Homologous chromosomes also called homologs or homologues are chromosome pairs of approximately the same length, centromere position, and staining pattern, with genes for the same characteristics at corresponding Locus genetics loci . One Homology biology homologouschromosome is inherited from the organism ... Chromosomal crossover cross over between homologous pairs. Each chromosome in the pair contains .... Homologous chromosomes are usually similar in length, except for the sex chromosome s in several taxa , where the X chromosome is considerably larger than the Y chromosome . These sex chromosomes share only small regions of homology biology homology . Humans have 22 pairs of homologous non sex chromosomes called autosomes , and one pair of sex chromosome s, making a total of 46 chromosomes in a genetically ... to the 22 pairs of homologous autosomes, female humans have a homologous pair of sex chromosomes X chromosome two Xs , while males have an X chromosome X and a Y chromosome . Ploidy The ploidy of an organism is the number of homologous versions it has of each chromosome. If the chromosomes of an organism ... chromosome in a diploid organism has exactly one homologous partner. Each chromosome from these pairs ... Homologouschromosome sr tr Homolog kromozom uk zh ... 6624 5 ref They are usually not identical. Homologous chromosomes pair synapsis synapse during meiosis ... loci on the chromosome. However, each can contain either the same allele e.g., both alleles for blue ... from two parents . In fact the chromosomes physically arrange themselves into homologous pairs ... have more than two homologous chromosomes. Sister chromatids In meiosis sister chromatid s are each strand of the conjoined chromosomes which result from the replication and crossover of homologous ... of chromosome replication prior to separation during the anaphase . See also Synteny References ... NCBI link to Gene Homology resources, and Comparative Chromosome Maps of the Human, Mouse ... more details
Diagram of a replicated and condensed metaphase eukaryotic chromosome. 1 Chromatid one of the two identical parts of the chromosome after S phase . 2 Centromere the point where the two chromatids touch, and where the microtubules attach. 3 Short arm. 4 Long arm. A chromosome is an organized ... P, Salse J, et al. title A Physical Map of the 1 Gigabase Bread Wheat Chromosome 3B journal Science ... there are many exceptions to this rule. Also, cells may contain more than one type of chromosome ... leading to the progression of cancer . In practice chromosome is a rather loosely defined term .... However, a large body of work uses the term chromosome regardless of chromatin content. In prokaryotes ... lack structural proteins. Citation needed date February 2012 explain The word chromosome comes from ... right thumb 190px Walter Sutton left and Theodor Boveri right independently developed the chromosome .... Citation needed date April 2009 Wilhelm Roux suggested that each chromosome carries a different ... 1902 by naming the chromosome theory of inheritance the Boveri Sutton Chromosome Theory Sutton ... Morgan , all of a rather dogmatic turn of mind. Eventually, complete proof came from chromosome maps ... In eukaryotes See also Eukaryotic chromosome fine structure Eukaryotes cell biology cells with nuclei ... in the cell s nucleus. Each chromosome has one centromere , with one or two arms projecting from ... as it is in part based on gene prediction s. Total chromosome length is an estimate as well ... frame Estimated number of genes and base pairs in mega base pairs on each human chromosome class wikitable sortable style text align right Chromosome Genes Total Nucleobase base pairs Sequenced ... information on the Human Genome Project. ref Chromosome 1 human 1 4,220 247,199,719 224,999,719 Chromosome 2 human 2 1,491 242,751,149 237,712,649 Chromosome 3 human 3 1,550 199,446,827 194,704,827 Chromosome 4 human 4 446 191,263,063 187,297,063 Chromosome 5 human 5 609 180,837,866 177,702,766 ... more details
Image HR in meiosis.svg thumb 275px alt Depiction of chromosome 1 after undergoing homologous recombination in meiosis Figure 1. During meiosis , homologous recombination can produce new combinations of genes as shown here between homologouschromosome similar but not identical copies of human chromosome 1 human chromosome 1 . Homologous recombination is a type of genetic recombination in which nucleotide ... a double strand chromosome break by homologous recombination revisiting Robin Holliday s model ... chromosome. In contrast to homologous recombination, NHEJ is predominant in the G1 phase G sub ... a similar but not necessarily identical homologouschromosome. ref name Sung A displacement loop ... , effectively restoring the strand on the homologouschromosome that was displaced during strand ... filament then searches out similar sequences of DNA on a homologouschromosome. The search process induces ... as double strand breaks. Homologous recombination also produces new combinations of DNA sequences ... 48122761 57023651 69932405 ref Homologous recombination is also used in horizontal gene transfer ... homologous recombination varies widely among different organisms and cell types, most forms involve ... molecules. Depending on how the two junctions are cut by enzyme s, the type of homologous recombination that occurs in meiosis results in either chromosomal crossover or non crossover. Homologous recombination ... the damaged DNA molecule as it existed before the double strand break. Homologous recombination ... es, suggesting that it is a nearly universal biological mechanism. The discovery of genes for homologous ... homologous recombination are topics of active research. Homologous recombination is also ... and gene 496 ref where one of the linked genes physically crosses over to a different chromosome ... a model now known as the Homologous recombination DSBR pathway DSBR pathway , which accounted for observations ... , budding yeast and mammalian cells led to the emergence of other models of homologous recombination ... more details
