interphase nuclei of rabbit kidney cell culture during the S-period. The rate of 3H-deoxycytidine (10(-4) M--10(-6) M) incorporation into nuclei increases throughout the first part of the S-period and decreases from its middle to the end. The patterns of variations of 3H-thymidine and 3H-deoxycytidine incorporation rates into the nuclei of cultured rabbit kidney cells during the S-period were identical.