Genetics Of A Chromosome Is Down Syndrome Essay examples

1457 Words Nov 17th, 2015 6 Pages
Genetics To Down Syndrome
Genetics describes the makeup of our cells, genes, chromosomes, and phenotypes. When there is alter in a gene or a duplication of a chromosome, it can lead to a certain diseases. One of the main diseases known today from a duplication of a chromosome is Down syndrome. John Down first put a name to Down syndrome in 1866, but artifacts from Mexico and Saxon documented some cases of Down syndrome in individuals, and also some were found in paintings of the Renaissance in Europe. (Fisher & Hernandez, 1996) Not till 1959 though did we learn that Trisomy 21 was the known cause of Down syndrome with the presence of 3 copies of chromosome 21. (Bléhaut et all, 2007)1 in every 600 individuals born in the Unites States are diagnosed with Down syndrome making this the most common known genetic cause of mental retardation. (Hassold & Sherman, 2000)
In the human genome, there are 23,000 genes that have to be expressed in certain cells at a precise time. Gene expression happens when cell’s DNA wraps around cluster of a globular histone proteins to form nucleosomes. Nucleosomes and histone are put together to make chromatin. When the structure of chromatin changes, it affects gene expression. This leads to epigenetics patterns of DNA methylation and histone modifications. Alternations of these patterns cause change in the regulation of gene expression. After these changes in gene expression, the results are an epigenetic cause of disease because of the loss of…

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