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Ploidy is the number of complete sets of chromosomes in a biological cell. In humans, the somatic cells that compose the body are diploid (containing two complete sets of chromosomes, one set derived from each parent), but sex cells (sperm and egg) are haploid. In contrast, tetraploidy (four sets of chromosomes) is a type of polyploidy and is common in plants, and not uncommon in amphibians, reptiles, and various species of insects. The number of chromosomes in a single non-homologous set is called the monoploid number (x). The haploid number (n) is the number of chromosomes in a gamete of an individual. Both of these numbers apply to every cell of a given organism. For humans, x = n = 23; a diploid human cell contains 46 chromosomes: 2 complete haploid sets, or 23 homologous chromosome pairs. In some species (especially plants), x and n differ, for example common wheat is an allopolyploid with six sets of chromosomes, two sets coming originally from each of three different species, with six sets of chromosomes in most cells and three sets of chromosomes in the gametes. The Australian bulldog ant, Myrmecia pilosula, a haplodiploid species has n = 1, the lowest known (and lowest theoretically possible) n. Euploidy is the state of a cell or organism having an integral multiple of the monoploid number, possibly excluding the sex-determining chromosomes. For example, a human cell has 46 chromosomes, which is an integer multiple of the monoploid number, 23. A human with abnormal, but integral, multiples of this full set (e.g. 69 chromosomes) would also be considered as euploid. Aneuploidy is the state of not having euploidy. In humans, examples include having a single extra chromosome (such as Down syndrome), or missing a chromosome (such as Turner syndrome). Aneuploidy is not normally considered -ploidy but -somy, such as trisomy or monosomy. From Wikipedia under the
GNU Free Documentation License  happilyhaploid.vox.com happily haploid Sun, 17 May 2009 00:09:00 GM Dr. Guy: Dan and Lori are the parents of 7 children, four of which have autism. They are at a complete loss as to why or how this happened to their family. And what amazes me is, ...  genomebiology.com Xiangyin Kong Mon, 13 Jul 2009 00:00:00 GM Given this, is there any evidence that . haploid. expression might be especially noisy, beyond any consequences of modified expression level? To determine this, we asked whether the transcriptional noise of MAs and X-linked genes is still ...  author-club.blogspot.com wiki Mon, 13 Jul 2009 09:34:00 GM The sexual phase of fungus begins when . haploid. hyphae from two separate fungi meet and fuse with each other. As a result, the cytoplasm belonging to the two different cells fuse together. However, the nuclei of the two cells remain ... From Google Blog Search: "haploid"  adamsmith.org The Adam Smith Institute, UK Our system of regulating the market in haploid cells seems to suffer from a particularly bad case of what I regard as this form of hypocrisy. Thousands of British women desperate to have a child are going abroad every year to have fertility treatment ...  nation.ittefaq.com The New Nation, Bangladesh The haploid plants can afterwards be brought back to the normal diploid status by duplicating their chromosome number through application of chemicals (such as colchicine) or other in vitro techniques. The resulting plants will therefore have two ...  genomeweb.com GenomeWeb Daily News, NY For their study, they chose 24 breast cancers 15 primary tumors and nine cell lines which they sequenced at 1-fold haploid coverage, or 6-fold physical coverage, using Illumina paired 37-base reads and 400-base pair inserts. ... From Google News Search: "haploid" What is the simple definition of the difference between a gamete and a haploid? Q. I am studying horticulture and understand that a gamete is sperm or egg. I also understand that a haploid is half... but... doesn't that make it a sperm or egg and isn't that the same? Asked by dandelion - Tue Jan 13 10:30:20 2009 - - 1 Answers - 0 Comments A. Not quite. A gamete is the actual sex cell, like sperm or egg. Haploid on the other hand is more of an adjective, describing that the gamete has half the number of chromosomes of a normal cell (which would be diploid, instead.) Answered by gandalf_for_president_3rd_age - Tue Jan 13 10:34:14 2009 What process produces gametes with a haploid number of chromosomes? Q. How does this process differ from the formation of skin cells? Asked by Johanna W - Wed Mar 26 02:07:22 2008 - - 4 Answers - 0 Comments A. Mitosis and meiosis, two processes vital to the continuation and proliferation of all life, are two similar systems by which new cells are produced by preexisting cells. However, their purpose differs. Meiosis is the process by which a sexual cell is formed. It is accomplished by one diploid forming two haploid cells. Meiosis is mainly for enhancing the probability of genetic variation. Mitosis typically occurs within body (somatic) cells (such as the skin cell) and carry a full set of chromosomes (diploid). It's purpose is to form adult organisms, regenerate and repair tissues, and is used in asexual reproduction... among other things. Simply put, creates a copy of itself. Answered by Skobert - Wed Mar 26 02:28:21 2008 What is the haploid number for an organism with 18 homologous pairs ?
Q. Just a problem solving question ! Asked by minaj, - Sun Dec 2 19:07:51 2007 - - 4 Answers - 0 Comments A. 18 homologous pairs is the diploid (pairs), so you just divide that in half = 9 Answered by cupidsmoke - Sun Dec 2 19:17:45 2007 From Yahoo Answer Search: "haploid" |
