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1.
J. H. Roberds G. Namkoong T. Skrøppa 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1990,79(6):841-848
Summary A major concern arising from the culture of clonally propagated crops of forest trees is risk of catastrophic loss due to an agent or event not anticipated at the time of population establishment. Since danger of such a catastrophe depends to some degree on the genetic variability within clonal mixtures, attention has been focused on the number of clones needed to keep the risk of catastrophic loss below specified levels. In this paper, we describe a genetical analysis of susceptibility to a destructive agent and the effect that frequency of genes for susceptibility have on the number of clones needed to effectively manage this risk. As a part of the analysis, parameters representing the minimum unacceptable mortality rates in plantations () and acceptable levels of risk () are defined, and their effects on the number of single-pair matings needed for the production of clonal stock are evaluated. Dominance and recessive gene action models for a single two-allele genetic locus are investigated. Probabilities for plantation failure are functions of the gene frequency for the allele conferring susceptibility. These functions converge to zero for allele frequencies less than but to one for frequencies greater than or equal to . This convergence is periodic rather than monotonie, since probabilities for plantation failure increase rather than decrease over restricted ranges of increasing numbers of clones. Recessive and dominance gene actions are found to have different effects on the minimum number of clones needed to attain acceptable risk levels. For conditions in which substantial numbers of clones are required, selecting multiple clones per mating is an effective method for reducing the number of matings necessary to achieve acceptable risks.Paper No. 12480 of the Journal Series of the North Carolina Agriculture Research Service, Raleigh, NC 27695-7643, USA 相似文献
2.
Rainer Klocke Steven L. Roberds Michael M. Tamkun Monika Gronemeier Andr Augustin Barbara Albrecht Olaf Pongs Harald Jockusch 《Genomics》1993,18(3)
The four Shaker-like subfamilies of Shaker-, Shab-,Shaw-, and Shal-related K+ channels in mammals have been defined on the basis of their sequence homologies to the corresponding Drosophila genes. Using interspecific backcrosses between Mus musculus and Mus spretus, we have chromosomally mapped in the mouse the Shaker-related K+-channel genes Kcna1, Kcna2, Kcna4, Kcna5, and Kcna6; the Shab-related gene Kcnb1; the Shaw-related gene Kcnc4; and the Shal-related gene Kcnd2. The following localizations were determined: Chr 2, cen-Acra-Kcna4-Pax-6-a-Pck-1-Kras-3-Kcnb1 (corresponding human Chrs 11p and 20q, respectively); Chr 3, cen-Hao-2-(Kcna2, Kcnc4)-Amy-1 (human Chr 1); and Chr 6, cen-Cola-2-Met-Kcnd2-Cpa-Tcrb-adr/Clc-1-Hox-1.1-Myk-103-Raf-1-(Tpi-1, Kcna1, Kcna5, Kcna6) (human Chrs 7q and 12p, respectively). Thus, there is a cluster of at least three Shaker-related K+-channel genes on distal mouse Chr 6 and a cluster on Chr 2 that at least consists of one Shaker-related and one Shaw-related gene. The three other K+-channel genes are not linked to each other. The map positions of the different types of K+-channel genes in the mouse are discussed in relation to those of their homologs in man and to hereditary diseases of mouse and man that might involve K+ channels. 相似文献
3.
A system of non-linear difference equations is used to model the effects of density-dependent selection and migration in a population characterized by two alleles at a single gene locus. Results for the existence and stability of polymorphic equilibria are established. Properties for a genetically important class of equilibria associated with complete dominance in fitness are described. The birth of an unusual chaotic attractor is also illustrated. This attractor is produced when migration causes chaotic dynamics on a boundary of phase space to bifurcate into the interior of phase space, resulting in bistable genetic polymorphic behavior. 相似文献
4.
Improved tests for heterogeneity across a region of DNA sequence in the ratio of polymorphism to divergence 总被引:15,自引:9,他引:6
The neutral theory of molecular evolution predicts that the ratio of
polymorphisms to fixed differences should be fairly uniform across a region
of DNA sequence. Significant heterogeneity in this ratio can indicate the
effects of balancing selection, selective sweeps, mildly deleterious
mutations, or background selection. Comparing an observed heterogeneity
statistic with simulations of the heterogeneity resulting from random
phylogenetic and sampling variation provides a test of the statistical
significance of the observed pattern. When simulated data sets containing
heterogeneity in the polymorphism-to-divergence ratio are examined,
different statistics are most powerful for detecting different patterns of
heterogeneity. The number of runs is most powerful for detecting patterns
containing several peaks of polymorphism; the Kolmogorov-Smirnov statistic
is most powerful for detecting patterns in which one end of the gene has
high polymorphism and the other end has low polymorphism; and a newly
developed statistic, the mean sliding G statistic, is most powerful for
detecting patterns containing one or two peaks of polymorphism with reduced
polymorphism on either side. Nine out of 27 genes from the Drosophila
melanogaster subgroup exhibit heterogeneity that is significant under at
least one of these three tests, with five of the nine remaining significant
after a correction for multiple comparisons, suggesting that detectable
evidence for the effects of some kind of selection is fairly common.
相似文献
5.
6.
Janine JH Oosterhof G Jolanda Elving Ietse Stokroos Arie van nieuw Amerongen Henny C van der Mei Henk J Busscher 《Biofouling》2013,29(6):347-353
The integrity of biofilms on voice prostheses used to rehabilitate speech in laryngectomized patients causes unwanted increases in airflow resistance, impeding speech. Biofilm integrity is ensured by extracellular polymeric substances (EPS). This study aimed to determine whether synthetic salivary peptides or mucolytics, including N-acetylcysteine and ascorbic acid, influence the integrity of voice prosthetic biofilms. Biofilms were grown on voice prostheses in an artificial throat model and exposed to synthetic salivary peptides, mucolytics and two different antiseptics (chlorhexidine and Triclosan). Synthetic salivary peptides did not reduce the air flow resistance of voice prostheses after biofilm formation. Although both chlorhexidine and Triclosan reduced microbial numbers on the prostheses, only the Triclosan-containing positive control reduced the air flow resistance. Unlike ascorbic acid, the mucolytic N-acetylcysteine removed most EPS from the biofilms and induced a decrease in air flow resistance. 相似文献
7.
JH Shazia Fathima Jayaraman Selvaraj Venkatacalam Sivabalan Umapathy Vidhya Rekha Rajagopal Ponnulakshmi Veeraraghavan Vishnupriya Malathi Kullappan Radhika Nalinakumari Sreekandan Surapaneni Krishna Mohan Periyasamy Vijayalakshmi 《Bioinformation》2021,17(1):212
The mTOR (mammalian or mechanistic Target of Rapamycin) is linked with oral cancer. Therefore, it is of interest to study the molecular docking-based binding of paclitaxel (a FDA approved drug for oral cancer) and its analogues with mTOR. Hence, we report the binding features of 10-Deacetyltaxol, 7-Epi-10-deacetyltaxol, 7-Epi-Taxol and 6alpha-Hydroxypaclitaxel with mTOR for further consideration. 相似文献
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