Full-text resources of PSJD and other databases are now available in the new Library of Science.
Visit https://bibliotekanauki.pl
Preferences help
Polish version English version Language
enabled [disable] Abstract
Number of results

Results found: 16

Number of results on page
first rewind previous Page / 1 next fast forward last

Search results

Search:
in the keywords:  SELECTION
help Sort By:

help Limit search:
first rewind previous Page / 1 next fast forward last
1

Differentially expressed genes in adipose tissues of high body weight-selected (obese) and unselected (lean) mouse lines

100%
Aksu S., Koczan D., Renne U., Thiesen H.-J., Brockmann G. A.
Journal of Applied Genetics
|
2007
|
vol. 48
|
issue 2
133-1431
EN
Recently, quantitative trait loci (QTLs) for body weight and obesity have been mapped in an intercross population between the high body weight-selected mouse line DU6i and the inbred line DBA/2. Most QTLs were highly significant, but had small effects only. Under the hypothesis that small-effect QTLs might result from changes in gene activity, our strategy to identify candidate genes for the observed effects was directed towards the identification of differentially expressed genes. Therefore, here we compare the transcription profile of about 11 000 genes in epididymal fat tissues of males of two high body weight-selected (DU6 and DU6i) and two unselected mouse lines (DUKs and DBA/2). For the hybridisation of GeneChips, we used pooled samples of 20 individual mice. By pair-wise comparisons between selected and unselected mouse lines, a set of 77 genes was identified representing genes whose level of expression differed between obese and lean mouse strains. According to the functional classification of genes, 69 differentially expressed genes were involved in regulatory and metabolic pathways, cell division, cell stability, or immune response, and thus might have an effect on body weight and fat accumulation. 14 out of these genes, occur in QTL regions for body weight or abdominal fat weight. Further analyses are necessary to discriminate between genes directly causing QTL effects and indirectly regulated differentially expressed genes.
2

Effects of dietary crude protein on slaughter yield of selected broiler stocks

100%
Melo J. E., Miquel M. C., Mallo G., Ciacciariello M., Villar E.
Journal of Applied Genetics
|
1999
|
vol. 40
|
issue 3
219-231
EN
The objective of this paper was to determine the differences in yield and body composition between a commercial strain (COM) and a weakly selected strain (FR) of broilers at two slaughter ages on diets differing in protein content. There were 306 males reared on litter floor pens, fed ad libitum, and randomly assigned to 16 pens in a 2 x 2 factorial design with 4 repetitions. The diets were HP (high protein): 20.5% protein to 6 weeks of age and 16.9% from then on; LP (low protein): 16.9% protein all the time. At 50 and 71 days, four broilers from each pen were taken at random, fasted, killed, slaughtered and the following weights were recorded: live weight, eviscerated carcass, abdominal fat, feathers, blood, small intestine, large intestine, gizzard, proventriculus, liver, breast, thighs and heart. Analyses of variance for traits and for their proportions to live weight were done. The model included genotype, diet, genotype x diet and replicate. The genotypes differed in live weight and growth patterns, COM showing a higher proportion of commercial cut weight and FR a higher digestive organ and relative feather weight at older ages. The low protein diet affected COM genotypes more than FR genotypes, probably because there was a difference in protein requirements.
3

In vitro shoot regeneration of strawberry as the source of somaclonal variants resistant to verticillium wilt?

100%
Sowik I., Wawrzynczak D., Michalczuk L.
Biotechnologia
|
2001
|
issue 1
131-133
EN
Somaclonal variants of strawberry resistant to verticillium wilt were selected by cocultivation of shoots of various cultivars obtained by both micropropagation and regeneration from a callus with a homogenate of 3-week-old liquid culture of mixed isolates of Veriticillium dahliae. There was a large variation in the resistance to the pathogen within a population of both micropropagated and regenerated from the callus shoots. After 70 days of cocultivation most of the shoots of susceptible cultivars were heavily damaged or dead, but there were some individuals that survived in a relatively good health. Those variants were transplanted on a new Boxus?s medium supplemented with 2 mg/l of benomyl to eliminate pathogen and their resistance to verticillium wilt is now tested.
4

Genetic differentiation induced by selection in an inbred population of the silkworm Bombyx mori, revealed by RAPDand ISSR marker systems

