Approaches to the analysis of reciprocal chromosome distribution in the bone marrow cells of mice

A study was made of G-banding chromosome preparations made of bone marrow cells of BALB/c mouse females, injected intraperitoneally with a single dose of the antibiotic adriamycin 23 hours before sacrifice. Frequencies of different chromosome fusions in pericentromeric regions were analysed. All chromosomes were found to be involved in the interchromosomal associations, different chromosomes participating in such fusions with different frequency. No associations of homologous chromosomes were observed. For each chromosome a limited number of preferential partners for fusion was revealed, the number of such partners for different chromosomes varying. Almost for a half of chromosomes, chromosome 15 was one of the most preferred partners. Possible significance of the data obtained is discussed for the analysis of principles of the spatial chromosome arrangement in murine bone marrow cells.     

Genetic control of the substrate specificity of sheep plasma arylesterase]

By means of starch gel electrophoresis blood plasma esterases in sheep of different breeds were studied. It is shown that the esterase pattern is a poly-enzyme system consisting of at least three enzymes: arylesterase, carboxylesterase and choline esterase. Postnatal changes of esterase pattern in sheep blood plasma were also studied. Polymorphism on substrate specificities is described, which is expressed in the fact that different arylesterase variants have different affinity to alpha- and beta-isomers of carbone ethers of naphtol. The breeding test suggests that two allelic autosomal genes, reffered to as Es-1a and Es-1b, control the substrate specificity of arylesterase in sheep. The data are discussed in connection with Es-1a and Es-1b gene expression in heterozygous sheep, with the effect of (mosaic) dominance.     

Evolutionary history of bacteriophages with double-stranded DNA genomes

Background

Reconstruction of evolutionary history of bacteriophages is a difficult problem because of fast sequence drift and lack of omnipresent genes in phage genomes. Moreover, losses and recombinational exchanges of genes are so pervasive in phages that the plausibility of phylogenetic inference in phage kingdom has been questioned.

Results

We compiled the profiles of presence and absence of 803 orthologous genes in 158 completely sequenced phages with double-stranded DNA genomes and used these gene content vectors to infer the evolutionary history of phages. There were 18 well-supported clades, mostly corresponding to accepted genera, but in some cases appearing to define new taxonomic groups. Conflicts between this phylogeny and trees constructed from sequence alignments of phage proteins were exploited to infer 294 specific acts of intergenome gene transfer.

Conclusion

A notoriously reticulate evolutionary history of fast-evolving phages can be reconstructed in considerable detail by quantitative comparative genomics.

Open peer review

This article was reviewed by Eugene Koonin, Nicholas Galtier and Martijn Huynen.     

The genetic structure of Kulunda sheep]

The analysis of the genetic structure of the Kulunda sheep in eight polymorphous genetic-biochemical systems was carried out. While comparing with the genetic structures of number of sheep breeds, differentiated by the origin history, productivity traits and the breeding regions, the locus-specificity particularities of the Kulunda sheep were described. The importance of creating of the "genetic portrait" for disappearing breeds was discussed.     

Genetic structure of local Ukrainian cattle breeds

Analysis of 6 cattle breeds (5 local Ukrainian breeds and the Holstain breed) on the 9 polymorphous molecular-genetic markers (transferrin, ceruloplasmin, amylase-1, posttransferrin, receptor to vitamin D, haemoglobin, leptin, kapa-casein) was carried out. The rare allele of transferrin was revealed in two local breeds and the rare allele of leptin--in two another local breeds. Associations between syntenic loci (transferrin, ceruloplasmin, kappa-casein, receptor to vitamin D) were observed only in the local breeds but not in the Holstain one. Locus-specific conservation of the ancestor allelic variants in the local breeds and effect of selection on interloci associations are discussed.     

Origin of a substantial fraction of human regulatory sequences from transposable elements

Transposable elements (TEs) are abundant in mammalian genomes and have potentially contributed to their hosts' evolution by providing novel regulatory or coding sequences. We surveyed different classes of regulatory region in the human genome to assess systematically the potential contribution of TEs to gene regulation. Almost 25% of the analyzed promoter regions contain TE-derived sequences, including many experimentally characterized cis-regulatory elements. Scaffold/matrix attachment regions (S/MARs) and locus control regions (LCRs) that are involved in the simultaneous regulation of multiple genes also contain numerous TE-derived sequences. Thus, TEs have probably contributed substantially to the evolution of both gene-specific and global patterns of human gene regulation.     

Geographic and breed distribution of an Msp I PCR-RFLP in the bovine growth hormone (bGH) gene

Information is presented on the frequency of the Msp I (-) allele in the third intron of the bovine growth hormone gene in a large number of cattle breeds. Consideration of the breed frequencies in relation to their geographic origin shows a low frequency for breeds originating in Northern Europe, moderate frequencies for breeds originating in Eastern Europe or the countries surrounding the Mediterranean basin, and very high frequencies for breeds originating in the Indian subcontinent. Consideration of breed frequencies in relation to breed type, shows low to moderate frequencies for the humpless breeds, high frequencies for the humped breeds. Various explanations for this distribution are discussed, among them the possibility that the Msp I (-) allele originated in the Bos indicus breeds of the Indian subcontinent, from which it diffused through the humpless Bos taurus breeds of Eastern Europe, the Mediterranean basin, eventually reaching Western, Northern Europe, Western Africa in low frequencies.     

Genetically determined enzyme polymorphism in soy varieties (Glycine max) and in wild soy (Glycine soja)

Analysis of 22 genetic-biochemical systems (42 loci) in 18 varieties of domestic soybean (G. max) and in 3 population of wild soybean (G. soja) was carried out. The part of polymorphous loci (P), intraspecies genetic differentiation (genetic distances--DN) were higher in domestic plants in comparison with wild ones (P = 45%, 17%: DN = 0.038-0.269, 0.059-0129). The preferable polymorphism of loci, coding the enzymes of glycolysis and Kreb's cycle was revealed in wild species. Domestic soybean had more polymorphous enzyme loci, which did not participate in glucose metabolism in comparison with wild species. The presence of the specific part of the gene pool in ancestor species, which was involved in soybean domestication and forming of varieties was discussed.     

Participation of structural gene markers and anonymous DNA sequences in genetic differentiation in the species Ovis aries L. and Ovis nivicola borealis

Genetic variability and genetic differentiation in two Ovis species--domesticated (Askanian sheep, Sokilska and Kulunda sheep) and wild (bighorn sheep) were analyzed using different types of molecular-genetic markers--genetic-biochemical (30 loci) and DNA (ISSR-PCR) ones. High level of genetic variability was revealed. The average heterozygosity of biochemical markers loci was in range of 0.073-0.188. Markers involved into process of genofond divergence of two closely related species were revealed.