Biological variation

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  • Recent studies have shown that differences in life history may lead to consistent inter-individual variation in behavioural traits, so-called behavioural syndromes, animal personalities or temperaments. Consis- tencies of behaviours and behavioural syndromes have mainly been studied in non-cooperative species. Insights on the evolution of coopera- tion could be gained from studying individual differences in life histories and behavioural traits.

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  • There are lexical, syntactic, semantic and discourse variations amongst the languages used in various biomedical subdomains. It is important to recognise such differences and understand that biomedical tools that work well on some subdomains may not work as well on others. We report here on the semantic variations that occur in the sublanguages of two biomedical subdomains, i.e. cell biology and pharmacology, at the level of named entity information.

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  • Department of Genome Sciences, Life Sciences Division, Lawrence Berkeley National Laboratory, One Cyclotron Rd, Berkeley, CA 94720, USA. †Department of Biology, University of Pennsylvania, 324 Leidy Laboratories, Philadelphia, PA 19104, USA. ‡Center for Integrative Genomics, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720, USA. §Current address: Department of Genetics, Washington University, 4566 Scott Ave, St. Louis, MO 63110, USA. Correspondence: Justin C Fay. E-mail: jfay@genetics.wustl.

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  • Chapter 11 - Genome-wide variation and trait analysis. This chapter presents the following content: Genetic variation among individual genomes, single nucleotide polymorphisms (SNPs) and small-scale-length variations, deletions or duplications of a DNA region, positional cloning: from DNA markers to disease-causing genes, genome-wide association studies.

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  • Chapter 19 - Variation and selection in populations. This chapter involves the study of how genetic laws impact the genetic makeup of a population. Mendelian principles are the basis for the Hardy-Weinberg law which allows one to calculate allele and genotype frequencies from one generation to the next. The Hardy-Weinberg law can be used only if other forces are not acting on the allele frequency. Those forces include selection, migration, mutation, and population size.

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  • Published: 12 March 2004 Genome Biology 2004, 5:318 The electronic version of this article is the complete one and can be found online at © 2004 BioMed Central Ltd reports A report on the 2004 Keystone Symposium ‘Human Genome Sequence Variation and the Inherited Basis of Common Disease’, Breckenridge, USA, 8-13 January 2004. General Hospital, Boston, USA) described a genetic analysis of diabetes. He showed preliminary results suggesting that mitochondrial DNA is involved in type II diabetes and hypothesized that primary...

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  • Chapter 13 - Meiosis and sexual life cycles. This chapter distinguish between the following terms: somatic cell and gamete, autosome and sex chromosomes, haploid and diploid; describe the events that characterize each phase of meiosis; describe three events that occur during meiosis I but not mitosis; name and explain the three events that contribute to genetic variation in sexually reproducing organisms.

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  • Chapter 23 - The evolution of populations. In this chapter, you should be able to: Explain why the majority of point mutations are harmless; explain how sexual recombination generates genetic variability; define the terms population, species, gene pool, relative fitness, and neutral variation; list the five conditions of Hardy-Weinberg equilibrium;...

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  • The topics discussed in this chapter are: What facts form the base of our understanding of evolution? What are the mechanisms of evolutionary change? What evolutionary mechanisms result in adaptation? How is genetic variation maintained within populations? What are the constraints on evolution? How have humans influenced evolution?

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  • In this chapter, students will be able to understand: Contrast haploid and diploid chromosome numbers, explain what is meant by homologous chromosomes, describe the role of crossing-over in contributing to genetic variation, define independent assortment and describe how it contributes to genetic variation in the offspring,...

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  • This chapter include objectives: Evaluate the effects of continuous variation, pleiotropic genes, lack of complete dominance, environmental modifications of genes, and epistasis on disease; understand the importance of crossing over in terms of gene assortment and construction of genetic maps; describe the many genetic disorders discussed in the text, their symptoms, relative frequency in specialized populations, and their genetic basis;...

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  • This chapter students will be able to: Recognize that natural selection is the correct mechanism for explain evolution; understand the importance of and identify sources of genetic variation; know how to solve various problems associated with Hardy-Weinberg equilibrium; list the five factors, and state an example of each, that affect Hardy-Weinberg equilibrium and understand how each can produce evolutionary changes in a population experiencing any one of the five;...

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  • Whereas the mechanical performance of plant organs has often been discussed in evolutionary biology [1,2], tree biomechanics has rarely been considered in the context of functional ecology. Functional ecology aims at understanding the functions of organisms that result in fluxes of biomass or energy within an ecosystem, e.g., a forest. This discipline studies the processes controlling these fluxes, at either the scale of an individual, community, or ecosystem, with their response to natural or anthropic environmental variations....

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  • Tissue culture was first devised at the beginning of the twentieth century [Harrison, 1907; Carrel, 1912] (Table 1.1) as a method for studying the behavior of animal cells free of systemic variations that might arise in vivo both during normal homeostasis and under the stress of an experiment. As the name implies, the technique was elaborated first with undisaggregated fragments of tissue, and growth was restricted to the migration of cells from the tissue fragment, with occasional mitoses in the outgrowth.

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  • Quantification of Drug Action the dose at which one-half of the group has responded. The dose range encompassing the dose-frequency relationship reflects the variation in individual sensitivity to the drug. Although similar in shape, a dose-frequency relationship has, thus, a different meaning than does a dose-effect relationship. The latter can be evaluated in one individual and results from an intraindividual dependency of the effect on drug concentration.

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  • The determination of enzyme AChE continues to be widely used to measure the exposure to OF and C, however, interpretations of results are highly variable, since there are genetic and physiological causes as well as associated pathologies, which can decrease the levels of this enzyme (Varona et al, 2007).

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  • Genetics is the science of genes, heredity, and the variation of organisms.[37][38] Genes encode the information necessary for synthesizing proteins, which in turn play a large role in influencing (though, in many instances, not completely determining) the final phenotype of the organism. In modern research, genetics provides important tools in the investigation of the function of a particular gene, or the analysis of genetic interactions. Within organisms, genetic information generally is carried in chromosomes, where it is represented in the chemical structure of particular DNA molecules....

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  • Why a book on cutaneous vascular proliferations? There are several compelling reasons to justify the existence of a book on this topic. One of the most important is that cutaneous vascular proliferations are exceedingly common and affect a large number of individuals of both sexes and within a wide age range. They make up a broad spectrum of lesions with morphological and biological variations, ranging from hamartomas to highly malignant, aggressive neoplasms.

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