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Lilian Vaughan Morgan
Lilian Vaughan Morgan (''née'' Sampson; July 7, 1870 – December 6, 1952) was an American experimental biologist who made seminal contributions to the genetics of the fruit fly, ''Drosophila melanogaster'', which cemented its status as one of the most powerful model systems in biology. In addition to her scientific career, she was involved in science education and was one of the founders of the Children's School of Science in Woods Hole, Massachusetts. Early life Morgan was born in 1870 in Hallowell, Maine. She was orphaned at the age of three when her parents and younger sister died of tuberculosis. After the death of her parents, she and her older sister Edith were raised by her maternal grandparents in Germantown, Pennsylvania. Early research career Morgan enrolled as an undergraduate student at Bryn Mawr in 1887. She majored in biology and was advised by Martha Carey Thomas. After her graduation with honors in 1891, she spent the summer at the Marine Biological Lab ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hallowell, Maine
Hallowell is a city in Kennebec County, Maine, United States. The population was 2,570 at the 2020 census. Popular with tourists, Hallowell is noted for its culture and old architecture. Hallowell is included in the Augusta, Maine, micropolitan New England City and Town Area. History The city is named for Benjamin Hallowell, a Boston merchant and one of the Kennebec Proprietors, holders of land originally granted to the Plymouth Company by the British monarchy in the 1620s. First to settle here was Deacon Pease Clark, who emigrated with his wife and son Peter from Attleborough, Massachusetts, in the spring of 1762. Legend has it that after disembarking on the west side of the Kennebec, near present-day Water Street, the Clarks took shelter in their overturned cart. On a riverfront lot measuring 50 rods (275 yards, about 250 meters), the Clark family raised corn, rye and other crops. The first land they cleared was occupied by the fire department in 1859. In 1797, Harring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Edmund Beecher Wilson
Edmund Beecher Wilson (October 19, 1856 – March 3, 1939) was a pioneering American zoologist and geneticist. He wrote one of the most influential textbooks in modern biology, ''The Cell''. Career Wilson was born in Geneva, Illinois, the son of Isaac G. Wilson, a judge, and his wife, Carioline Clark. He graduated from Yale University in 1878. He earned his Ph.D. at Johns Hopkins in 1881. He was a lecturer at Williams College in 1883–84 and at the Massachusetts Institute of Technology in 1884–85. He served as professor of biology at Bryn Mawr College from 1885 to 1891. In 1888, he was elected as a member to the American Philosophical Society. He spent the balance of his career at Columbia University where he was successively adjunct professor of biology (1891–94), professor of invertebrate zoology (1894–1897), and professor of zoology (from 1897). Wilson is credited as America's first cell biologist. In 1898 he used the similarity in embryos to describe phylogene ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ring Chromosomes
A ring chromosome is an aberrant chromosome whose ends have fused together to form a ring. Ring chromosomes were first discovered by Lilian Vaughan Morgan in 1926. A ring chromosome is denoted by the symbol ''r'' in human genetics and ''R'' in ''Drosophila'' genetics. Ring chromosomes may form in cells following genetic damage by mutagens like radiation, but they may also arise spontaneously during development. Formation In order for a chromosome to form a ring, both ends of the chromosome are usually missing, enabling the broken ends to fuse together. In rare cases, the telomeres at the ends of a chromosome fuse without any loss of genetic material, which results in a normal phenotype. Complex rearrangements, including segmental microdeletions and microduplications, have been seen in numerous ring chromosomes, providing important clues regarding the mechanisms of their formation. [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Genetic Recombination
Genetic recombination (also known as genetic reshuffling) is the exchange of genetic material between different organisms which leads to production of offspring with combinations of traits that differ from those found in either parent. In eukaryotes, genetic recombination during meiosis can lead to a novel set of genetic information that can be further passed on from parents to offspring. Most recombination occurs naturally and can be classified into two types: (1) ''interchromosomal'' recombination, occurring through independent assortment of alleles whose loci are on different but homologous chromosomes (random orientation of pairs of homologous chromosomes in meiosis I); & (2) ''intrachromosomal'' recombination, occurring through crossing over. During meiosis in eukaryotes, genetic recombination involves the pairing of homologous chromosomes. This may be followed by information transfer between the chromosomes. The information transfer may occur without physical exchange (a se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chromosome
A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are the histones. These proteins, aided by chaperone proteins, bind to and condense the DNA molecule to maintain its integrity. These chromosomes display a complex three-dimensional structure, which plays a significant role in transcriptional regulation. Chromosomes are normally visible under a light microscope only during the metaphase of cell division (where all chromosomes are aligned in the center of the cell in their condensed form). Before this happens, each chromosome is duplicated ( S phase), and both copies are joined by a centromere, resulting either in an X-shaped structure (pictured above), if the centromere is located equatorially, or a two-arm structure, if the centromere is located distally. The joined copies are now called si ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Centromere
