en biología, a trait or character is a genetically inherited feature of an organism. The term phenotype is sometimes used as a synonym for trait in common use, but strictly speaking, does not indicate the trait, but the status of that trait (p. ej.., the trait eye colour has the phenotypes blue, brown and hazel). Contenido 1 Definición 2 Environmental origin 3 Genetic origin of traits in diploid organisms 4 Mendelian expression of genes in diploid organisms 5 Biochemistry of dominance and extensions to expression of traits 6 Ver también 7 References & Bibliography 8 Textos clave 8.1 Libros 8.2 Papeles 9 Material adicional 9.1 Libros 9.2 Papeles 10 External links Definition A trait may be any single feature or quantifiable measurement of an organism. Sin embargo, the most useful traits for genetic analysis are present in different forms in different individuals. A visible trait is the final product of many molecular and biochemical processes. En la mayoría de los casos, information starts with DNA traveling to RNA and finally to protein (ultimately affecting organism structure and function). This is the Central Dogma of molecular biology as stated by Francis Crick. This information flow may also be followed through the Cell as it travels from the DNA in the Nucleus, to the Cytoplasm, to the Ribosomes and the Endoplasmic Reticulum, and finally to the Golgi Apparatus, which may package the final products for export outside the cell. Cell products are released into the tissue, and organs of an organism, to finally affect the physiology in a way that produces a trait. Environmental origin The environment plays a large role in the determination of traits. This is natural as all organisms must have input (and output) of energy and matter in order to maintain their overall elevated energy state. Genetic origin of traits in diploid organisms The heritable unit that may produce a trait is called a gene. A gene is a strand of DNA that is part of a very long and compacted string of DNA called a chromosome. An important reference point along this string is the centromere; the distance from a gene to the centromere is referred to as the gene's locus or map location. A chromosomal region known to control a trait while the responsible gene within not being identified is referred to as a quantitative trait locus. The nucleus of a diploid cell contains two of each chromosome, with homologous (mostly identical) pairs of chromosomes having the same genes at the same loci. Mendelian expression of genes in diploid organisms A gene is only a DNA code sequence; the slightly different variations of that sequence are called alleles. Alleles can be significantly different and produce different product RNAs. Combinations of different alleles thus go on to generate different traits through the information flow charted above. Por ejemplo, if the alleles on homologous chromosomes exhibit a "simple dominance" relación, the trait of the "dominante" allele shows in the phenotype. Gregor Mendel pioneered modern genetics. His most famous analyses were based on clear-cut traits with simple dominance. He determined that the heritable units, he called "genes", occurred in pairs and could exhibit linkage. His tool was statistics: long before the molecular model of DNA was introduced by James D. Watson and Francis Crick. Biochemistry of dominance and extensions to expression of traits The biochemistry of the intermediate proteins determines how they interact in the cell. Por lo tanto, biochemistry predicts how combinations of different alleles will produce varying traits. Extended expression patterns seen in diploid organisms include facets of incomplete dominance, codominance, and multiple alleles. See also genetics skill genetic linkage edit The development of phenotype Key concepts: Genotype-phenotype distinction | Norms of reaction | Gene-environment interaction | Heritability | Quantitative genetics Genetic architecture: Dominance relationship | Epistasis | Polygenic inheritance | Pleiotropy | Plasticity | Canalisation | Fitness landscape Non-genetic influences: Epigenetic inheritance | Epigenetics | Maternal effect | dual inheritance theory Developmental architecture: Segmentation | Modularity Evolution of genetic systems: Evolvability | Mutational robustness | Evolution of sex Influential figures: C. H. Waddington | Richard Lewontin Debates: Nature versus nurture List of evolutionary biology topics References & Bibliography Key texts Books Papers Additional material Books Papers External links This page uses Creative Commons Licensed content from Wikipedia (ver autores).
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