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1

Influence of replication on organization and evolution of bacterial genomes

100%
Kowalczuk M., Mackiewicz D., Mackiewicz P., Polak N., Cebrat S.
Biotechnologia
|
2005
|
issue 3
75-90
EN
In bacterial chromosomes, strong bias in nucleotide composition has been observed between differently replicated DNA strands (leading and lagging ones), and also in many species between the regions proximal and distal to the origin of replication (ori). This bias is also reflected in composition and distribution of genes along the chromosome. Several phenomena connected with the replication of the chromosome are responsible for such polarization, especially mutational pressure, repair mechanisms and recombinations, and also selection pressure. All these phenomena are not indifferent for gene evolution and their rearrangements which are strictly connected with the organization of bacterial chromosome.
2

Are all reports on diatoms older than cretaceous not credible ?

100%
Sieminska J.
Oceanological and Hydrobiological Studies
|
2003
|
issue 3
19-27
EN
A review of approximately 30 published reports on fossil diatoms older than Cretaceous is presented. Together with the Proterozoic diatom remnants found in Poland thirty years ago, the latest unquestionable finds of Cambrian diatoms (Vologdin 1962, Allison and Hilgest 1986, Gapeev 1992, 1995) and the recent report of the partial diatom provenance of siliceous grains in Late Devonian shales (Schieber et al. 2000) make these discoveries reliable.
3

Structure and evolution of plant disease resistance genes

100%
Lehman P.
Journal of Applied Genetics
|
2002
|
vol. 43
|
issue 4
403-414
EN
This article reviews recent advances that shed light on plant disease resistance genes, beginning with a brief overview of their structure, followed by their genomic organization and evolution. Plant disease resistance genes have been exhaustively investigated in terms of their structural organization, sequence evolution and genome distribution. There are probably hundreds of NBS-LRR sequences and other types of R-gene-like sequences within a typical plant genome. Recent studies revealed positive selection and selective maintenance of variation in plant resistance and defence-related genes. Plant resistance genes are highly polymorphic and have diverse recognition specificities. R-genes occur as members of clustered gene families that have evolved through duplication and diversification. These genes appear to evolve more rapidly than other regions of the genome, and domains such as the leucine-rich repeat, are subject to adaptive selection.
4

Chromosome evolution in the genus Poecilimon (Orthoptera, Tettigonioidea, Phanero- pteridae)

88%
Warchalowska-Sliwa E., Heller K. G., Maryanska-Nadachowska A., Lehmann A.
Folia Biologica
|
2000
|
vol. 48
|
issue 3-4
127-136
EN
Cytotaxonomic analysis of 20 species and subspecies of the genus Poecilimon using C-banding pattern, chiasma frequency, and morphometric characteristics of the chromosomes were described. Using a cladistic analysis the chromosome data provided a basis to produce a phylogenetic tree which was compared with a tree based on morphological characters and DNA sequence data. There are importent differences in the grouping of data sets to species obtained on the basis of morphology/DNA analyses and that based on chromosomes. The explanation of the differences between C-banding patterns and taxonomic proximity is probably that the C-banding pattern changes quickly as the result of the high degree of variation of constitutive heterochromatin.
5

Do germ-line cells in Allacma fusca (Insecta, Collembola, Symphypleona) have a higher metabolic rate than somatic cells

88%
Swiatek P., Klag J., Romek M.
Folia Biologica
|
2001
|
vol. 49
|
issue 1-2
85-90
EN
Stereological analysis of the ultrastructure of primordial germ cells (PGCs) and the somatic (ectoderm) cells in two developmental stages of embryos and freshly hatched juveniles of Allacma fusca have shown great differences in mitochondria volume density (vd) between the two types of cells. In younger embryos (migration phase of the PGCs) the vd of mitochondria in the cytoplasm of the PGCs is 74.64% higher than in the ectoderm cells. In older embryos, (PGCs in the gonads) the vd of mitochondria is 123% higher than the corresponding value for the somatic cells cytoplasm. In the juvenile the vd of mitochondria in the ectoderm cells grows twice but is still only 2/3 of the value for the PGCs. On the basis of papers describing a direct relationship between stereological and physiological results the authors conclude that the metabolism of the primordial germ cells during embryonic development of Allacma fusca is much higher than that of the somatic ones. If the above conclusion is correct, the results presented here confirm the ?disposable soma theory? (Kirkwood & Holliday 1979).
6

