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31.
Genomes of higher eukaryotes are mosaics of segments with various structural, functional, and evolutionary properties. The availability of whole-genome sequences allows the investigation of their structure as "texts" using different statistical and computational methods. One such method, referred to as Compositional Spectra (CS) analysis, is based on scoring the occurrences of fixed-length oligonucleotides (k-mers) in the target DNA sequence. CS analysis allows generating species- or region-specific characteristics of the genome, regardless of their length and the presence of coding DNA. In this study, we consider the heterogeneity of vertebrate genomes as a joint effect of regional variation in sequence organization superimposed on the differences in nucleotide composition. We estimated compositional and organizational heterogeneity of genome and chromosome sequences separately and found that both heterogeneity types vary widely among genomes as well as among chromosomes in all investigated taxonomic groups. The high correspondence of heterogeneity scores obtained on three genome fractions, coding, repetitive, and the remaining part of the noncoding DNA (the genome dark matter--GDM) allows the assumption that CS-heterogeneity may have functional relevance to genome regulation. Of special interest for such interpretation is the fact that natural GDM sequences display the highest deviation from the corresponding reshuffled sequences. 相似文献
32.
In some phytoremediation studies it is desirable to separate and define the specific contribution of plants and root-colonizing bacteria towards contaminant removal. Separating the influence of plants and associated bacteria is a difficult task for soil root environments. Growing plants hydroponically provides more control over the biological factors in contaminant removal. In this study, a hydroponic system was designed to evaluate the role of sterile plant roots, rhizodeposition, and root-associated bacteria in the removal of a model contaminant, phenol. A strain of Pseudomonas pseudoalcaligenes that grows on phenol was inoculated onto plant roots. The introduced biofilm persisted in the root zone and promoted phenol removal over non-augmented controls. These findings indicate that this hydroponic system can be a valuable tool for phytoremediation studies that investigate the effects of biotic and abiotic factors on pollution remediation. 相似文献
33.
An approach to increase the resolution power of interval mapping of quantitative trait (QT) loci is proposed, based on analysis of correlated trait complexes. For a given set of QTs, the broad sense heritability attributed to a QT locus (QTL) (say, A/ a) is an increasing function of the number of traits. Thus, for some traits x and y, H(xy)(2) (A/ a) >/= H(x)(2) (A/ a). The last inequality holds even if y does not depend on A/ a at all, but x and y are correlated within the groups AA, Aa and aa due to nongenetic factors and segregation of genes from other chromosomes. A simple relationship connects H(2) (both in single trait and two-trait analysis) with the expected LOD value, ELOD = -1/2N log(1 - H(2)). Thus, situations could exist that from the inequality H(xy)(2) (A/ a) >/= H(x)(2) (A/ a) a higher resolution is provided by the two-trait analysis as compared to the single-trait analysis, in spite of the increased number of parameters. Employing LOD-score procedure to simulated backcross data, we showed that the resolution power of the QTL mapping model can be elevated if correlation between QTs is taken into account. The method allows us to test numerous biologically important hypotheses concerning manifold effects of genomic segments on the defined trait complex (means, variances and correlations). 相似文献
34.
Shashank M Patil KR Maruthi Shrisha Naik Bajpe VM Vyshali S Sushmitha Chagalamari Akhila Ramith Ramu 《Bioinformation》2021,17(11):932
Treatment of SARS-CoV-2 targeting its RNA dependent RNA polymerase (RdRp) is of current interest. Remdesivir has been approved for the treatment of COVID-19 around the world. However, the drug has been linked with pharmacological limitations like adverse effects and reduced efficiency. Nevertheless, recent advancements have depicted molnupiravir as an effective therapeutic agent to target the SARS-CoV-2 RdRp. The drug has cleared both in vitro and in vivo screening. It is in phase-III clinical trial. Nonetheless, there are no data on themolecular binding interaction of molnupiravir with RdRp. Therefore, it is of interest to report the binding interaction of molnupiravir using molecular docking. It is also of interest to show its stability during interaction using molecular dynamics and binding free energy calculations along with drug likeliness and pharmacokinetic properties in comparison with remdesivir. 相似文献
35.
