What is Trisomy? how many chromosomes does a human with trisomy have?
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Trisomy is a form of aneuploidy where an organism has one extra chromosome in their genone (2n + 1). So a person with trisomy will have 47 chromosome (because a normal human has 46). A common example of trisomy is Down's Syndrome.\n\nThe n in 2n stands for the number of chromosomes in a haploid cell (a gamete, or 'sex cell') of that organism. So for humans it is 23 because a full set of chromosomes (2n) in a human is 46. It's more important to remember the 2n value of a species rather than the n value, which can easily be derived if you know 2n.\n\nMendel introduced the Law of Segregation and the Law of Independent Assortment using pea plants. Any half decent biology book can explain exactly what he did and how he derived these laws.\n\nCrossing over overs during metaphase of meiosis I (or metaphase I). More precisely, but probably not importantly, it actually occurs during prometaphase which is a phase between prophase and metaphase which was derived specifically to differentiate the process of crossing over from everything else which happens in metaphase. The teaching of prometaphase is inconsistent in courses so I would just stick with metaphase I for that answer.\n\nNondisjuction is when two chromosomes stay together instead of splitting up during anaphase, which results in the production of a cell with one extra chromosome and a cell with one less chromosome. This is the primary cause of Down's Syndrome which is related to maternal age, and other types of genetic diseases.\n\nMonosomy is the opposite to trisomy, that is, an organism has a genone with one less chromosome (2n - 1). It occurs just like trisomy. A human with monosomy will therefore have 45 chromosomes.
1099493
Ahhh, no. Why would they? They don'thave 47 chromosomes.
890925
Men typically have one X chromosome and one Y chromosome in each diploid cell of their bodies. Women typically have two X chromosomes.
535424
a chromatid forms one part of a chromosome after it has coalesced for the process of mitosis or meiosis. during either process, the word "chromosome" indicates a pair of two exactly identical or "sister" chromatids joined at the central point of each chromatid, called the centromere.\n\na chromosome, by definition, has exactly one centromere. thus when sister chromatids are pulled apart by the mitotic spindle during anaphase - that is, when the centromere joining two sister chromatids splits into two centromeres - then each sister chromatid becomes an independent chromosome.\n\nin non-gametic, non-dividing human cells, there are 23 pairs of chromosomes and thus 46 chromatids.
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Downs syndrome is a trisomy of chromosome 21, the smallest human chromosome.\n\nThe vast majority of trisomies spontaneuosly abort prior to delivery, often in the first trimester of pregnancy.\n\nIt is likely that many Down sufferers escape this fate because there is less genetic coding material on C21 and therefore less overall problems recognised by mothers body systems
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I have 3 yr old boy with Trisomy 21 and have done quite a bit of research on the subject.  This is what I've found:  Women with Down syndrome can and do have children, but there is a 50 percent chance that their child will have Down syndrome. Men with Down syndrome are believed to be sterile, with only one documented instance of a male with Down syndrome who has fathered a child.
394997
chromosomal abnormalities?????hmmm....following types are the culprits:\nDisomy\n\nA disomy is the presence of a pair of chromosomes, or the normal amount for some organisms including humans. It is not a disorder, or aneuploid, but is the absence of aneuploidism.\n\n\nTrisomy\n\nA trisomy is the presence of three, instead of the normal two, chromosomes of a particular numbered type in an organism. Thus the presence of an extra chromosome 21 is called trisomy 21. Most trisomies, like most other abnormalities in chromosome number, result in distinctive birth defects. Many trisomies result in miscarriage or death at an early age.\n\nA partial trisomy occurs when part of an extra chromosome is attached to one of the other chromosomes. A mosaic trisomy is a condition where extra chromosomal material exists in only some of the organism's cells.\n\nWhile a trisomy can occur with any chromosome, few babies survive to birth with most trisomies. The most common types that survive without spontaneous abortion in humans are:\n\n    * Trisomy 21 (Down syndrome)\n    * Trisomy 18 (Edward's syndrome)\n    * Trisomy 13 (Patau syndrome)\n    * Trisomy 9\n    * Trisomy 8 (Warkany syndrome 2)\n\nTrisomy involving sex chromosomes includes:\n\n    * XXX (Triple X syndrome)\n    * XXY (Klinefelter's syndrome)\n    * XYY (XYY syndrome)\n\nDown syndrome (US, Canada and other countries) or Down's syndrome (UK and other countries) encompasses a number of chromosomal abnormalities, of which trisomy 21 (an aneuploid) is the most common, causing highly variable degrees of learning difficulties as well as physical disabilities. It is named after John Langdon Down, the British doctor who first described it in 1866.Trisomy 18 or Edwards Syndrome (named after John H. Edwards who first described the syndrome in 1960) is a genetic disorder. It is the second most common trisomy after Down's Syndrome. It is caused by the presence of three - instead of two - chromosomes 18 in a fetus or baby's cells.\n\neduard's syndrome......             