100%
Pradeep A. R., Chatterjee S. N., Nair C. V.
Journal of Applied Genetics
|
2005
|
vol. 46
|
issue 3
291-298
EN
Artificial selection has been widely utilized in breeding programmes concerning the commercially important silk-producing insect Bombyx mori. Selection increases the frequency of homozygotes and makes homozygous effects stronger. Molecular variation induced by selection in the inbred population of B. mori strain Nistari, was assessed in terms of genic differentiation by using a polymorphic profile generated by RAPD and ISSR marker systems. Artificial selection for longer larval duration (LLD) for 4 generations resulted in a significant prolongation of larval duration (F = 89.28; P = 5.14?10?7). The lines selected for shorter larval duration (SLD) were not significantly different from the control group. RAPD and ISSR primers generated polymorphic profiles when amplified with genomic DNA of individuals of LLD and SLD lines. Distinct markers specific to LLD individuals were observed from the 3rd generation and indicated selection-induced differentiation of allelic variants for longer larval duration. Both SLD and LLD were characterized by high gene diversity (h 0.197) and total heterozygosity (Ht 0.26), low homogeneity (?2 test, p < 0.005) as well as a large coefficient of gene differentiation (Gst 0.42) but low gene flow (Nm 0.42). Genetic distance was the highest (0.824) between 3rd generations of SLD and LLD. High heterozygosity and prolonged larval duration substituted for shorter larval duration (the traditional trait of fitness) in the Nistari LLD larvae.
5

Development and selection of T Cells: how many subsets? how many rules?

100%
Kisielow P.
Archivum Immunologiae et Therapiae Experimentalis
|
2003
|
vol. 51
|
issue 6
407-414
EN
Since the discovery indicating that thymus derived lymphocytes (T cells) can be divided into two subpopulations: CD8+ (killer) and CD4+ (helper) cells, subsequent studies revealed bewildering heterogeneity of T cells. In the present review an attempt is made to present the actual picture of T cell heterogeneity, introduce some order into nomenclature and summarize the rules behind the development and selection of different, currently recognized T cell subsets.
6

Application of molecular markers in vegetable crops breeding

100%
Baranski R., Szklarczyk M., Grzebelus D., Jagosz B.
Biotechnologia
|
2001
|
issue 1
47-50
EN
Molecular markers have been introduced to breeding programmes of vegetables in recent years in Poland. Research done at Dept. of Genetics, Plant Breeding and Seed Science, Agricultural University of Krakow allowed to implement molecular techniques useful in marker assisted selection, assessment of genetic purity of breeding lines and hybrids, and estimation of genetic similarity between breeding materials.
7

Curvilinear inbreeding effects on some performance traits in laying hens

100%
Szwaczkowski T., Cywa-Benko K., Wezyk S.
Journal of Applied Genetics
|
2004
|
vol. 45
|
issue 3
341-342
EN
Quadratic partial regression coefficients were estimated for the inbreeding level on five performance traits (body weight, average egg weight, age at first egg, percentage of fertilized eggs, and hatchability of set eggs) of two strains of laying hens. Data on 5631 of H77 layers and 3563 of N88 layers from nine consecutive generations were analysed. Only dams were accounted for. Partial regression coefficients were estimated by REML with a single-trait animal model, which included fixed effects (generation and hatching period) and random effects (additive genetic and error effects). The mean inbreeding level was 0.87% in strain H77 and 1.08% in strain N88. The inbreeding effects were analysed based on the quadratic partial regression equations. A slight inbreeding depression was found for all the traits analysed in N88. In strain H77, negative effects of inbreeding were only noted for body weight and average egg weight. The small inbreeding effects shown here resulted from a relatively low level of homozygosity in the populations studied. The strains were found to differ in the effects of inbreeding. It is worth pointing out that differences were noted both between the inbreeding depression estimated from the partial linear regression equation and the quadratic partial regression equation, as well as different inbreeding levels.
8

Screening methods of industrial strain mutants

88%
Galas E., Kwapisz E., Polak J.
Biotechnologia
|
1995
|
issue 3
104-119
EN
The screening methods used for improvement of industrial strains are presented.Two general categories of methods have been distinguished: random screening and rational screening.Major techniques employed in rational screening are based on the selection of auxotropic mutants, reverants of non-producers, strain resistant to some factors like toxic analogues of metabolism intermediates, induction and catabolite regression or end-product inhibition, mutants with modified cell wall permeability and microorganisms tolerating somenutrients and precursors of secondary metabolites.
9

Direct effects of cyclic selection fo longer seminal roots in spring barley (Hordeum vulgare L.)