Orphan date April 2012 Homologous desensitization occurs when a Receptor biochemistry receptor decreases its response to a signalling molecule when that agonist is in high concentration. ref cite web title homologous desensitization url http www.drugs.com dict homologous desensitization.html work Medical Dictionary publisher Drugs.com accessdate 18 May 2011 ref It is a process whereby after prolonged agonist exposure, the receptor is uncoupled from its signaling cascade, and thus the biological effect of receptor activation is attenuated. ref cite journal last Fehmann first HC coauthors Habener, JF title Homologous desensitization of the insulinotropic glucagon like peptide I 7 37 receptor on insulinoma HIT T15 cells. journal Endocrinology date 1991 Jun volume 128 issue 6 pages 2880 8 pmid 1645253 accessdate 18 May 2011 doi 10.1210 endo 128 6 2880 ref Homologous desensitization should not be confused with heterologous desensitisation , which is a different process whereby repeated stimulation of a receptor by one agonist results in desensitivity to a range of other agonists. Mechanism The mechanism of homologous desensitization is as follows using the Beta 2 adrenergic receptor sub 2 sub receptor as an example Agonist binds and activates receptor which changes to an active conformational state. Beta adrenergic receptor kinase BARK , a cytoplasmic kinase is activated and phosphorylation phosphorylates the C terminus of the sub 2 sub receptor. Such phosphorylation increases the affinity of arrestin arrestin for the receptor, resulting in uncoupling of the Gs alpha subunit subunit of the G proteins heterotrimeric G protein from the receptor producing desensitization. References reflist Category Membrane biology Category G protein coupled receptors Category Signal transduction sr Homologna desenzitizacija ... more details
Unreferenced stub auto yes date December 2009 Homologous temperature expresses the temperature of a material as a fraction of its melting point temperature using the Kelvin scale . For example, the homologous temperature of lead at room temperature is approximately 0.50 T sub H sub T T sub mp sub 298K 601K 0.50 . Solder T sub mp sub 183 C 456K at 0.85T sub mp sub or 115 C 388K , would thus be expected to have comparable properties to copper T sub mp sub 1085 C 1358K at 0.85T sub mp sub or 881 C 1154K . In electronics applications, where circuits typically operate over a 55 C to 125 C range, eutectic tin lead Sn63 solder is working at 0.48T sub mp sub to 0.87T sub mp sub . The upper temperature is high relative to the melting point from this we can deduce that solder will have limited mechanical strength as a bulk material and significant Creep deformation creep under stress. This is borne out by its comparatively low values for tensile strength, shear strength and modulus of elasticity. Citation needed date April 2009 Copper, on the other hand, has a much higher melting point, so foils are working at only 0.16T sub mp sub to 0.29T sub mp sub , and their properties are little affected by temperature. DEFAULTSORT Homologous Temperature Category Units of temperature Physics stub Measurement stub ... more details
In chemistry , a homologous series is a series of compounds with a similar General formula General forms for organic compounds general formula , possessing similar chemical properties due to the presence of the same functional group , and showing a gradation in physical properties as a result of increase in molecular size and mass see relative molecular mass . For example, ethane has a higher boiling point than methane since it has more Van der Waals forces intermolecular forces with neighbouring molecules. This is due to the increase in the number of atoms making up the molecule. Alkane s paraffin s , alkene s olefins , ethers , and alkyne s acetylene s form such series in which members differ in mass by 14 atomic mass units. For example, the alkane homologous series begins with methane CH sub 4 sub , ethane C sub 2 sub H sub 6 sub , propane C sub 3 sub H sub 8 sub , butane C sub 4 sub H sub 10 sub , and pentane C sub 5 sub H sub 12 sub , each member differing from the previous one by a CH sub 2 sub group or 14 atomic mass units . The CH sub 2 sub group is called Methylene Group. Similarly, there is the alcohol homologous series that starts with methanol CH sub 4 sub O , ethanol C sub 2 sub H sub 6 sub O , as primary alcohols, isopropanol C sub 3 sub H sub 8 sub O as a simple secondary alcohol, and a simple tertiary alcohol is tert butanol tert butanol C sub 4 sub H sub 10 sub O . Even though the general formula remains constant in a homologous series, specific members of the series ... groups . center table border 0 style text align center tr td Homologous series td td General ... reaction is any chemical process which converts one member of a homologous series to the next member. Inorganic Homologous Series Commons category Homologous series Homologous series are not unique to organic chemistry . Titanium , vanadium , and molybdenum oxides all form homologous series ... 2009 DEFAULTSORT Homologous Series Category Organic chemistry ar bg cs Homologick ... more details
