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Disorders, such as Down's Syndrome, are caused by nondisjunction.
Nondisjunction
Nondisjunction.
Its called disconjunction. Sometimes it is so bad that they have a miscarriage or the following happens:Trisomy (extra chromosomeso have 47 chromosomes instead of 46)Down's syndrome (andextra number 21 chromosome)Klinefelter's syndrome (males with an extra X chromosome...XXY)
Nondisjunction
Down's Syndrome
Nondisjunction is the medical term meaning abnormal condition of meiosis. For example, trisomy 21 (Down syndrome) is a nondisjunction.
Nondisjunction is the failure of a homolog to separate during meiosis causing trisomy (an extra chromosome) or monosomy (a missing chromosome), it can be harmful because it is a mutation that can cause many devastating disease, for example nondisjunction of the 21st chromosome causes down syndrome, another example of nondisjunction being harmful, is nondisjunction of the sex chromosomes, causing Turner's or Klinefelter's syndrome two very devastating diseases.
kleinfelters syndrome
It's more sever in meiotic nondisjunction, since this is the most common way that trisomy 21 (Down syndrome) arises. mitotic nondisjunction is less sever because it means that some cells will be mosaic, meaning they could be normal while some with have the (2n+1) while other cell will be (2n). So, in mitotic nondisjunction it depend how many cells are carrying the extra 21 chromosome. In end of the day they can't be worse than Down syndrome that rose from meiotic nondisjucntion since it has the highest amount of cells carrying trisomy 21.. I hope this helps
Down Syndrome is caused by extra genetic material on Chromosome 21. About half of the children of people who have Down Syndrome are born with Down Syndrome themselves. See the Related Linksbelow to view an article about the genetics of Down Syndrome.
Causes of Klinefelter SyndromeThe additional sex chromosomes in men with Klinefelter syndrome results from nondisjunction during meiosis and may have a paternal (50 to 60 percent) or maternal (40 to 50 percent) origin. This contrasts with Down syndrome, which is caused predominantly by maternal nondisjunction and inheritance of the extra chromosome 21 from the mother.