The centromere links a pair of sister chromatids together during cell division. This constricted region of chromosome connects the sister chromatids, creating a short arm (p) and a long arm (q) on the chromatids. During mitosis, spindle fibers attach to the centromere via the kinetochore. The physical role of the centromere is to act as the site of assembly of the kinetochores – a highly complex multiprotein structure that is responsible for the actual events of chromosome segregation – i.e. binding microtubules and signaling to the cell cycle machinery when all chromosomes have adopted correct attachments to the spindle, so that it is safe for cell division to proceed to completion and for cells to enter anaphase. There are, broadly speaking, two types of centromeres. "Point centromeres" bind to specific proteins that recognize particular DNA sequences with high efficiency. Any piece of DNA with the point centromere DNA sequence on it will typically form a centromere if pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alfred Sturtevant
Alfred Henry Sturtevant (November 21, 1891 – April 5, 1970) was an American geneticist. Sturtevant constructed the first genetic map of a chromosome in 1911. Throughout his career he worked on the organism ''Drosophila melanogaster'' with Thomas Hunt Morgan. By watching the development of flies in which the earliest cell division produced two different genomes, he measured the embryonic distance between organs in a unit which is called the '' sturt'' in his honor. In 1967, Sturtevant received the National Medal of Science. Biography Alfred Henry Sturtevant was born in Jacksonville, Illinois, United States on November 21, 1891, the youngest of Alfred Henry and Harriet Sturtevant's six children. His grandfather Julian Monson Sturtevant, a Yale University graduate, was a founding professor and second president of Illinois College, where his father taught mathematics. When Sturtevant was seven years old, his father quit his teaching job and moved the family to Alabama to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Isabel Morgan
Isabel Merrick Morgan (also Morgan Mountain) (20 August 1911 – 18 August 1996) was an American virologist at Johns Hopkins University, who prepared an experimental vaccine that protected monkeys against polio in a research team with David Bodian and Howard A. Howe. Their research led to the identification of three distinct serotypes of poliovirus, all of which must be incorporated for a vaccine to provide complete immunity from poliomyelitis. Morgan was the first to successfully use a killed-virus for polio inoculation in monkeys. After she married in 1949, she left the field of polio research in part because she was uncomfortable with trials that tested polio vaccines on the nerve tissue of children. She then worked on epidemiological studies on air pollution. Later in life, she was a consultant for studies of cancer therapies at the Sloan-Kettering Cancer Institute. Early life and education Isabel Merrick Morgan was born 20 August 1911, in New Bedford, Massachusetts ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hopkins Marine Station
Hopkins Marine Station is the marine laboratory of Stanford University. It is located ninety miles south of the university's main campus, in Pacific Grove, California (United States) on the Monterey Peninsula, adjacent to the Monterey Bay Aquarium. It is home to ten research laboratories and a fluctuating population of graduate and undergraduate students. It has also been used for archaeological exploration, including of the Chinese-American fishing village that existed on the site before burning down in 1906. History Hopkins Marine Station was founded in 1892, making it the oldest marine laboratory on the US Pacific Coast, and the second-oldest in the US, after the Marine Biological Laboratory in Woods Hole, Massachusetts. It was originally named the Hopkins Seaside Laboratory and located on what is now called Lovers Point. In 1917, the laboratory was moved to its current location on Mussel/China/Cabrillo Point, and given its current name: Hopkins Marine Station of Stanford Un ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Planarian
A planarian is one of the many flatworms of the traditional class Turbellaria. It usually describes free-living flatworms of the order Tricladida (triclads), although this common name is also used for a wide number of free-living platyhelminthes. Planaria are common to many parts of the world, living in both saltwater and freshwater ponds and rivers. Some species are terrestrial and are found under logs, in or on the soil, and on plants in humid areas. The triclads are characterized by triply branched intestine and anteriorly situated ovaries, next to the brain. Today the order Tricladida is split into three suborders, according to their phylogenetic relationships: Maricola, Cavernicola and Continenticola. Formerly, the Tricladida was split according to habitats: Maricola, which is marine; Paludicola which inhabits freshwater; and Terricola, which is land-dwelling. Planaria exhibit an extraordinary ability to regenerate lost body parts. For example, a planarian split lengt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ernst Haeckel
Ernst Heinrich Philipp August Haeckel (; 16 February 1834 – 9 August 1919) was a German zoologist, naturalist, eugenicist, philosopher, physician, professor, marine biologist and artist. He discovered, described and named thousands of new species, mapped a genealogical tree relating all life forms and coined many terms in biology, including ''ecology'', '' phylum'', ''phylogeny'', and ''Protista.'' Haeckel promoted and popularised Charles Darwin's work in Germany and developed the influential but no longer widely held recapitulation theory ("ontogeny recapitulates phylogeny") claiming that an individual organism's biological development, or ontogeny, parallels and summarises its species' evolutionary development, or phylogeny. The published artwork of Haeckel includes over 100 detailed, multi-colour illustrations of animals and sea creatures, collected in his ''Kunstformen der Natur'' ("Art Forms of Nature"), a book which would go on to influence the Art Nouveau artistic mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arnold Lang
Arnold Lang (18 June 1855 – 30 November 1914) was a Swiss naturalist, a comparative anatomist and student of German biologist Ernst Haeckel. Biography In March 1876 he earned his PhD from the University of Jena, and two months later became habilitated as a privat-docent of zoology at the University of Bern. From 1878 to 1885 he was stationed at the Zoological Station in Naples, where he conducted research on wildlife native to the Gulf of Naples. In 1889 he became a professor of zoology and comparative anatomy at the University of Zurich and the '' Eidgenössische Polytechnikum'' as well as director of two institutions' zoological collections. From 1898 to 1900 he served as rector at the University of Zurich.Arnold Lang (1855 up to 1914) at ETH Bibliotek In the autumn o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