Molecular phylogenetics employing modern and ancient DNA

88%
Pusch C. M., Broghammer M., Blin N.
Journal of Applied Genetics
|
2003
|
vol. 44
|
issue 3
269-290
EN
Comparative studies of DNA in recent populations and characterisation of ancient hereditary material have contributed very interesting facts to our understanding of evolution of modern mankind. Analysis of DNA homology in related species, assessment of mutations and polymorphisms in various populations and new DNA sequence data from prehistoric finds allowed ? via sophisticated DNA extraction techniques, PCR, sequencing and digitalised processing of genetic information ? insights into possible roots of Homo sapiens and related species, migration patterns and ancient cultural habits, thus enriching the palaeoanthropological discipline. However, a presentation of this development would not be complete without pointing towards the methodological limitations and manifold presentations burdened with artifacts, data misinterpretation and unjustified conclusions. Presently, this modern field of research is in its consolidation phase and new parameters for quality control and authentication are being implemented to avoid spectacular but unfounded reports. It is expected that most of the problems connected to old biomolecules may be closely related to fossilisation parameters. The future challenge will be the full understanding of the complex and multi-faceted processes underlying diagenesis, including the elucidation of nucleic acid ?postmortem damage?.
7

Use of RAPD technique in evolution studies of four species in the family Canidae

88%
Stepniak E., Zagalska M. M., Switonski M.
Journal of Applied Genetics
|
2002
|
vol. 43
|
issue 4
489-499
EN
The RAPD-PCR technique was applied to identify genetic markers able to distinguish between four canid species: the arctic fox (Alopex lagopus), red fox (Vulpes vulpes), Chinese raccoon dog (Nyctereutes procyonoides procyonoides) and six breeds of the domestic dog (Canis familiaris). A total of 29 ten-nucleotide arbitrary primers were screened for their potential use in the differentiation of these species. Ten primers amplified RAPD profiles that made it possible to distinguish between the investigated taxa. A number of species-specific bands was scored within RAPD profiles produced by these primers: 35.6% of all the polymorphic bands were unique to the Chinese raccoon dog, 29.6% were unique to the domestic dog, 21.2% were diagnostic for the red fox and 13.6% for the arctic fox. No breed-specific fragments were amplified from canine DNA; however, three primers produced bands characteristic for the dog, but not present in all of the investigated breeds. A Neighbor-Joining tree constructed on the basis of the analysis of RAPD profiles amplified by six primers revealed that the phylogenetic distance between the dog and the arctic fox is larger than the distance between the dog and the red fox. The phylogenetic branch of the Chinese raccoon dog was the most distinct on the dendrogram, suggesting that this species belongs to a different phylogenetic lineage. Obtained results make it possible to conclude that RAPD analysis can be a powerful tool for developing molecular markers useful in distinguishing between species of the family Canidae and for studying their phylogenetic relations.
8

Molecular evolution of coding and non-coding sequences of the growth hormone receptor (GHR) gene in the family Bovidae

