2007-01-18 09:50:48 · 9 answers · asked by Siminator 2 in Science & Mathematics ➔ Biology
Down Syndrome is caused by trisomy 21, which means that the person has three copies, instead of two, of the 21st chromosome.
Down Syndrome doesn't effect genes - it's *caused by* too many copies of a whole chromosome's worth of genes.
2007-01-18 09:54:08 · answer #1 · answered by Brian L 7 · 2⤊ 0⤋
I agree with the above answerer: But here's a start 1. if it is sex linked, which parent passes the trait to the child? It isn't sex linked. Down syndrome can come from either parent. 2. how is it inherited? It isn't inherited. It's a malfunction of cell division before or after fertilisation. 3. is it a dominant trait or a recessive trait or a incomplete dominance? None of those. 4. is it due to lack of chromosomes or extra chromosomes? One extra chromosome. 5. has a gene been located that causes this disorder? No 6. if a gene has been located, what chromosomes is it located on? No. It's too much genetic material. 7. what chromosome is effected? 21? -You mean affected. Yes. Trisomy 21
2016-05-24 04:40:00 · answer #2 · answered by Anonymous · 0⤊ 0⤋
Down syndrome is a chromosomal abnormality characterized by the presence of an extra copy of genetic material on the 21st chromosome, either in whole (trisomy 21) or part (such as due to translocations). The effects of the extra copy vary greatly among individuals, depending on the extent of the extra copy, genetic background, environmental factors, and random chance. Down syndrome occurs in all human populations, and analogous effects have been found in other species such as chimpanzees[6] and mice. Recently, researchers have created transgenic mice with most of human chromosome 21 (in addition to the normal mouse chromosomes).[7] The extra chromosomal material can come about in several distinct ways. A normal human karyotype is designated as 46,XX or 46,XY, indicating 46 chromosomes with an XX arrangement for females and 46 chromosomes with an XY arrangement for males.[8]
2007-01-18 09:53:46 · answer #3 · answered by whoami 2 · 1⤊ 1⤋
I want to believe that down syndrome is caused by a mutation of the 21 chromosome if you are viewing a carotype.
2007-01-18 10:58:05 · answer #4 · answered by Anonymous · 0⤊ 0⤋
Down syndrome is located in the cells. It's part of their genetics. What causes it is during mitosis one cell ends up having 45 chromosomes and one has 47. Instead of both having 46.
2007-01-18 10:01:19 · answer #5 · answered by Anonymous · 0⤊ 0⤋
It affects a whole host of genes. It is caused by an extra copy of an entire chromosome, 21.
2007-01-18 09:54:22 · answer #6 · answered by Ellie S 4 · 1⤊ 0⤋
It's where you have three 21 chromosomes instead of two and it's located in the DNA of an organism/person. It's a genetic disorder, or something of a mutation. Most babies don't make it to birth and those that actually live are what we consider "mentally challenged".
2007-01-18 09:56:19 · answer #7 · answered by ? 3 · 1⤊ 0⤋
Down syndrome is caused by trisomy 21 which is the existence of all of or part of a third stand of the 21st chromosome.
Shame on you for copy and pasting whoami.
2007-01-18 09:53:43 · answer #8 · answered by San Jose 3 · 2⤊ 0⤋
is a genetic disorder caused by the presence of all or part of an extra 21st chromosome
2007-01-18 09:55:04 · answer #9 · answered by meghal_shah29 1 · 1⤊ 0⤋