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26-408: German zoologists Oscar and Richard Hertwig made some of the first discoveries on animal zygote formation in the late 19th century. The zygote is the earliest developmental stage. In humans and most other anisogamous organisms, a zygote is formed when an egg cell and sperm cell come together to create a new unique organism. The formation of a totipotent zygote with the potential to produce

52-539: A Mesolithic settlement have been found in Bruchenbrücken, a suburb of Friedberg. Castle Hill was the location of a Roman military camp , part of the limes or border fortifications and presumably identical with the castellum in monte tauno that is quoted in Roman records during the 1st century AD, though this is still under discussion. Ruins of the camp, as well as other Roman ruins, have been found and conserved, such as

78-583: A Refutation of Darwin's Theory of Chance"). Hertwig was elected a member of the Royal Swedish Academy of Sciences in 1903. Hertwig is known as Oscar Hedwig in the book "Who discovered what when" by David Ellyard. A history of the discovery of fertilization for mammals including scientists like Hertwig and other workers is given by the book "The Mammalian Egg" by Austin. Friedberg, Hesse Friedberg ( German pronunciation: [ˈfʁiːtˌbɛʁk] ; official name: Friedberg (Hessen) )

104-474: A professor of zoology in Munich from 1885 to 1925, at Ludwig Maximilian University , where he served the last 40 years of his 50-year career as a professor at 4 universities. Hertwig was a leader in the field of comparative and causal animal-developmental history. He also wrote a leading textbook. By studying sea urchins he proved that fertilization occurs due to the fusion of a sperm and egg cell. He recognized

130-423: A released ovum (a haploid secondary oocyte with replicate chromosome copies) and a haploid sperm cell ( male gamete) combine to form a single diploid cell called the zygote. Once the single sperm fuses with the oocyte, the latter completes the division of the second meiosis forming a haploid daughter with only 23 chromosomes, almost all of the cytoplasm, and the male pronucleus . The other product of meiosis

156-476: A whole organism depends on epigenetic reprogramming. DNA demethylation of the paternal genome in the zygote appears to be an important part of epigenetic reprogramming. In the paternal genome of the mouse, demethylation of DNA, particularly at sites of methylated cytosines, is likely a key process in establishing totipotency. Demethylation involves the processes of base excision repair and possibly other DNA-repair–based mechanisms. In human fertilization ,

182-809: Is a town and the capital of the Wetteraukreis district, in Hesse , Germany . It is located 26 km (16 miles) north of Frankfurt am Main . In 1966, the town hosted the sixth Hessentag state festival, in 1979 the 19th. The town consists of 7 districts: The old city was refounded by the Hohenstaufen dynasty of the Holy Roman Empire , conveniently located at important trading routes. The city initially rivaled Frankfurt am Main economically, with an important annual trading fair, and initial rapid expansion, though its economic fortunes soon dwindled. City tranquility

208-511: Is further known for being the first duty station of former US Secretary of State and retired four-star General Colin Powell , who was stationed there as a Second Lieutenant in 1958. Friedberg's main station is on the Main-Weser Railway and is the northern terminal of Frankfurt's S-Bahn line S6 and also a stop for German Intercity trains and several regional railway lines. Friedberg

234-520: Is in the main shopping center of the town. Presley's battalion, redesignated the 4th Battalion, 67th Armor, "Bandits," would be later commanded back-to-back by West Point classmates and future Army Generals Albert Bryant, Jr. and Martin Dempsey (the former Chairman of the Joint Chiefs of Staff), who maintained their office above the "Elvis Aaron Presley Mess Hall," originally funded by Presley. Ray Barracks

260-539: Is inherited uniparentally from the mt+ mating type parent. These rare biparental zygotes allowed mapping of chloroplast genes by recombination. Oscar Hertwig Oscar Hertwig (21 April 1849 in Friedberg – 25 October 1922 in Berlin ) was a German embryologist and zoologist known for his research in developmental biology and evolution . Hertwig is credited as the first man to observe sexual reproduction by looking at

286-452: Is the second polar body with only chromosomes but no ability to replicate or survive. In the fertilized daughter, DNA is then replicated in the two separate pronuclei derived from the sperm and ovum, making the zygote's chromosome number temporarily 4n diploid . After approximately 30 hours from the time of fertilization, a fusion of the pronuclei and immediate mitotic division produce two 2n diploid daughter cells called blastomeres . Between

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312-717: Is the substance responsible not only for fertilization but also for the transmission of hereditary characteristics. This early suggestion was proven correct much later in 1944 by the Avery–MacLeod–McCarty experiment which showed that this is indeed the role of the nucleic acid DNA . While Hertwig was interested in developmental biology and evolution, he was opposed to chance as assumed in Charles Darwin ´s theory. His most important theoretical book was: "Das Werden der Organismen, eine Widerlegung der Darwinschen Zufallslehre" (Jena, 1916) (translation: "The Origin of Organisms –

338-507: The United States before the Holocaust, but all remaining Jews were deported in 1942 to Treblinka . The Judenbad (Jewish bath) contains a memorial to the fallen Jewish soldiers who fought for their fatherland during World War I. Today, only the medieval Jewish ceremonial bath, old synagogue arson memorial, and memorial plaque at one of the city's secondary schools are reminders of this part of

