Tài liệu, ebook Khoa Học Tự Nhiên

Phenotype may not be obvious in the progeny, but still instructive Other cases can be lethal with the mice dying before birth Intermediate effects are also common and may require monitoring during the life of the mouse

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Bacterium infects plant, transfers Ti plasmid to host cells T-DNA integrates into the plant DNA causing abnormal proliferation of plant cells T-DNA genes direct the synthesis of unusual organic acids, opines which can serve as an energy source to the infecting bacteria but are useless to the plant

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Sickle cell disease is a genetic disorder The disease results from a single base change in the gene for b-globin Altered base causes insertion an incorrect amino acid into one position of the b-globin protein Altered protein results in distortion of red blood cells under low-oxygen conditions This disease illustrates that a change in a gene can...

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There is a rough correlation between DNA content and number of genes in a cell or virus This correlation breaks down in several cases of closely related organisms where the DNA content per haploid cell (C-value) varies widely C-value paradox is probably explained not by extra genes, but by extra noncoding DNA in some organisms

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Current research theories support the division of living organisms into three domains Bacteria Eukaryota Archaea living in the most inhospitable regions of the earth Thermophiles tolerate extremely high temperatures Halophiles tolerate very high salt concentrations Methanogens produce methane as a by-product of metabolism

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Prediction Individual genome sequence can be used to determine chance of developing a particular disease Blood fingerprints will allow early detection and stratification of disease types New prevention strategies Better understanding of networks will lead to more effective therapeutic agents and drugs to prevent disease Personalization Apply ...

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Evolutionary battle at the molecular level between the AIDS virus and cells of the immune system After viral infection, virus-specific immune response ensues that can destroy the pathogen HIV has a high mutation rate and is able to diversity and amplify itself via selection Speed of viral evolution is faster than the immune response Effective t...

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Heritability quantifies the potential for selection A trait with high heritability has a large potential for evolution Selection differential = S Difference between value for this trait in the parents and value for this trait in the entire population (breeding and non-breeding) Response to selection = R The amount of change in the mean value ...

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Cells must obtain information about their positions relative to other cells Ligand expressed by one cell binds to a receptor expressed on the surface of another cell Juxtracrine signaling – ligand is membrane-bound and interacts with a receptor on an adjacent cell Paracrine signaling – ligand is secreted and mediates long- range (e.g. hormones) ...

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Cancer is a disease of genes Multiple cancer phenotypes arise from mutations in genes that regulate cell growth and division Environmental chemicals increase mutation rates and increase chances of cancer Cancer has a different inheritance pattern than other genetic disorders Inherited mutations can predispose to cancer, but the mutations causin...

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