88%
Maj A., Zwierzchowski L.
Folia Biologica
|
2006
|
vol. 54
|
issue 1-2
31-36
EN
The GHR gene exon 1A and exon 4 with fragments of its flanking introns were sequenced in twelve Bovidae species and the obtained sequences were aligned and analysed by the ClustalW method. In coding exon 4 only three interspecies differences were found, one of which had an effect on the amino-acid sequence ? leucine 152 proline. The average mutation frequency in non-coding exon 1A was 10.5 per 100 bp, and was 4.6-fold higher than that in coding exon 4 (2.3 per 100 bp). The mutation frequency in intron sequences was similar to that in non-coding exon 1A (8.9 vs 10.5/100 bp). For non-coding exon 1A, the mutation levels were lower within than between the subfamilies Bovinae and Caprinae. Exon 4 was 100% identical within the genera Ovis, Capra, Bison, and Bos and 97.7% identical for Ovis moschatus, Ammotragus lervia and Bovinae species. The identity level of non-coding exon 1A of the GHR gene was 93.8% between species belonging to Bovinae and Caprinae. The average mutation rate was 0.2222/100 bp/MY and 0.0513/100 bp/MY for the Bovidae GHR gene exons 1A and 4, respectively. Thus, the GHR gene is well conserved in the Bovidae family. Also, in this study some novel intraspecies polymorphisms were found for cattle and sheep.
9

Karyotypes of the flatworms of the genus Geocentrophora (Turbellaria, Lecithoepitheliata) from Lake Baikal

88%
Novikova O. A.
Folia Biologica
|
1999
|
vol. 47
|
issue 1-2
13-19
EN
Karyotypes of turbellaria of the genus Geocentrophora (Lecithoepitheliata: Prorhynchidae) from Lake Baikal (Russia): G. wagini (2n=26, NF=36), G. porfirievae, (2n=30, NF=58), G. levanidorum (2n=28, NF=54), G. intersticialis (2n=30, NF=42) and G. incognita (2n=26) are reported for the first time.
10

Cytogenetic characterization of the trinidad endemic, Arachnocoris trinitatus Bergroth: the first data for the tribe arachnocorini (Heteroptera: Cimicomorpha: Nabidae)

63%
Kuznetsova V. G., Grozeva S., Sewlal J. N., Nokkala S.
|
2007
|
vol. 55
|
issue 1-2
17-26
EN
Cimicomorpha), the first evidence for the tribe Arachnocorini (the subfamily Nabinae), with reference to the Trinidad endemic, Arachnocoris trinitatus Bergroth, is provided. This is an attempt to gain a better insight into the evolution, systematics and within-family relationships of the family Nabidae. The studies were conducted using a number of cytogenetic techniques. The male karyotype (chromosome number and size; sex chromosome system; NOR location; C-heterochromatin amount, distribution and characterization in terms of the presence of AT-rich and GC-rich DNA), and male meiosis with particular emphasis on the behavior of the sex chromosomes in metaphase II are described. Also investigated are the male and female internal reproductive organs with special reference to the number of follicles in a testis and the number of ovarioles in an ovary. A. trinitatus was found to display a number of characters differentiating it from all hitherto studied nabid species placed in the tribe Nabini of the subfamily Nabinae, and in the tribe Prostemmatini of the subfamily Prostemmatinae. Among these characters are chromosome number 2n = 12 (10 + XY), the lowest within the family, nucleolus organizer regions (NORs) situated on the autosomes rather than on the sex chromosomes as is the case in other nabid species, and testes composed of 3 follicles but not of 7 as in other nabids. All the data obtained suggest many transformations during the evolution of A. trinitatus.
11

Some aspects of karyotype of Liarina (Orthoptera: Tettigoniidae, Agraeciini) from Vietnam

63%
Warchalowska-Sliwa E., Gorochov A. V., Gorochov A. V.
Folia Biologica
|
2000
|
vol. 48
|
issue 3-4
119-125
EN
Karyotypes (chromosome number and shape) of four species of the subtribe Liarina were studied. The chromosome numbers and NF (Fundamental Number) in this group of species range from 2n%=33 (34) to 27(30): Liaromorpha buonluoiensis 2n%=33 (34), Sialaiana transiens 2n%=29 (34), Liara tramlapensis 2n%=29 (32), and Anelytra (Perianelytra) propria 2n%=27 (30). Cyto-taxonomy analysis indicates an intensive karyotype evolution among species belonging to three different groups of the genera. Differences of karyotypes are connected with Robertsonian fusion and tandem fusion in autosomes. Additionally, C-banding distribution and location of the NORs were studied.
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