1) down's syndrome2) turner syndrome3) jacob's syndrome
Three copies of chromosomes are known as trisomy. This genetic condition can result in disorders such as Down syndrome (trisomy 21) when an individual has an extra copy of chromosome 21.
The general term is aneuploidy. Some examples: Down Syndrome is a commonly known condition in which the person has an extra copy, making three, of the 21st chromosome. Others are Edwards Syndrome (an extra 18th) and Patau Syndrome (and extra 13th).
In Down syndrome, a person's cells have an extra copy of chromosome 21. In other words, instead of a pair of chromosomes, a person with Down syndrome has three of that chromosome. Down syndrome most often occurs when chromosomes fail to separate properly during meiosis. People with Down syndrome have a degree of mental retardation. Heart defects are also common, but can be treated.
People with Down syndrome, also called mongoloidism have 47 chromosomes. Having 65 chromosomes would be lethal, as normally having 47 chromosomes is lethal. Down syndrome is also known as trisomy 21, because instead of two copies of chromosome 21, a person with Down syndrome has three copies, which accounts for the 47th chromosome.
The condition in which an organism has complete extra sets of chromosomes is called polyploidy. This condition can cause a number of severe birth defects. Most do not live a full lifespan for their species.
Trisomy means having three copies of a chromosomes. Turner's syndrome is NOT an example of trisomy. Someone with Turner's syndrome has only one X chromosome. Down's syndrome IS an example of trisomy. Someone with Down's syndrome has 3 copies of chromosome 21. Klinefelter's syndrome is a tricky one. On one hand, it would be considered trisomy because they have 3 sex chromosomes. However, they are not all the SAME sex chromosomes. Someone with Klinefelter's has 2 X chromosomes and one Y chromosome.
In Down syndrome, a person's cells have an extra copy of chromosome 21. In other words, instead of a pair of chromosomes, a person with down syndrome has three of that chromosome. Down syndrome most often occurs when chromosomes fail to separate properly during meiosis. People with down syndrome have a degree of mental retardation. Heart defects are also common, but can be treated.
down syndrome
In Down syndrome, a person's cells have an extra copy of chromosome 21. In other words, instead of a pair of chromosomes, a person with down syndrome has three of that chromosome. Down syndrome most often occurs when chromosomes fail to separate properly during meiosis. People with down syndrome have a degree of mental retardation. Heart defects are also common, but can be treated.
In Down syndrome, a person's cells have an extra copy of chromosome 21. In other words, instead of a pair of chromosomes, a person with Down syndrome has three of that chromosome. Down syndrome most often occurs when chromosomes fail to separate properly during meiosis. People with Down syndrome have a degree of mental retardation. Heart defects are also common, but can be treated.
A trisomy. A monosomy is when there is only one of a chromosome. A trisomy is when there are three of a chromosome. In Klinefelter's syndrome, there are three sex chromosomes.