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排序方式: 共有297条查询结果,搜索用时 15 毫秒
1.
Levels of genetic diversity at different stages of the domestication cycle of interior spruce in British Columbia 总被引:3,自引:0,他引:3
M. U. Stoehr Y. A. El-Kassaby 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1997,94(1):83-90
Concerns over the reductionist nature of the domestication of forest-tree species focus on the possibility of potential genetic
erosion during this process. To address these concerns, genetic diversity assessments in a breeding zone the Province of British
Columbia “interior” spruce (Picea glauca×engelmanni) program was conducted using allozyme markers. Genetic-variation comparisons were made between natural and production (seed
orchard) populations as well as seed and seedling crops produced from the same breeding zone’s seed orchard. The natural population
sample consisted of a total of 360 trees representing three stands within each of three watersheds present in the Shuswap-Adams
low-elevation zone of interior British Columbia. Small amounts of genetic differentiation were observed among the nine natural
populations (4%) and this was attributable to extensive gene flow Consequently, the sum of these nine populations was considered as a baseline for the genetic variation present in the breeding
zone. The comparisons between the seed orchard and the breeding zone produced a similar percentage of polymorphic loci while the expected hetrozygosity (0.207 vs 0.210) and the average number of alleles per locus (2.7 vs 2.4) were slightly lower in the seed orchard. A total
of seven natural populations’ rare alleles were not present in the orchard population, while one allele was unique to the orchard. The %P increased to 70.6% in the seedlot, but dropped to the natural populations level (64.7%) in the plantation. The observed increase
in %P was a result of pollen contamination in the orchard. It is suspected that the reduction in the plantation was caused by an
unintentional selection in the nursery. Simulated roguing in the orchard did not drastically reduce even if up to 50% of the orchard’s clones were rogued. However, roguing was associated with a reduction in the average number
of alleles per locus (i.e., sampling effect).
Received: 2 January 1996 / Accepted: 24 May 1996 相似文献
2.
EMBL-Search: a CD-ROM based database query system 总被引:1,自引:0,他引:1
This paper describes a system of generally applicable indexfiles provided on the EMBL sequence databases CDROM tofacilitate the development offronzend software to thesequence databases available on this CDROM. The indexfiles are used by a new versatile and userfriendly databaseretrieval program for the Apple Macintosh, EMBLSearch,which allows the easy construction of complex database queries.EMBLSearch utilizes crossreference informationcontained in the databases to support navigation between differentinformation resources. The ability to run EMBLSearchon a local computer network accessing a shared database CDROMmakes its use particularly cost effective. 相似文献
3.
The effect of neurotensin on submaximally-stimulated hepatobiliary and pancreatic secretion was studied in 6 healthy subjects. An intravenous infusion of neurotensin 1.4 ± 0.3 pmol/kg/min, designed to reproduce plasma neurotensin immunoreactivity levels within the physiological range, produced a significant increase in pancreatic bicarbonate output. Plasma concentrations of pancreatic polypeptide rose by 83 ± 16 pmol/l and were associated with a small reduction in trypsin, but no significant change in bilirubin outputs. 相似文献
4.
Jossi Hillel Martien AM Groenen Michèle Tixier-Boichard Abraham B Korol Lior David Valery M Kirzhner Terry Burke Asili Barre-Dirie Richard PMA Crooijmans Kari Elo Marcus W Feldman Paul J Freidlin Asko M?ki-Tanila Marian Oortwijn Pippa Thomson Alain Vignal Klaus Wimmers Steffen Weigend 《遗传、选种与进化》2003,35(6):533-557
In a project on the biodiversity of chickens funded by the European Commission (EC), eight laboratories collaborated to assess the genetic variation within and between 52 populations from a wide range of chicken types. Twenty-two di-nucleotide microsatellite markers were used to genotype DNA pools of 50 birds from each population. The polymorphism measures for the average, the least polymorphic population (inbred C line) and the most polymorphic population (Gallus gallus spadiceus) were, respectively, as follows: number of alleles per locus, per population: 3.5, 1.3 and 5.2; average gene diversity across markers: 0.47, 0.05 and 0.64; and proportion of polymorphic markers: 0.91, 0.25 and 1.0. These were in good agreement with the breeding history of the populations. For instance, unselected populations were found to be more polymorphic than selected breeds such as layers. Thus DNA pools are effective in the preliminary assessment of genetic variation of populations and markers. Mean genetic distance indicates the extent to which a given population shares its genetic diversity with that of the whole tested gene pool and is a useful criterion for conservation of diversity. The distribution of population-specific (private) alleles and the amount of genetic variation shared among populations supports the hypothesis that the red jungle fowl is the main progenitor of the domesticated chicken. 相似文献
5.
T R Ryder L Y Hu M F Rafferty S M Lotarski D M Rock S J Stoehr C P Taylor M L Weber G P Miljanich E Millerman B G Szoke 《Bioorganic & medicinal chemistry letters》1999,9(16):2453-2458
Selective N-Type Voltage Sensitive Calcium Channel (VSCC) antagonists have shown utility in several models of pain and ischemia. We report the structure-activity relationship at the proximal phenyl group in a series of non-peptidyl VSCC blockers. 相似文献
6.
The existing services of the EMBL Data Library for external users have been improved and extended in several ways. The EMBL File Server has been reorganised, and many new databases and other information relevant to biologists are now accessible via global computer networks. A broad range of software for molecular biology is freely available for different popular computer systems, including the EMBL enhancements to the Wisconsin (GCG) Package. The new Mail-Quicksearch and Mail-FastA services give access to the latest sequence data for database searches by ordinary electronic mail. 相似文献
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10.
AB Zarafi AM Emechebe AD Akpa O Alabi 《Archives Of Phytopathology And Plant Protection》2013,46(4):261-268
Pearl millet downy mildew (DM) incidence, severity and yield losses of two pearl millet varieties (local and improved) due to the disease were determined in the field. Significant differences in the disease incidence and severity were recorded in the plots sown with metalaxyl-treated seeds and those sown with non-treated seeds, indicating the efficacy of the fungicide on the fungus. Yield losses due to non-treatment of seeds with metalaxyl was 40.88 and 45.39% in a local variety and 43.00 and 18.60% in an improved variety in the 2000 and 2001 cropping seasons respectively. Significant differences between plots sown with metalaxyl-treated and those sown with non-treated seeds were obtained for other yield components such as 1000-grains weight, panicle length and weight. 相似文献