Most cases of Down syndrome result from trisomy 21, which means each cell in the body has three copies of chromosome 21 instead of the usual two copies. The extra genetic material disrupts the normal course of development, causing the characteristic features of Down syndrome.
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When cells receive three copies of chromosome, it results in Down Syndrome.
That is Trisomy 21 also known as Down Syndrome
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Down syndrom
Down Syndrom
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Male pattern baldness is a common genetic condition passed through the X chromosome that a man gets from his mother.
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The noun wonder is a singular, common, abstract (idea) noun; a word for something extraordinary or surprising; a feeling caused by something extraordinary, mysterious, or new.
Short Answer: There are just over a thousand genes on the X chromosome and about 26 on the Y. Of the 26 on the Y, 9 relate to sperm and one (SRY) relates to male anatomy, the others involved in general tasks. The fact that there are a hundred times more genes on the X chromosome means that traits related to the X, and variations in those traits, are far far more common. Sex-linked traits are those that can only be passed along from the father and not the mother or from the mother and not the father. Obviously, males do carry and pass on sex-linked traits, just not very many. Gender can only be passed along from the father, along with genes related to sperm. Females pass on to the male offspring a larger number of traits, (such as some color blindness and male pattern baldness) which have no counterpart in the Y chromosome. More: Males have an X and a Y chromosome and females have two X chromosomes. Because the Y chromosome is smaller than the X with far fewer genes, there are genes carried only on the X and only gotten from the mother. That does not mean that all males have Y chromosomes that are the same. Overwhelmingly though, the absence of the set of genes on the Y chromosome results in the corresponding genes on the X chromosome being expressed, in particular all of the X-linked disorders of a gene of an X chromosome in a male do not have a second X gene that can be expressed to compensate. Thus, there are a set of sex-linked traits that can only come from the mother. (Color blindness and male pattern baldness are the two most discussed examples.) A male offspring (son) has the same Y chromosome as the father and hence any traits influenced by that chromosome. A female offspring (daughter) has the same X chromosome as the father and hence any traits influenced by that chromosome. A recessive gene on the X from the father will not usually be expressed in a daughter, but a dominant gene on the X from the father will be expressed in the daughter. For a female to inherit a trait associated with an X-chromosome recessive gene, there must be two copies, one from each parent. Aside: The issue of gender-connected inherited traits has much more complexity than this simple discussion can address. For example, not all of the so-called male characteristics are carried on the male (Y) chromosome. The expression of genes on other chromosomes, from both the mother and father, is influenced by genes on the Y chromosome or simply by the absence of two X chromosomes. The reader should investigate further. Caveat: This discussion applies to humans and other mammals with the XX/XY sex determination system. See related links. Fun Fact: A woman discovered that the Y chromosome was male. While studying worms, in 1905, Nettie Stevens at Bryn Mawr College identified the Y chromosome as the determining factor in gender.
Yes, the noun 'disturbance' is a common noun; a general word for something that interrupts or stops norm functioning or activities; the interruption of a settled or peaceful condition; a word for any disturbance of any kind.
Down syndrome
Down syndrome
A genetic disorder caused by the presence of all or part of a third copy of chromosome 21.
The most common condition associated with a deletion of the end of chromosome 5 is: cri-du-chat syndrome.
Hashimoto's disease is the most common hypothyroid condition caused by autoimmune factors.
Down syndrome is caused by a third copy on chromosome 21 and is present at conception or shortly after. It is mostly a random (and relatively common) occurrence, unless it is of the translocation type which is rare and genetic.
Aneuploidy, or the presence of an abnormal number of chromosomes, is the cause of several well-known genetic disorders. The most common manifestation of aneuploidy in humans is a trisomy, or having a third copy of some chromosome instead of the normal two. Here are some disorders caused by aneuploidy:Easily the best-known is Down Syndrome, which is caused by the presence of an extra chromosome 21. Down Syndrome causes various birth defects including heart failure and mental retardation, as well as a distinctive "offset" facial structure.Turner Syndrome is caused by the absence of one X chromosome in a woman (monosomy X). Most infants with Turner Syndrome are miscarried, but some survive; common symptoms include swollen appendages, underdeveloped breasts and infertility.Trisomy 18 (having an extra chromosome 18) causes high risk of miscarriage, mental deficiency and malformation of various body parts including the head, feet, fingernails and jaw.Klinefelter Syndrome is a non-life-threatening condition caused by the presence of an extra X chromosome in men; it results in a paucity of "masculine" features like armpit hair.Trisomies of many chromosomes (like 12, 13 and 18) lead to various genetic disorders that lower chances of survival at birth and cause malformation of various organs.The risks of aneuploidy rise with the mother's age. Over 40% of embryos in pregnant women aged 35 and older are abnormal. Most of these are not born, however. Nevertheless, one of every 19 children born to a 45-year-old mother has aneuploidy, as opposed to one of every 385 born to a 30-year-old.
Klinefelter syndrome is a genetic condition that results when a boy is born with an extra copy of the X chromosome. Klinefelter syndrome is a common genetic condition affecting males.
Edwards syndrome (trisomy 18) occurs more frequently in girls than boys. It is a genetic disorder caused by the presence of an extra copy of chromosome 18, leading to developmental abnormalities and various physical and mental impairments.
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.
The most common disease caused by these organisms is diarrhea, which most often affects children and younger adults.
The modal chromosome number is the most common chromosome number within a population or sample.