This paper deals with the problem of polymorphism maintenance in species coevolution mediated by selection for quantitative traits controlled by Mendelian genes. We showed here that the conditions for polymorphism maintenance in interacting species can be deduced from the behavior of the isolated partners in stable and changing environments. This allows also to address such difficult questions as evolution of sex and recombination, that can not be considered properly in non-Mendelian models. An abundance of polymorphic regimes was revealed in the proposed genetic model. The obtained results demonstrate a remarkable property of trait-dependent coevolution concerning the conditions for maintenance of genetic polymorphism: what seems to be more realistic, that is, non-equal gene effects and deviation from purely additive within-locus gene action, promotes polymorphism. 相似文献
36.
37.
Rute ST Martins Laurence AM Deloffre Constantinos C Mylonas Deborah M Power Adelino VM Canário 《Reproductive biology and endocrinology : RB&E》2007,5(1):19
Background
DAX1 (NR0B1), a member of the nuclear receptors super family, has been shown to be involved in the genetic sex determination and in gonadal differentiation in several vertebrate species. In the aquaculture fish European sea bass, Dicentrarchus labrax, and in the generality of fish species, the mechanisms of sex determination and differentiation have not been elucidated. The present study aimed at characterizing the European DAX1 gene and its developmental expression at the mRNA level. 相似文献38.
Redouan Bshary Rui F Oliveira Tânia SF Oliveira Adelino VM Canário 《Frontiers in zoology》2007,4(1):1-8
Background
Marine cleaning interactions in which cleaner fish or shrimps remove parasites from visiting 'client' reef fish are a textbook example of mutualism. However, there is yet no conclusive evidence that cleaning organisms significantly improve the health of their clients. We tested the stress response of wild caught individuals of two client species, Chromis dimidiata and Pseudanthias squamipinnis, that had either access to a cleaner wrasse Labroides dimidiatus, or to cleaner shrimps Stenopus hispidus and Periclimenes longicarpus, or no access to cleaning organisms.Results
For both client species, we found an association between the presence of cleaner organisms and a reduction in the short term stress response of client fish to capture, transport and one hour confinement in small aquaria, as measured with cortisol levels.Conclusion
It is conceivable that individuals who are more easily stressed than others pay a fitness cost in the long run. Thus, our data suggest that marine cleaning mutualisms are indeed mutualistic. More generally, measures of stress responses or basal levels may provide a useful tool to assess the impact of interspecific interactions on the partner species. 相似文献39.
Edaphic microsatellite DNA divergence in wild emmer wheat, Triticum dicoccoides, at a microsite: Tabigha, Israel 总被引:1,自引:0,他引:1
Y. C. Li T. Fahima J. H. Peng M.S. Röder V. M. Kirzhner A. Beiles A. B. Korol E. Nevo 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2000,101(7):1029-1038
Twenty eight microsatellite markers were used to analyze genetic divergence in tandem dinucleotide repeated DNA regions between
two edaphic subpopulations of Triticum dicoccoides growing on the contrasting terra rossa and basalt soilsfrom a microsite at Tabigha, north of the Sea of Galilee, Israel. The
terra rossa soil niche was drier and more stressful than the basalt throughout the growing season (November to May). Significant
microsatellite divergence in allele distribution, repeat length, genetic diversity, and linkage disequilibria were found between
emmer wheat from the two soil types over two short transects of 100 m each. Soil-specific and -unique alleles and linkage disequilibria were observed in the terra rossa and basalt subpopulations. A permutation test showed that
the effects of random genetic drift were very low for the significant genetic diversity at microsatellite loci between the
two subpopulations, suggesting that an adaptive molecular pattern derived by edaphic selection may act upon variation of the
microsatellites.
Received: 4 February 2000 / Accepted: 31 March 2000<@head-com-p1a.lf>Communicated by H.F. Linskens 相似文献