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2.
Svetlana A. Semerikova Vladimir L. Semerikov Martin Lascoux 《Journal of Biogeography》2011,38(2):326-340
Aim The main aim of the present study is to infer the post‐glacial history of Abies species from north‐east Asia and to test the hypotheses that coastal Abies populations suffered less from climatic fluctuations during Pleistocene glacial periods than their more continental counterparts, and that Sakhalin was a major area of introgression. Location Natural ranges of the fir species Abies nephrolepis, Abies sachalinensis and Abies holophylla in the Russian Far East, and of Abies gracilis, which is endemic to the Kamchatka Peninsula. Methods Nineteen populations were sampled for allozyme analysis. Seventeen of these populations were also screened for variation at two paternally inherited chloroplast DNA microsatellite loci (cpSSR) and variation at one maternally inherited mitochondrial marker (nad4‐3/4). Finally a subset of 11 populations was analysed with amplified fragment length polymorphism (AFLP). Comparisons were made with already available Abies sibirica data. For all sets of markers, we estimated genetic diversity and differentiation using an analysis of molecular variance (AMOVA). Population clustering was assessed with a Bayesian approach implemented in structure v.2.3. Results Among the three major species, A. sibirica, A. nephrolepis and A. sachalinensis, A. sachalinensis demonstrated the highest cytoplasmic and nuclear diversity and the most continental species, A. sibirica, the lowest. Both nuclear and mitochondrial DNA markers revealed the presence of a transitional zone on Sakhalin Island between A. nephrolepis and A. sachalinensis of south Sakhalin. The structure analysis delivered very clear results confirming the admixed origin of A. sachalinensis, with a genetic contribution from A. nephrolepis. No variation in cytoplasmic markers was found in A. gracilis, suggesting the occurrence of a recent bottleneck. Main conclusions There is a clear reduction of genetic diversity in Abies species from the Pacific coast into the continent. The higher diversity in A. sachalinensis could have two causes: a larger effective population size in the islands due to relatively stable climatic conditions and consequently less pronounced demographic fluctuations in population size and/or hybridization with continental and Japanese populations. Sakhalin Island is a major transitional zone for conifer species. Finally, the fir from Kamchatka, A. gracilis, should be regarded as a separate species closely related to the A. nephrolepis–A. sachalinensis complex. 相似文献
3.
Announcement
1988 Gordon Conference on Theoretical Biology and Biomathematics Tilton Academy, Tilton, New Hampshire, U.S.A., 13–17 June 1988 相似文献4.
Svetlana D. Pack Vladimir M. Bedanov Olga V. Sokolova Natalia S. Zhdanova Natalia M. Matveeva Oleg L. Serov 《Mammalian genome》1992,3(2):112-118
To expand the mink map, we established a new panel consisting of 23 mink-mouse clones. On the basis of statistical criteria (Wijnen et al. 1977; Burgerhout 1978), we developed a computer program for choice of clones of the panel. Assignments of the following mink genes were achieved with the use of the hybrid panel: glyoxalase (GLO), Chromosome (Chr) 1; acetyl acylase (ACY), Chr 5; creatine phosphokinase B (CKBB), Chr 10; alcohol dehydrogenase-2 (subunit B) (ADH2), Chr 8. Using a series of clones carrying rearrangements involving mink Chr 1 and 8, we assigned the gene for ME1 to the short arm of Chr 1 and that for ADH2 to Chr 8, in the region 8p12-p24. Mapping results confirm the ones we previously obtained with a mink-Chinese hamster panel. However, by means of an improved electrophoretic technique, we revised the localization of the gene for purine nucleoside phosphorylase (NP), which has been thought to be on mink Chr 2. It is reassigned to mink Chr 10. 相似文献
5.
When amino acids are added to the culture of Bacillus polymyxa growing under the conditions of active spore formation, the rate of polymyxin biosynthesis and the quantity of spores being formed decrease. All cells in the population start to produce spores under these conditions, but only some of them pass through all of the differentiation stages. Most of the cells remain in the state of prospores. Some cells which have started to differentiate are characterized by ultrastructural anomalies, do not form prospores and undergo early lysis. 相似文献
6.
Experiments have been carried out on Chinese hamster fibroblasts. Cultures at the log-stage of growth were incubated at 15 or 25° C for 24 hrs. In two groups of experiments the cells were labeled with H3-TdR for 6 hrs at the respective temperature, washed and further incubated at 37° C. In each group of experiments cultures labeled with H3-TdR at 37° C for 20 min were used as a control. It was found: 1. the delay in the onset of cell passage through the mitotic cycle at 37° in cultures exposed to 15 or 25° C was about equal to 1,5-1 hr resp. and cells proceeded through the life cycle without blockages at any phase of the cycle; 2. the patterns of chromosome reproduction during the second half of the S-phase were the same after labeling at 15, 25 and 37° C. — In the third group the cells were labelled with HP-TdR for 10–60 min and 6 hrs resp. at 25° C. The patterns of reproduction of chromosome pairs 1–4 and small metacentrics were found to be the same in cells labeled briefly and those labeled for 6 hrs. After brief labeling asynchronous reduplication of different segments in many chromosomes became evident. It was masked because of heavy labeling after 6 hrs treatment. 相似文献
7.
