全文获取类型
收费全文 | 133篇 |
免费 | 0篇 |
国内免费 | 4篇 |
出版年
2019年 | 1篇 |
2018年 | 3篇 |
2014年 | 2篇 |
2013年 | 2篇 |
2012年 | 1篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 18篇 |
2008年 | 22篇 |
2007年 | 10篇 |
2006年 | 6篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 2篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 2篇 |
1999年 | 2篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有137条查询结果,搜索用时 78 毫秒
41.
Microsatellites in Cassava (Manihot esculenta Crantz): discovery, inheritance and variability 总被引:2,自引:0,他引:2
P. P. Chavarriaga-Aguirre M. M. Maya M. W. Bonierbale S. Kresovich M. A. Fregene J. Tohme G. Kochert 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(3):493-501
Fourteen microsatellites containing GA-repeats were isolated and characterized in cassava (Manihot esculenta Crantz, Euphorbiaceae). Microsatellite heterozygosity (h) was estimated in 48 accessions using (32P)-end-labeled primers and in more than 500 accessions using fluorescence-based genotyping. Heterozygosity values ranged from
0.00 to 0.88 and the number of alleles detected varied from 1 to 15. The reproducibility of allele sizing was also assessed
using fluorescence-based genotyping. The average inter-gel size difference was 1.03 nucleotides. Chi-square tests (χ2) were performed to analyse segregation distortion and the linkage between alleles segregating from either or both parents
in an F1 mapping population. Most microsatellite loci segregated in the expected 1 : 1, 1 : 2 : 1 or 1 : 1 : 1 : 1 ratio. Linkage
was detected between loci segregating from either parent, and segregation distortion from the male parent was detected for
locus GA-131. Approximately 80% of the microsatellites detected one or two alleles per accession, suggesting a low degree
of microsatellite locus duplication, an unexpected finding for a putative allopolyploid, highly heterozygous species. The
high h values of most microsatellites, their amplification in other Manihot taxa and their suitability for high-throughput, fluorescence-based genotyping, make microsatellites the marker of choice
for germplasm characterization and saturation of the cassava map.
Received: 4 September 1997 / Accepted 16 March 1998 相似文献
42.
The effect of population structure on the relationship between heterosis and heterozygosity at marker loci 总被引:5,自引:0,他引:5
A. Charcosset L. Essioux 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(2-3):336-343
The relationship between heterozygosity at neutral marker loci and heterosis of F1 hybrids is investigated using a theoretical model. Results emphasize that linkage disequilibrium between the markers and the loci implicated in heterosis [quantitative trait loci (QTLs) that exhibit dominance effects] is a necessary condition to finding a correlation (
mh
) between heterozygosity at marker loci and the heterosis. The effect of population structure, in which the parental inbred lines of the hybrids belong to different heterotic groups, is considered.
mh
is investigated for: (1) hybrids between lines that belong to the same heterotic group (within-group hybrids); (2) hybrids between lines that belong to different groups (between-group hybrids); and (3) all hybrids, both within and between-groups. Within a group, significant values of (
mh
) may arise because of linkage disequilibrium generated by drift. At the between-group level, no correlation is expected since link-age disequilibrium should differ randomly from one group to the other, which is consistent with recent experimental results. Possible ways to achieve prediction of the heterosis in this situation are discussed. When all hybrids are considered simultaneously, divergence of allelic frequencies among groups for the markers and the QTLs produces a correlation between heterosis and heterozygosity at marker loci. This correlation increases with the number of markers that are considered. 相似文献
43.
R. Frankham G. J. Smith D. A. Briscoe 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1993,86(8):1023-1027
The effects of inbreeding, with (IS) and without selection (IO) for reproductive fitness, on inbreeding depression and heterozygosity were evaluated in 20 lines of each treatment inbred over seven generations using full-sib mating. The survival of lines was significantly greater in IS (20/20) than in IO (15/20). The competitive index measure of reproductive fitness was significantly lower in the inbred lines than in the outbred base population, but not significantly different in surviving IS and IO lines. There was a trend for higher fitness in the IS treatment as relative fitnesses were 19% higher in IS than IO for surviving lines and 59% higher for all lines. Heterozygosities were lower in the inbred lines than in the base population, and significantly higher in the IS than the IO lines. Consequently, the reduction of inbreeding depression in IS has been achieved, at least in part, by slowing the rate of fixation. 相似文献
44.