88%
Gorny A. G.
Journal of Applied Genetics
|
1995
|
vol. 36
|
issue 1
17-26
EN
Cyclic pedigree selection for longer seminal roots was performed in the F2, F3 and F4 generations of hybrid population of spring barley.The total length of roots was measured in seedlings grown in filter-paper rollers.The intensity of selectio was 20% (C1, C2 cycles) and 26% (C3).Selection wasceffective.On anaverage, the finally selected F5-pedigrees formed 6% longer seminal roots system than the initial F2's and much of them exibited 7-16% improved rooting when compared with the best parent in a sand-vermiculite pot culture.Realized heritability coefficient of the root length ranged from 0.21 to 0.37 when assessed by the ratio of selection response to selection differential, while those estimated by the parent-offspring regressions attained 0.40-0.53.The obtained results suggest that progeny evaluation and/or seletion delayed for later generations should be essential for more effective root selection in barley.
10

Selection for high erucic acid content in winter oilseed rape (Brassica napus L.) on microspore-derived embryos

88%
Cegielska-Taras T., Szala L., Naleczynska A., Kolodziej K., Orodowczyk M.
Journal of Applied Genetics
|
1999
|
vol. 40
|
issue 4
305-315
EN
Application of doubled-haploid (DH) techniques combined with a method of early selection for erucic acid in cotyledons of microspore-derived embryos (MDEs) from three hybrids of winter oilseed rape (high erucic acid and low glucosinolates) was described. Comparisons of erucic acid content between MDEs and seeds from the same homozygous line DH-Gr85 demonstrated that seed-specific fatty acid composition can be fully stimulated in MDEs after 18 days of culture on the NLN-medium with 0.8% agar and 2% sucrose with or without 10 mM ABA. The erucic acid content (percentage of the total fatty acid content) of cotyledons of embryos from three hybrids and of the seeds derived from plants regenerated from the remaining parts of the embryos were highly correlated (r = 0.78**).
11

A correlated response to selection of mice based on progeny or performance test

88%
Sobczynska M., Kownacki M.
Journal of Applied Genetics
|
1995
|
vol. 36
|
issue 1
49-58
EN
A comparison was made of a correlated response to selection between populations of mice selected for body weight at weaning on the basis of their own performance or their progeny.Selection was conducted throughout 15 generations andduring the last two generations, three replicas were crossed within each group.A correlated response to selection of the body weight on day 42, weights gains between day 21 and 42 and litter size at birth was significantly higher in the group of mice evaluated on the basis of their progeny.A negative correlated response occured in the litter size at birth in the group evaluated on the basis of animals' own performance.The realized genetic correlations in the group evaluated on the basis of animals' own performance was 0.9, 0.1 and 0.8 respectively, between the body weight on day 21 and 42, body weight on day 21 and weight gains between day 21 and 42, body weight on day 21 and litter size at birth.
12
Content available remote

Selection for body weight induces differences in exploratory behavior and learning in mice

88%
Wirth-Dzieciolowska E., Lipska A., Wesierska M.
Acta Neurobiologiae Experimentalis
|
2005
|
vol. 65
|
issue 3
243-253
EN
Mice that were selected for over 108 generations for body weight at the postnatal (PN) day 21 were examined in the open field (OF) test and in the Lashley maze (LM) for their exploratory behavior and spatial learning. Light (L), heavy (C) and control (K) lines of mice in three age groups: PN-21, PN-56 and PN-90, were tested once in the OF and three times in the LM. During the session in the OF the L mice displayed a steady increase of behavioral activity (sum of locomotion and rearing, climbing, sniffing, and grooming acts), whereas mice C and K habituated in the last stage. During entire session in the OF activity of the L mice was lower than that of the C and K mice. The L mice displayed high defecation/urination scores. In the learning task the L mice performed worse than the C and K mice. In conclusion, behavior of the L line was different from that of the two other lines: they showed higher anxiety and poorer spatial learning.
13

Evaluation of the response to limited water, nitrogen and phosphorus supply in spring barley genotypes selected for vigorous seminal roots

