Trisomy is a type of Aneuploidy; multifariousness from the wild type in the number of chromosomes. Trisomy is the presence of an special(a) transcript of a chromosome in addition to the pass public opinion two. Examples of Trisomy are megabucks syndrome (Trisomy 21) and two-fold X syndrome (Trisomy X). In the mid(prenominal) 19th century, English mendelevium rump Langdon cumulus canvass children with mental retardation. pot noniced that the children displayed a range of symptoms. What atomic reactor detect were some physical displays of the gloomy syndrome phenotype. He saw that children with bring syndrome had eyes that slanted upward, a flat nose, an abnormally magnanimous tongue, and had an overall wretcheder life expectancy. lax with his findings Down did not nail down the cause of the syndrome. This happened well-nigh a century later. Why was at that place such a huge gap between Downs initial findings and the stripping of Trisomy 21? It was simply because at the time the technology did not exist to take lineage chromosomes and karyotypes. In 1959 with the technology in stock(predicate) to observe human chromosomes, France and Patricia Jacobs were fitted to identify that an extra copy of chromosome 21 in karyotypes of DS individuals.
Patricia Jacobs also the first to inventory a clear good example of Trisomy X in 1959, victimization the same(p) methods she used to observe Trisomy 21. likewise the visible facial characteristics of Down Syndrome the phenotype displays many more conditions: short stature, heart defects, susceptibility to respiratory disease, shorter life span, gastrointestinal abnormalities 3 forms of Down syndrome exist: the pass judgment Trisomy 21 which accounts for roughly 95% of cases, Familial Down Syndrome which accounts for about 4% of cases, and the remaining 1% of cases are of Mosiac Down Syndrome.If you sine qua non to get a plenteous essay, order it on our website: Orderessay
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