Ranajit Chakraborty 《Journal of molecular evolution》1977,9(4):313-322
Summary Monte Carlo simulations are performed to compare the predictions based on the two presently used theoretical models for studying genetic variations in natural populations, the infinite allele model and the stepwise mutation model. Distribution of heterozygosity is noticed to be similar under these models until the product of population size and mutation rate is large. It is seen that electromorphs with high population frequency usually contain older alleles (at the codon level) than an electromorph of low population frequency. The interpretations of these results in explaining the allelic variations at electrophoretic level is also discussed.Research supported by U.S. Public Health Service General Research Support Grant 5 SO 5 RR 07148 from the University of Texas Health Science Center, Graduate School of Biomedical Sciences, Houston, Texas 相似文献
45.
C. M. M. Meireles M. I. C. Sampaio H. Schneider M. P. C. Schneider 《Primates; journal of primatology》1992,33(2):227-238
The electrophoretic patterns of 15 protein systems codified for 20 genetic loci were investigated using horizontal electrophoresis.
A total of 150 blood samples, from five species of the genusCallithrix were analyzed. Polymorphic variation was observed in 10 out 20 loci analyzed. The genotypic distributions are in Hardy-Weinberg
equilibrium. The average heterozygosity (H) varied from 1% to 5%, similar to those observed for other Neotropical primates.
The genetic distance coefficients revealed a phylogenetic separation of these species into two groups: (1) “argentata” (C. humeralifer andC. emiliae); (2) “jacchus” (C. jacchus, C. penicillata, andC. geoffroyi). This arrangement is according to the taxonomic arrangement proposed byHershkovitz (1977),de Vivo (1988), andMittermeier et al. (1988). The results in each group are compatible with the subspecies values recorded for the Platyrrhini. These values
showed that:C. humeralifer andC. emiliae are subspecies ofC. argentata;C. jacchus, C. penicillata, andC. geoffroyi are subspecies ofC. jacchus. These results also suggest thatC. j. geoffroyi is the “jacchus” group taxon, most similar genetically to the “argentata” group. 相似文献
46.
Dale D. Dykes M. H. Crawford H. F. Polesky 《American journal of physical anthropology》1983,62(2):137-145
Gc subtypes of 20 North and Central American populations and PCM1 subtypes in 11 populations were analyzed to identify interpopulation variation of the respective gene frequencies for common alleles. A total of 23,304 phenotypings were done. Absolute heterozygosity levels (D) generally increased twofold when phenotyping by isoelectric focusing was compared with conventional electrophoresis. Graphic representation of the Gc subtypes and multivariate analysis to identify genetic affinities of the populations under study reveal genetic clusters consistent with major historical and geographical groupings of man. 相似文献
47.
48.
Atriplex tatarica is an annual, early successional, facultative halophilic species of frequently disturbed human-made habitats in Central and Eastern Europe. We investigated to what extent the plants grown from seeds extracted from soil seed bank differed genetically to mature aboveground plants in experimental populations of A. tatarica over two successive years. At each of five plots 50 aboveground plants and 50 plants extracted from seeds stored in soil were assayed for allozyme analysis in 2003 and 2004. At the start of experiment, we introduced 1000 seeds of the study species into each of five experimental plots. While the species dominated in all of the experimental plots in the first year, the second year A. tatarica coverage decreased dramatically. Overall allele frequencies of soil seeds and mature plants showed significant differences between life history stages in both years, but not within years in soil seeds as well as mature plants stages. While mature plants showed a significantly greater amount of single and multilocus heterozygosity in both consecutive years, comparison between years did not yield any significant differences. In the same way, despite a relatively large seed bank the species population genetic parameters, i.e. allelic richness (A), observed heterozygosity (Ho), gene diversity (Hs), inbreeding coefficient (FIS) and fixation index (FST), did not change over years between as well as within life history stages. The soil seeds and mature plants significantly differed in Ho, Hs and FIS, while the A and FST were not significantly different between life history stages. 相似文献
49.
50.
Measures of genetic parental distances (GPD) based on microsatellite loci (D (2) and IR), have been suggested to be better correlated with fitness than individual heterozygosity (H), as they contain information about past events of inbreeding or admixture. We investigated if GPD increased with increasing genetic divergence between parental populations in Drosophila buzzatii and if the measures indicate past events of admixture. Further we evaluated the relationship between GPD, fitness and fluctuating asymmetry (FA) of size and shape. We investigated three populations of Drosophila buzzati, from Argentina, Europe and Australia. From these populations two intraspecific hybridisation lines were made; one between the Argentinean and European populations, which have been separated 200 years and one between the populations from Argentina and Australia, which have been separated 80 years. By doing this we obtained hybrid progeny having different levels of GPD. We found that D (2) and H can be used as indicators of admixture when comparing hybrid individuals with their parentals. IR was not informative. Our results does not exclude the presence of genetic fitness correlations (GFC) over individuals with a broad fitness range from populations in equilibrium, but we doubt the presence of GFC using GPD measures in admixed populations. Shape FA could be a relevant measure for fitness, however, only when comparing populations, not at individual level. 相似文献