75%
Gorny A.
Journal of Applied Genetics
|
1996
|
vol. 37
|
issue 1
11-27
EN
Fourteen F5- and F6-pedigrees previously selected for a more vigorous seminal root system in a cross population of spring barley, were compared with their parents in the response to severe post-sowing drought and limited N- and P-supply.The materials were studied in glass-faced soil boxes, sand-vermiculite cultures and in the field.The F5's juvenile rooting superiority was not totally preserved for further growth stages suggesting partly different genetic backgrounds responsible for the seminal root system at various growth stages.Results indicated an absence of close genetic correlations between the seminal and adventitious root systems.The selected spring barley pedigrees exibiting a more vigorous rooting benefit much more for their ability to avoid drought conditions than for their tolerance to nitrogen and phosphorus limitations.Especially under decreased N availability the enhanced root extension in F5s resulted in a depressed shoot dry matter production.Despite a relatively low differentiation in the grain yield, some of the selected F6-pedigrees were simultameously found to indicate a high yield potential, an improved stability or tolerance to low-input.
14

Environmental stability and heritability estimates for grain yield and test weight in triticale

75%
Barnett R. D., Blount A. R., Pfahler P. L., Bruckner P. L., Wesenberg D. M., Johnson J. W.
Journal of Applied Genetics
|
2006
|
vol. 47
|
issue 3
207-213
EN
Hexaploid triticale has many advantages over both parental species for both grain and forage production in certain environments. Additional information on environmental stability and heritability would be desirable to develop appropriate selection strategies in the production of superior widely-adapted cultivars. The grain yield of 22 diverse genotypes grown at four ecologically-distinct geographical locations [Quincy, FL, USA (approximate geographical coordinates (AGC) = 30oN 84oW, approximate elevation (AE) = 58 m), Plains, GA, USA (AGC = 32oN 84oW, AE = 76 m), Bozeman, MT USA (AGC = 45oN 111oW, AE = 1458 m), and Aberdeen, ID, USA (AGC = 42oN 112oW, AE = 1360 m)] was measured in two years with winter and spring planting dates only at Bozeman and Aberdeen. Test weight (grain weight in a given volume) was determined for two years at Bozeman and Aberdeen at both planting dates and one year at Quincy. Stability analyses indicated that significant (P < 0.01) variation in means, regression coefficients, and deviation mean squares of the genotypes were present for both characters. Realized heritability (h2) estimates were as follows: grain yield ranged from ?0.02 to 0.80 with a mean of 0.57; test weight ranged from 0.63 to 1.05 with a mean of 0.93. The results indicated that substantial genetic variation is present and selection for widely-adapted cultivars would be effective for both characters especially test weight.
15

Microspore culture of winter oilseed rape (Brassica napus L.) in conjunction with other in vitro technologies

75%
Cegielska-Taras T., Szala L., Bartkowiak-Broda I.
Biotechnologia
|
2001
|
issue 1
81-86
EN
Microspore culture in conjuction with other technologies such as selection, mutagenesis and transformation has been used for the production of novel genotypes of Brassica napus L. for crop improvement. The example of in vitro selection of microspore - derived embryos includes: a) ploidy level, b) seed oil composition (for example: high level of erucic acid), c) genotypes with restorer gene for CMS-ogura system (by means of isozyme marker PGI-2 ), d) herbicide resistant forms. Efficiency of microspore mutagnesis has been tested by the treatment of freshly isolated microspores with UV and MNU. Direct delivery of foreign gene to the microspores (microprojectile bombardment) combined with the use of Agrobacterium tumefaciens to microspore derived embryos seems to be a promising way of oilseed rape transformation.
16

Generation of selectable marker-free transgenic plants

75%
Zuzga S., Burza W., Malepszy S.
Biotechnologia
|
2003
|
issue 4
32-46
EN
Since the first reports of successful plant transformation appeared, there have been steady improvements of the transformation methods. Nowadays, transgenic plants without the incorporation of selection genes for antibiotic or herbicide resistance would be the only ones acceptable to the public, so elimination of these genes from transgenic crops prior to their field release and commercialization seems inevitable. Several strategies have been developed to generate marker-free transgenic plants, including: positive selection, alternative marker genes, co-transformation, site-specific recombination, transpozon-mediated approaches and intrachromosomal homologous recombination. The efficiency of these methods is various as comparing to the traditional marker assisted selection - higher in case of alternative procedures and lower in others.
first rewind previous Page / 1 next fast forward last
JavaScript is turned off in your web browser. Turn it on to take full advantage of this site, then refresh the page.