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During meiosis homologous chromosomes are separated and only one copy of each chromosome goes into the gamete. If they aren't separated correctly, both copies may go into the gamete. After fertilisation, the embryo will contain 3 copies of that chromosome. If this occurs with chromosome 21, it will result in Down Syndrome.
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∙ 15y ago
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∙ 13y agoNormally, at the time of conception a baby inherits genetic information from its parents in the form of 46 chromosomes: 23 from the mother and 23 from the father. In most cases of Down syndrome, a child gets an extra chromosome 21 - for a total of 47 chromosomes instead of 46. It's this extra genetic material that causes the physical features and developmental delays associated with DS.
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∙ 14y agoDown syndrome is a result of a genetic abnormality that is present from the stage of a single fertilized egg. Specifically, it is when the embryo has three copies of chromosome #21 instead of the normal two copies. It is therefore also known as trisomy 21.
This being said, you cannot "get" down syndrome - you are either born with it or without it.
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∙ 13y agoChromosome 21.
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∙ 12y agoYes
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Down syndrome is usually caused by an extra copy of what chromosome?
Down syndrome occurs because of the extra chromosome on chromosome 21. If you go onto google images and type in karyotype of Down syndrome, you will find a picture of the extra chromosome. Instead of having two chromosomes on chromosome 21, there is an extra. Type your answer here...
What genectic disorder does Down syndrome involve?
Down Syndrome is when there is an extra chromosome in someones DNA. More exactly it is when the 21st chromosome has an extra one.
What chromosomes do you get an extra copy for in humans that results in Down syndrome?
Down Syndrome is caused by a triplication of the 21st chromosome.
People with down syndrome have how many chromosomes?
47There are 47 chromosomes in someone with Down syndrome; the 21st pair has an extra chromosome. Most people have 46 chromosomes. Down syndrome is also known as "Trisomy 21" - a reference to the fact that someone with Down syndrome has 3 pairs of chromosomes on their 21st pair.
Who has down syndrome?
Anyone with an extra chromosome 21.
What does it mean when someone has an extra chromosome?
If someone has an extra chromosome it means there was a genetic mutation that is abnormal in human development. It may result in problems with the person affecting them on a basic level, or may go fully unnoticed. A common disorder that can be caused by having an extra chromosome is Down's Syndrome.
Does Down syndrome occur in a specific location?
Down Syndrome is known as trisomy 21 because someone with the syndrome has 3 chromosomes of the same type when we are only supposed to have 2 (one from each parent). Chromosomes are paired and numbered so Down Syndrome is the result of having 3 of the #21 chromosome. The body will not know what to do with the extra chromosome so as a precautionary measure it will shut down all 3 and the genes that are within the chromosomes can no longer be accessed. So as you can see, Down Syndrome is not from being inherited by a specific gene. It is due to an error in meiosis in either the mother or the father.
Is down syndrome a mutation?
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.
What are the causes of heredity diseases?
The causes of a hereditary disease is a missing chromosome, and extra chromosome. Like in Down Syndrome there is an extra chromosome 26.
Is Angelman syndrome the same as Down syndrome?
Angelman syndrome is a genetic disorder, as is Down syndrome. But they are not the same. Angelman Syndrome involves a deletion of Chromosome 15, whereas people with Down syndrome have an extra copy of Chromosome 21.
What condition results when a child is born with an extra chromosome on the third pair?
Down syndrome
Is Down syndrome a genetic disorder or a chromosome disorder?
Down syndrome is a chromosomal disorder. It is caused by having 1 extra chromosome (chromosome 21).
