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Phenotypic Switching
In genetics, the phenotype () is the set of observable characteristics or traits of an organism. The term covers the organism's morphology (physical form and structure), its developmental processes, its biochemical and physiological properties, and its behavior. An organism's phenotype results from two basic factors: the expression of an organism's genetic code (its genotype) and the influence of environmental factors. Both factors may interact, further affecting the 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 again in his 1982 book '' The Extended Phenotype'' suggested that one can regard bird nests and other built structures such as caddisfly larva cases and beaver dams as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coquina Variation3
Coquina () is a sedimentary rock that is composed either wholly or almost entirely of the transported, abraded, and mechanically sorted fragments of mollusks, trilobites, brachiopods, or other invertebrates. The term ''coquina'' comes from the Spanish language, Spanish word for "cockle (bivalve), cockle" and "shellfish". For a sediment to be considered to be a coquina, the particles composing it should average or greater in size. Coquina can vary in hardness from poorly to moderately cementation (geology), cemented. Incompletely consolidated and poorly cemented coquinas are considered grainstones in the Dunham classification system for carbonate sedimentary rocks. A well-cemented coquina is classified as a biosparite (fossiliferous limestone) according to the Folk classification, Folk classification of sedimentary rocks. Coquinas accumulate in high-energy marine and Lacustrine deposits, lacustrine environments where currents and waves result in the vigorous winnowing, abrasion, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilhelm Johannsen
Wilhelm Johannsen (3 February 1857 – 11 November 1927) was a Danish pharmacist, botanist, plant physiologist, and geneticist. He is best known for coining the terms gene, phenotype and genotype, and for his 1903 "pure line" experiments in genetics. Biography Johannsen was born in Copenhagen. While very young, he was apprenticed to a pharmacist and worked in Denmark and Germany beginning in 1872 until passing his pharmacist's exam in 1879. In 1881, he became assistant in the chemistry department at the Carlsberg Laboratory under the chemist Johan Kjeldahl. Johannsen studied the metabolism of dormancy and germination in seeds, tubers and buds. He showed that dormancy could be broken by various anesthetic compounds, such as diethyl ether and chloroform. In 1892, he was appointed lecturer at Royal Veterinary and Agricultural University and later became professor of botany and plant physiology. He taught plant physiology. His best-known research concerned so-called ''pure ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cell (biology)
The cell is the basic structural and functional unit of all life, forms of life. Every cell consists of cytoplasm enclosed within a Cell membrane, membrane; many cells contain organelles, each with a specific function. The term comes from the Latin word meaning 'small room'. Most cells are only visible under a light microscope, microscope. Cells Abiogenesis, emerged on Earth about 4 billion years ago. All cells are capable of Self-replication, replication, protein synthesis, and cell motility, motility. Cells are broadly categorized into two types: eukaryotic cells, which possess a Cell nucleus, nucleus, and prokaryotic, prokaryotic cells, which lack a nucleus but have a nucleoid region. Prokaryotes are single-celled organisms such as bacteria, whereas eukaryotes can be either single-celled, such as amoebae, or multicellular organism, multicellular, such as some algae, plants, animals, and fungi. Eukaryotic cells contain organelles including Mitochondrion, mitochondria, which ... [...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 regarded 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] |
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 (red blood cells). For human blood transfusions, it is the most important of the 47 different blood type (or group) classification systems currently recognized by the International Society of Blood Transfusions (ISBT) as of December 2022. A mismatch in this serotype (or in various others) can cause a potentially fatal adverse reaction after a transfusion, or an unwanted immune response to an organ transplant. Such mismatches are rare in modern medicine. 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, mon ... [...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; 47 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] |
Protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metabolic reactions, DNA replication, Cell signaling, responding to stimuli, providing Cytoskeleton, structure to cells and Fibrous protein, organisms, and Intracellular transport, transporting molecules from one location to another. Proteins differ from one another primarily in their sequence of amino acids, which is dictated by the Nucleic acid sequence, nucleotide sequence of their genes, and which usually results in protein folding into a specific Protein structure, 3D structure that determines its activity. A linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide. Short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molecule
A molecule is a group of two or more atoms that are held together by Force, attractive forces known as chemical bonds; depending on context, the term may or may not include ions that satisfy this criterion. In quantum physics, organic chemistry, and biochemistry, the distinction from ions is dropped and ''molecule'' is often used when referring to polyatomic ions. A molecule may be homonuclear, that is, it consists of atoms of one chemical element, e.g. two atoms in the oxygen molecule (O2); or it may be heteronuclear, a chemical compound composed of more than one element, e.g. water (molecule), water (two hydrogen atoms and one oxygen atom; H2O). In the kinetic theory of gases, the term ''molecule'' is often used for any gaseous particle regardless of its composition. This relaxes the requirement that a molecule contains two or more atoms, since the noble gases are individual atoms. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Selfish Gene
''The Selfish Gene'' is a 1976 book on evolution by ethologist Richard Dawkins that promotes the gene-centred view of evolution, as opposed to views focused on the organism and the group. The book builds upon the thesis of George C. Williams's '' Adaptation and Natural Selection'' (1966); it also popularized 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 gene, suggesting that such "selfish" replication may also model human cult ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatic Cell
In cellular biology, a somatic cell (), or vegetal cell, is any biological cell forming the body of a multicellular organism other than a gamete, germ cell, gametocyte or undifferentiated stem cell. Somatic cells compose the body of an organism and divide through mitosis. In contrast, gametes derive from meiosis within the germ cells of the germline and they fuse during sexual reproduction. Stem cells also can divide through mitosis, but are different from somatic in that they differentiate into diverse specialized cell types. In mammals, somatic cells make up all the internal organs, skin, bones, blood and connective tissue, while mammalian germ cells give rise to spermatozoa and ova which fuse during fertilization to produce a cell called a zygote, which divides and differentiates into the cells of an embryo. There are approximately 220 types of somatic cell in the human body. Theoretically, these cells are not germ cells (the source of gametes); they transmit their mut ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Germ Plasm
Germ plasm () is a biological concept developed in the 19th century by the German biologist August Weismann. It states that heritable information is transmitted only by germ cells in the gonads (ovaries and testes), not by somatic cells. The related idea that information cannot pass from somatic cells to the germ line, contrary to Lamarckism, is called the Weismann barrier. To some extent this theory anticipated the development of modern genetics. History The term ''Keimplasma'' (germ plasm) was first used by the German biologist, August Weismann (1834–1914), and described in his 1892 book ''Das Keimplasma: eine Theorie der Vererbung'' (The Germ Plasm: a theory of inheritance). His theory states that multicellular organisms consist of germ cells that contain and transmit heritable information, and somatic cells which carry out ordinary bodily functions. In the germ plasm theory, inheritance in a multicellular organism only takes place by means of the germ cells: the gamete ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