364-533: The cells of sea urchins under the microscope. Hertwig was the elder brother of zoologist-professor Richard Hertwig (1850–1937). The Hertwig brothers were the most eminent scholars of Ernst Haeckel (and Carl Gegenbaur ) from the University of Jena . They were independent of Haeckel's philosophical speculations but took his ideas in a positive way to widen their concepts in zoology . Initially, between 1879 and 1883, they performed embryological studies, especially on

390-517: The city's past. Sir Ernest Oppenheimer , diamond mining entrepreneur and former owner of De Beers was born and raised in Friedberg. Friedberg was the home to the U.S. Army installation Ray Barracks . From approximately 1956 to 2007, Ray Barracks was the home of 3rd Brigade 3rd Armored Division. Elvis Presley served in 1st Bn 32nd Armor, whose motor pool and tanks were used in filming Presley's "GI Blues" (1960). The 1st Brigade 1st Armored Division

416-543: The community, maintaining the buildings and governing the affairs of the city. The Friedberg 'noble republic' was unusual in that it was sustained by a large number of families and its organization was formalized by a constitution. Under Napoleon, it was incorporated in the Grand Duchy of Hesse (Hesse-Darmstadt). Friedberg sits atop a basalt plateau overlooking the Usa and has been populated at least since Roman times. The relics of

442-437: The conceptus travels down the fallopian tube towards the uterus while continuing to divide without actually increasing in size, in a process called cleavage . After four divisions, the conceptus consists of 16 blastomeres, and it is known as the morula . Through the processes of compaction, cell division, and blastulation, the conceptus takes the form of the blastocyst by the fifth day of development, just as it approaches

468-589: The politics of Guelf and Ghibelline parties. The city became a Free Imperial City ( Freie Reichsstadt ) of the Holy Roman Empire with a charter given in 1211. From the 14th-15th centuries, a 'noble republic' existed where twelve noble families shared a single castle. Between 1337 and 1498, the constitution for the castle developed with a network of knightly families with rights to elect a Burggraf (burgrave), two Baumeister , and twelve Regimentsburgmannen . They carried out numerous functions such as representing

494-595: The remains of Roman public baths ( thermae ). The Roman settlement was abandoned during the retreat of the Romans on the Rhine frontier by 260 AD. The crown and ports atop the Adolfsturm (the most prominent feature of the Friedberg castle) was restored during the 1980s. Friedberg's old town quarter once housed a prosperous Jewish community that was totally wiped out during World War II . Many of Friedberg's Jews fled to Palestine and

520-471: The role of the cell nucleus during inheritance and chromosome reduction during meiosis : in 1876, he published his findings that fertilization includes the penetration of a spermatozoon into an egg cell. Hermann Fol also observed this in the same year. Hertwig's experiments with frog eggs revealed the 'long axis rule', or Hertwig rule . According to this rule, cell divides along its long axis. In 1885 Hertwig wrote that nuclein (later called nucleic acid )

546-408: The site of implantation. When the blastocyst hatches from the zona pellucida , it can implant in the endometrial lining of the uterus and begin the gastrulation stage of embryonic development. The human zygote has been genetically edited in experiments designed to cure inherited diseases. In fungi, this cell may then enter meiosis or mitosis depending on the life cycle of the species. In plants,

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572-530: The stages of fertilization and implantation , the developing embryo is sometimes termed as a preimplantation- conceptus . This stage has also been referred to as the pre-embryo in legal discourses including relevance to the use of embryonic stem cells. In the US the National Institutes of Health has determined that the traditional classification of pre-implantation embryo is still correct. After fertilization,

598-443: The theory of the coelom (1881), the fluid-filled body cavity. These problems were based on the phylogenetic theorems of Haeckel, i.e. the biogenic theory (German = biogenetisches Grundgesetz), and the " gastraea theory ". Within 10 years, the two brothers moved apart to the north and south of Germany . Oscar Hertwig later became a professor of anatomy in 1888 in Berlin ; however, Richard Hertwig had moved 3 years prior, becoming

624-581: The zygote may be polyploid if fertilization occurs between meiotically unreduced gametes. In land plants , the zygote is formed within a chamber called the archegonium . In seedless plants, the archegonium is usually flask-shaped, with a long hollow neck through which the sperm cell enters. As the zygote divides and grows, it does so inside the archegonium. The zygote can divide asexually by mitosis to produce identical offspring. A Chlamydomonas zygote contains chloroplast DNA (cpDNA) from both parents; such cells are generally rare, since normally cpDNA

650-429: Was hampered by continuous rivalry between the two entities that made up Friedberg: The city and the castle of Friedberg that were politically independent from each other and in permanent competition, often quite maliciously, resulting in bitter rivalry that culminated once in the ransacking and destruction of the castle by angry citizens. In central Italy and Lombardy similar struggles between count and commune fueled

676-568: Was located here as well as in Gießen , Germany. The 1st Brigade (otherwise known as Ready First) was located at Ray Barracks from 1992 to 2007 when the installation was closed permanently and was returned to the city of Friedberg. The base is notable as the duty station of Elvis Presley during his military stint in Europe, who lived in nearby Bad Nauheim . Elvis Presley Platz was named for the American star and

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