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Phenotype
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology or physical form and structure, its developmental processes, its biochemical and physiological properties, its behavior, and the products of behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code, or its genotype, and the influence of environmental factors. Both factors may interact, further affecting phenotype. When two or more clearly different phenotypes exist in the same population of a species, the species is called polymorphic. A well-documented example of polymorphism is Labrador Retriever coloring; while the coat color depends on many genes, it is clearly seen in the environment as yellow, black, and brown. Richard Dawkins in 1978 and then again in his 1982 book '' The Extended Phenotype'' suggested that one can regard bird nests and other built structures such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Extended Phenotype
''The Extended Phenotype'' is a 1982 book by the evolutionary biologist Richard Dawkins, in which the author introduced a biological concept of the same name. The main idea is that phenotype should not be ''limited'' to biological processes such as protein biosynthesis or tissue growth, but ''extended'' to include all effects that a gene has on its environment, inside or outside the body of the individual organism. Dawkins considers ''The Extended Phenotype'' to be a sequel to ''The Selfish Gene'' (1976) aimed at professional biologists, and as his principal contribution to evolutionary theory. Summary Genes as the unit of selection in evolution The central thesis of ''The Extended Phenotype,'' and of its predecessor by the same author ''The'' ''Selfish Gene'', is that individual organisms are not the true units of natural selection. Instead, the gene — or the ‘active, germ-line replicator’ — is the unit upon which the forces of evolutionary selection and adaptation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Richard Dawkins
Richard Dawkins (born 26 March 1941) is a British evolutionary biologist and author. He is an emeritus fellow of New College, Oxford and was Professor for Public Understanding of Science in the University of Oxford from 1995 to 2008. An atheist, he is well known for his criticism of creationism and intelligent design. Dawkins first came to prominence with his 1976 book '' The Selfish Gene'', which popularised the gene-centred view of evolution and introduced the term '' meme''. With his book '' The Extended Phenotype'' (1982), he introduced into evolutionary biology the influential concept that the phenotypic effects of a gene are not necessarily limited to an organism's body, but can stretch far into the environment, for example, when a beaver builds a dam. His 2004 The Ancestor's Tale set out to make understanding evolution simple for the general public, by tracing common ancestors back from humans to the origins of life. Over time, numerous religious people challen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genotype
The genotype of an organism is its complete set of genetic material. Genotype can also be used to refer to the alleles or variants an individual carries in a particular gene or genetic location. The number of alleles an individual can have in a specific gene depends on the number of copies of each chromosome found in that species, also referred to as ploidy. In diploid species like humans, two full sets of chromosomes are present, meaning each individual has two alleles for any given gene. If both alleles are the same, the genotype is referred to as Zygosity, homozygous. If the alleles are different, the genotype is referred to as heterozygous. Genotype contributes to phenotype, the observable traits and characteristics in an individual or organism. The degree to which genotype affects phenotype depends on the trait. For example, the petal color in a pea plant is exclusively determined by genotype. The petals can be purple or white depending on the alleles present in the pea plan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Selfish Gene
''The Selfish Gene'' is a 1976 book on evolution by the ethologist Richard Dawkins, in which the author builds upon the principal theory of George C. Williams's '' Adaptation and Natural Selection'' (1966). Dawkins uses the term "selfish gene" as a way of expressing the gene-centred view of evolution (as opposed to the views focused on the organism and the group), popularising ideas developed during the 1960s by W. D. Hamilton and others. From the gene-centred view, it follows that the more two individuals are genetically related, the more sense (at the level of the genes) it makes for them to behave cooperatively with each other. A lineage is expected to evolve to maximise its inclusive fitness—the number of copies of its genes passed on globally (rather than by a particular individual). As a result, populations will tend towards an evolutionarily stable strategy. The book also introduces the term '' meme'' for a unit of human cultural evolution analogous to the gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genotype–phenotype Distinction
The genotype–phenotype distinction is drawn in genetics. "Genotype" is an organism's full hereditary information. "Phenotype" is an organism's actual observed properties, such as morphology, development, or behavior. This distinction is fundamental in the study of inheritance of traits and their evolution. Overview The terms "genotype" and "phenotype" were created by Wilhelm Johannsen in 1911, although the meaning of the terms and the significance of the distinction have evolved since they were introduced. It is the organism's physical properties that directly determine its chances of survival and reproductive output, but the inheritance of physical properties is dependent on the inheritance of genes. Therefore, understanding the theory of evolution via natural selection requires understanding the genotype–phenotype distinction. The genes contribute to a trait, and the phenotype is the observable expression of the genes (and therefore the genotype that affects the trait). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wild Type
The wild type (WT) is the phenotype of the typical form of a species as it occurs in nature. Originally, the wild type was conceptualized as a product of the standard "normal" allele at a locus, in contrast to that produced by a non-standard, "mutant" allele. "Mutant" alleles can vary to a great extent, and even become the wild type if a genetic shift occurs within the population. Continued advancements in genetic mapping technologies have created a better understanding of how mutations occur and interact with other genes to alter phenotype. It is now appreciated that most or all gene loci exist in a variety of allelic forms, which vary in frequency throughout the geographic range of a species, and that a uniform wild type does not exist. In general, however, the most prevalent allele – i.e., the one with the highest gene frequency – is the one deemed wild type. The concept of wild type is useful in some experimental organisms such as fruit flies ''Drosophila melanogaster'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Morphology (biology)