The additional chromosome usually occurs before conception, when egg and sperm cells are made. A healthy egg or sperm cell contains 23 individual chromosomes - one to contribute to each of the 23 pairs of chromosomes needed to form a normal cell with 46 chromosomes. Numerical errors arise at either of the two meiotic divisions and cause the failure of segregation of a chromosome into the daughter cells (non-disjunction). This results in an extra chromosome making the haploid number 24 rather than 23. Fertilization of these eggs or sperm that contain an extra chromosome results in trisomy, or three copies of a chromosome rather than two. It is this extra genetic information that causes all the abnormalities characteristic of individuals with Edwards Syndrome. As each and every cell in their body contains extra information, the ability to grow and develop appropriately is delayed or impaired. This results in characteristic physical abnormalities such as low birth weight; a small, abnormally shaped head; small jaw; small mouth; low-set ears; and clenched fists with overlapping fingers. Babies with Edwards syndrome also have heart defects, and other organ malformations such that most systems of the body are affected.\n\nEdwards Syndrome also results in significant developmental delays. For this reason a full-term Edwards syndrome baby may well exhibit the breathing and feeding difficulties of a premature baby. Given the assistance offered to premature babies, some of these infants are able to overcome these initial difficulties, but eventually succumb.\n\nPatau syndrome, also known as trisomy 13, is a chromosomal aberration, a disease in which a patient has an additional chromosome 13.\n\nPatau syndrome is associated with severe mental retardation, small eyes that may exhibit a split in the iris (coloboma), a cleft lip and/or palate, weak muscle tone (hypotonia), an increased risk of heart defects, skeleta
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"The case of a young man with del(2) (p11.2p13) is reported. Accounts of previous cases of deletion of the short arm of chromosome 2 are reviewed. Common features include mental retardation, proportional short stature and weight, dysmorphic facial features (a prominent nose, abnormal ears), and abnormal hands. Growth and developmental delay are present during the postnatal period"\n\nhttp://jmg.bmjjournals.com/cgi/content/abstract/30/7/604
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Every human cell has 46 chromosomes. When reproducing, you cannot add all 46, otherwise your 46 plus your partner's 46 would = 92...twice the number of what it should be. SInce this is, during meiosis, the number is reduced from 46 chromosomes(23 pairs of 2) to 23 chromosomes, so you and your partner contribute and your child is normal.
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Totally 46 chromosomes.\n22 pairs will be there and two sex chromosomes will be there.\nIf male, X & Y and If Female X & X.\nSo totally 46.
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Diploid. All cells in the body that have chromosomes, except germ line cells, are diploid. One set of chromosomes from each parent.
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Down syndrome is caused by trisomy of chromosome 21, that is, an additional chromosome in what should be a pair. This happens when the separation of homologous chromosomes during meiosis is incomplete. Meiosis occurs during gametogenesis, thus if it goes wrong, the resulting gametes will be either one chromosome short or will have one too many chromosomes. If the gamete with 24 chromosomes (23 normal + 1 additional 21) achieves fertilization with a normal gamete, the zigote will have 3 copies of chromosome 21 and will develop into an individual with Down Syndrome. \nSometimes only part of the information in chromosome 21 is repeated, thus there are various "degrees" of development of the syndrome.
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I'm going to have to go with \n\nc) trysomy\n\nbecause there is NO way that it can reveal phenotype (so A and D are out).  And I know for a fact it can reveal trysomy\n\n"Karyotype analysis can detect large chromosomal abnormalities such as loss or gain of an entire chromosome or portions of a chromsome and translocations (when a portion of a chromosome breaks off and rejoins with another chromosome, a common occurrence in leukemias)."
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Go back to before the child is concieved.  Back to the creation of these specific gametes.\n\nIn the meiosis process that created the gametes, one of the gametes that eventually combined to create the person ended up having an extra chromosome.\n\nInstead of the spindle fibres pulling the chromosomes apart perfectly in half ( "n" to each pole), one side of the cell got "n-1" and one got "n+1".  The gamete with "n-1" probably died from too little information, but the one with "n+1" ended up combining into the zygote and eventually became the coding for the person with Down's syndrome.\n\nDown's syndrome has an entire extra 21 chromosome.
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If it is a diploid (2n) and has 30 chromosomes, then it has 30 chromosoms obviously but one usually addresses these as 15 pairs and not 30 chromosomes. The haploid of this would thus be 15 single chromosomes.
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Down's syndrome is a genetic disorder that was \nestablished at the moment of conception. Normally, there are 23 pairs of\nchromosomes that make up the fertilized egg. One of each pair is from\nthe sperm and the other from the egg. In Down's there is an extra \nchromosome 21. The medical term is trisomy 21. This is the usual reason\nfor Down's syndrome. \n\nThe most obvious consequences of having an extra chromosome 21 are \nan epicanthal fold around the eyes, short stature, dental deformities,\nbroad chest and mental retardation. The epicanthal fold about the eyes \ngive them an Asiatic or Mongolian appearance, hence, the older term\nmongoloid.
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Both previous answers are inaccurate.\n\nMitosis is sometimes called growth division. In plants and animals new cells are made continually. Mitosis results in two new cells identical genetically to the original which divided.\nWe are diploid animals which have 23 pairs of chromosomes. After mitosis both cells still have 23 pairs of chromosomes.\n\nMeiosis is a division which produces sex cells (sperm or ova). After division is complete, each sex cell has half the number of chromosomes; it is haploid. So instead of having 23 pairs the sex cells will have 23 chromosomes - one of each type of chromosome.