Stock Selection
Mostrando 25-36 de 61 artigos, teses e dissertações.
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25. Low variation in ribosomal DNA and internal transcribed spacers of the symbiotic fungi of leaf-cutting ants (Attini: Formicidae)
Leaf-cutting ants of the genera Atta and Acromyrmex (tribe Attini) are symbiotic with basidiomycete fungi of the genus Leucoagaricus (tribe Leucocoprineae), which they cultivate on vegetable matter inside their nests. We determined the variation of the 28S, 18S, and 5.8S ribosomal DNA (rDNA) gene loci and the rapidly evolving internal transcribed spacers 1 a
Brazilian Journal of Medical and Biological Research. Publicado em: 2004-10
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26. Morphological genetic markers for selection of broiler lines
Two paternal broiler lines (LL and LLc, originated from the same stock in 1998) of Embrapa Suinos e Aves genetic program were used. Line LL had been selected for eight generations for rapid growth while LLc had been mated randomly, without selection, as a control line. In the last generation, 30 males and 240 females were used in hierarchical matings with pe
Revista Brasileira de Ciência Avícola. Publicado em: 2003-12
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27. Soil carbon sequestration - Evaluation of its potential in pastures on sandy soils, Anhembi - Piracicaba/SP / Seqüestro de carbono nos solos - Avaliação das potencialidades dos solos arenosos sob pastagens, Anhembi - Piracicaba - SP"
The project studied the potential for soil carbon sequestration in pastures growing on sandy soils in the Cerrado region and for the application of remote sensing techniques for estimating carbon sequestration levels. The main focus was deducing how many tons per hectare could be sequestered if better pasture management techniques were adopted. Four pastures
Publicado em: 2003
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28. Idade, crescimento e avaliaÃÃo de estoque da serra Scomberomorus brasiliensis (Teleostei: Scombridae), na plataforma continental do Nordeste do Brasil
The spanish mackerel, Scomberomorus brasiliensis, represents an important fishery resource in Northeast Brazil. Aiming to analyze the age structure composition of the artesanal fisheries catches and to assess the stocks in the area, 6148 specimens were sampled at the continental shelf between 1998 and 2001. This activity was carried out in the extent of the
Publicado em: 2002
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29. P Element Transposition Contributes Substantial New Variation for a Quantitative Trait in Drosophila Melanogaster
The P-M system of transposition in Drosophila melanogaster is a powerful mutator for many visible and lethal loci. Experiments using crosses between unrelated P and M stocks to assess the importance of transposition-mediated mutations affecting quantitative loci and reponse to selection have yielded unrepeatable or ambiguous results. In a different approach,
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30. Differential Response to Selection on the Two Sexes in DROSOPHILA MELANOGASTER
Artificial selection for short wing was performed in two Drosophila melanogaster populations with partially different gene pools: the C populations were derived from a Canton stock while the H lines were derived from a cross between Canton and a b, cn, vg strain. It is shown that in both populations selection on females (CF, HF) was more effective than selec
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31. Transforming variants of the avian myc-containing retrovirus FH3 arise prior to phenotypic selection.
The avian retrovirus FH3, which encodes a Gag-Myc fusion protein, transforms chicken macrophages but not fibroblasts. However, passage of FH3 viral stock in fibroblasts leads to emergence of a virus capable of fibroblast transformation. This virus has not acquired myc mutations; instead, it carries internal gag deletions which confer the ability to transform
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32. Selection of Galactose-Fermenting Streptococcus thermophilus in Lactose-Limited Chemostat Cultures
Stock cultures of Streptococcus thermophilus are essentially galactose negative (Gal−). Although both galactose 1-phosphate uridyl transferase and uridine-5-diphospho-glucose 4-epimerase are present, suggesting that the genes for the Leloir pathway exist, cells cannot induce high levels of galactokinase. Therefore, galactose is largely excreted when cultur
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33. Two Mutators and Their Suppressors in DROSOPHILA ANANASSAE
Assays of seven mutant stocks exposed a ten-fold range in spontaneous Minute mutation frequencies. Genetic analysis of the difference between the px (0.0006 Minutes) and bri (0.0042 Minutes) stocks revealed that each of these stocks lacks one of two complementary, autosomally transmitted, maternally expressed, dominant suppressors of a dominant 3-linked muta
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34. Inheritance of a secondary sexual character in Drosophila silvestris.
Reciprocal crosses were carried out between laboratory stock specimens obtained from two races of Drosophila silvestris from the island of Hawaii that differ in a quantitative secondary sexual character. The race from the Hilo side of the island has a novel attribute, consisting of an extra row of cilia on the tibia of males, which is used during courtship.
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35. What Can Be Learnt about Selection from Gene Frequency Distribution?
Polymorphism has been studied at the Esterase 6 locus in the Yellow Fever mosquito Aedes aegypti (L.) in laboratory stocks. At least 12 alleles are present, with up to four coexisting in a stock. The allele frequency distribution is quite sharply peaked at a mode of about 0.25. The experimental data are compared with the results of simulation based on two mo
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36. Rhizobium meliloti competitiveness and the alfalfa agglutinin.
We have isolated two types of isolates having identical colony morphologies from stock cultures of two different Rhizobium meliloti strains. One isolate was agglutinated at a high-dilution titer (HA, highly agglutinable) of the alfalfa agglutinin and was sensitive to phage F20, and the other was agglutinated at a lower agglutinin titer (LA) and was sensitive