Morphology is a branch of biology dealing with the study of the form and structure of organisms and their specific structural features. This includes aspects of the outward appearance ( shape, structure, colour, pattern, size), i.e. external morphology (or eidonomy), as well as the form and structure of the internal parts like bones and organs, i.e. internal morphology (or anatomy). This is in contrast to physiology, which deals primarily with function. Morphology is a branch of life science dealing with the study of gross structure of an organism or taxon and its component parts. History The etymology of the word "morphology" is from the Ancient Greek (), meaning "form", and (), meaning "word, study, research". While the concept of form in biology, opposed to function, dates back to Aristotle (see Aristotle's biology), the field of morphology was developed by Johann Wolfgang von Goethe (1790) and independently by the German anatomist and physiologist Karl Fr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organism
In biology, an organism () is any life, living system that functions as an individual entity. All organisms are composed of cells (cell theory). Organisms are classified by taxonomy (biology), taxonomy into groups such as Multicellular organism, multicellular animals, plants, and fungi; or Unicellular organism, unicellular microorganisms such as protists, bacteria, and archaea. All types of organisms are capable of reproduction, Developmental biology, growth and development, homeostasis, maintenance, and some degree of response to Stimulus (physiology), stimuli. Beetles, squids, tetrapods, mushrooms, and vascular plants are examples of multicellular organisms that Cellular differentiation, differentiate specialized tissue (biology), tissues and organ (anatomy), organs during developmental biology, development. A unicellular organism may be either a prokaryote or a eukaryote. Prokaryotes are represented by two separate Three-domain system, domains – bacteria and arc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Diversity
Genetic diversity is the total number of Genetics, genetic characteristics in the genetic makeup of a species, it ranges widely from the number of species to differences within species and can be attributed to the span of survival for a species. It is distinguished from ''genetic variability'', which describes the tendency of genetic characteristics to vary. Genetic diversity serves as a way for populations to adapt to changing environments. With more variation, it is more likely that some individuals in a population will possess variations of alleles that are suited for the environment. Those individuals are more likely to survive to produce offspring bearing that allele. The population will continue for more generations because of the success of these individuals. The academic field of population genetics includes several hypotheses and theories regarding genetic diversity. The neutral theory of evolution proposes that diversity is the result of the accumulation of neutral subs ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
ABO Blood Group Phenotypes
The ABO blood group system is used to denote the presence of one, both, or neither of the A and B antigens on erythrocytes. For human blood transfusions, it is the most important of the 43 different blood type (or group) classification systems currently recognized by the International Society of Blood Transfusions (ISBT) as of June 2021. A mismatch (very rare in modern medicine) in this, or any other serotype, can cause a potentially fatal adverse reaction after a transfusion, or an unwanted immune response to an organ transplant. The associated anti-A and anti-B antibodies are usually IgM antibodies, produced in the first years of life by sensitization to environmental substances such as food, bacteria, and viruses. The ABO blood types were discovered by Karl Landsteiner in 1901; he received the Nobel Prize in Physiology or Medicine in 1930 for this discovery. ABO blood types are also present in other primates such as apes and Old World monkeys. History Discovery The ABO bl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Blood Group Systems
The term human blood group systems is defined by the International Society of Blood Transfusion (ISBT) as systems in the human species where cell-surface antigens—in particular, those on blood cells—are "controlled at a single gene locus or by two or more very closely linked homologous genes with little or no observable recombination between them", and include the common ABO and Rh (Rhesus) antigen systems, as well as many others; 43 human systems are identified . Table of systems and classifications Antibodies Following is a comparison of clinically relevant characteristics of antibodies against the main human blood group systems: Compatibility testing Blood compatibility testing is performed before blood transfusion, including matching of the ABO blood group system and the Rh blood group system, as well as screening for recipient antibodies against other human blood group systems. Blood compatibility testing is also routinely performed on pregnant women and on ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Blot
The western blot (sometimes called the protein immunoblot), or western blotting, is a widely used analytical technique in molecular biology and immunogenetics to detect specific proteins in a sample of tissue homogenate or extract. Besides detecting the proteins, this technique is also utilized to visualize, distinguish, and quantify the different proteins in a complicated protein combination. Western blot technique uses three elements to achieve its task of separating a specific protein from a complex: separation by size, transfer of protein to a solid support, and marking target protein using a primary and secondary antibody to visualize. A synthetic or animal-derived antibody (known as the primary antibody) is created that recognizes and binds to a specific target protein. The electrophoresis membrane is washed in a solution containing the primary antibody, before excess antibody is washed off. A secondary antibody is added which recognizes and binds to the primary antibod ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