Phasmids as effective and simple tools for construction and analysis of gene libraries 总被引:1,自引:0,他引:1
N K Yankovsky N O Fonstein MYuLashina SYu Bukanov N V Yakubovich L M Ermakova B A Rebentish A A Janulaitis V G Debabov 《Gene》1989,81(2):203-210
Phasmid lambda pMYF131, a hybrid of phage lambda vectors and plasmid pUC19, was constructed. The phasmid and its derivatives were shown to be efficient vectors for construction and analysis of gene libraries in Escherichia coli cells. The lambda pMYF131 DNA molecule contains all the genes and regions essential for phage lytic development. The plasmid cannot be packaged either in the monomeric or the oligomeric form due to its specific length. Elongation of the DNA molecule by ligation with fragments of foreign DNA can make it packageable and this is easily detected by plaque formation. Hence, the procedures used to construct genomic libraries can be simplified by selection of only recombinant DNA molecules just at the time and on the basis of their packaging in vitro. The output of recombinant clones per vector molecule was several times higher for vector lambda pMYF131, compared to phage vector lambda L47.1AB, and attained 3 x 10(6) clones per micrograms DNA. Vector and recombinant phasmids can be obtained in large quantities in plasmid form. lambda pMYF131 contains nine unique restriction sites which allow the cloning of DNA fragments with blunt ends and of fragments with various types of cohesive ends, obtained by digestion with 14 prototype restriction enzymes. The maximal size of the cloned DNA fragments is approx. 20 kb for lambda pMYF131. Phasmid vectors were used to construct libraries of bovine, pig and quail genomes, and genomic libraries of 17 species of bacteria. Application of suitable methods allowed the identification 13 individual genes within these libraries. 相似文献
8.
The application of molecular tools to questions related to the genetics, ecology and evolution of actinorhizal symbiotic systems has been especially fruitful during the past two years. Host plant phylogenies based on molecular data have revealed markedly different relationships among host plants than have previously been suspected and have contributed to the development of new hypotheses on the origin and evolution of actinorhizal symbiotic systems. Molecular analyses of host plant gene expression in developing nodules have confirmed the occurrence of nodulin proteins and in situ hybridization techniques have been successfully adapted to permit the study of the spatial and temporal patterns of gene expression within actinorhizal nodules. The use of heterologous probes in combination with nucleotide sequence analysis have allowed a number of nif genes to be mapped on the Frankia chromosome which will ultimately contribute to the development of hypotheses related to nif gene regulation in Frankia. The use of both 16S and 23S rDNA nucleotide sequences has allowed the construction of phylogenetic trees that can be tested for congruence with symbiotic characters. In addition the development of Frankia-specific gene probes and amplification primers have contributed to studies on the genetic diversity and distribution of Frankia in the soil. 相似文献
9.
Glutaredoxin is a small protein (12 kDa) catalyzing glutathione-dependent disulfide oxidoreduction reactions in a coupled system with NADPH, GSH, and glutathione reductase. A cDNA encoding the human glutaredoxin gene (HGMW-approved symbol GLRX) has recently been isolated and cloned from a human fetal spleen cDNA library. The screening of a human genomic library in Charon 4A led to the identification of three genomic clones. Using fluorescencein situhybridization to metaphase chromosomes with one genomic clone as a probe, the human glutaredoxin gene was localized to chromosomal region 5q14. This localization at chromosome 5 was in agreement with the somatic cell hybrid analysis, using DNA from a human–hamster and a human–mouse hybrid panel and using a human glutaredoxin cDNA as a probe. 相似文献
10.
Valery Kukharenko Svetlana Sheleg Mikhail Freudine Elena Pichugina Alexander Delvig 《Human genetics》1994,94(1):80-82
Synthesis of glycosaminoglycans (GAGS) by fibroblasts derived from seven patients with Down's syndrome, five patients with Edwards' syndrome, and two patients with Patau's syndrome were studied in cell culture. The aneuploid strains were compared with diploid fibroblasts from age-matched controls. In terms of hyaluronic acid and sulfated GAG synthesis, the amount of synthesized hyaluronic acid was not significantly different between postnatal aneuploid strains and controls. 相似文献