Chromosome segregation is a step in cell reproduction or division, where chromosomes pair off with their similar homologouschromosome. In mitosis , a complete copy of each one is made. In meiosis , one chromosome from each pair migrates to opposite ends of the cell and the genes are split to make a gamete. ref cite book last Deppe first Carol title Breed your own Vegetable Varieties publisher Little, Brown & Company date 1993 pages 96 97 isbn 0 316 18104 8 ref For more information see Cell Cycle the Cell Cycle . References div class references small style moz column count 2 column count 2 references div Category Chromosomes ... more details
Artificial chromosome may refer to Yeast artificial chromosome Bacterial artificial chromosome Human artificial chromosome P1 derived artificial chromosome disambig Long comment to avoid being listed on short pages ... more details
Supernumerary chromosome could refer to B chromosome in some animals and plants Small supernumerary marker chromosome sSMC in humans disambig ... more details
of its genes on itself instead of having a second, homologous, chromosome. When errors occur, it can ...Image Chromosome Y.svg 125px right thumb Human Y chromatid The Y chromosome is one of the two Sex determination system sex determining chromosome s in most mammal s, including human s. In mammals, it contains the gene SRY , which triggers testicle testis development if present. The human Y chromosome is composed of about 50 million base pairs . DNA in the Y chromosome is passed from father to son, and Y ..., the Y chromosome is one of the fastest evolving parts of the human genome. ref cite news last Wade first Nicholas title Male Chromosome May Evolve Fastest url http www.nytimes.com 2010 01 ... one pair of sex chromosomes in each cell. Males have one Y chromosome and one X chromosome , while females have two X chromosomes. In mammals, the Y chromosome contains a gene, SRY , which triggers embryonic ... system Z chromosome , ref name Warren cite journal author Warren WC, Hillier LDW, Graves ... Before Y chromosome Many ectotherm ic vertebrates have no sex chromosomes. If they have different ... cite journal author Muller, HJ title A gene for the fourth chromosome of Drosophila journal Journal ... ref name lahn cite journal author Lahn B, Page D title Four evolutionary strata on the human X chromosome ... caused the organism to be male. ref name Graves, J.A.M 2006 The chromosome with this allele became the Y chromosome, while the other member of the pair became the X chromosome. Over time, genes ... chromosome, or were acquired through the process of chromosomal translocation translocation . ref ... ancestral monotreme X chromosome year 1992 journal Chromosoma volume 101 issue 10 pages 596 ... on the Y chromosome, and females with unnecessary or even harmful genes previously only found on the Y chromosome. As a result, genes beneficial to males accumulated near the sex determining genes, and recombination ... Graves, J.A.M 2006 Over time, the Y chromosome changed in such a way as to inhibit the areas around ... more details
crossing over genetic recombination between homologouschromosome s during meiosis . Balancers ... chromosome journal Nature Genetics year 1998 volume 22 pages 375 378 url http www.nature.com ng ... PMC1212546 pdf 235.pdf Analysis of Chromosome 4 in Drosophila Melanogaster11 Ethyl Methanesulfonate Induced Lethals . ref cite journal last HOCHMAN first BENJAMIN title ANALYSIS OF CHROMOSOME 4 IN DROSOPHILA ... journal last Herman first Robert coauthors Donna, Albertson, Sydney, Brenner title Chromosome Rearrangements ... homologous chromosomes is disrupted. This construct is called a crossover suppressor . ref cite ..., Allan Bradley & Monica J. Justice title Functional genetic analysis of mouse chromosome 11 journal ... a balancer chromosome and the balancer s homolog does occur during meiosis each chromatid ends ... that make pigments allow researchers to easily recognize flies that carry the balancer chromosome ... reproductive fitness when carried homozygously a balancer chromosome ensures that the population it is carried in does not become fixed for the balancer chromosome. Balancer chromosomes always contain ... chromosome, one from the mother and one from the father, then the organism will not live. So any organism that is homozygous for that chromosome will not live to pass on its genes. However, offspring that only get one copy of one balancer chromosome and one copy of a wild type or mutant chromosome will live ... in the chromosome such as the Green Florescent Protein that fluoresces in ultraviolet light, or it can ... chromosomes are named for the chromosome they serve to stabilize and for the phenotypic or genetic ... letter of the chromosome s name represents the number of the chromosome it stabilizes. F stands for the first chromosome, S stands for second, and T stands for third. The small fourth chromosome ... chromosome. Additionally, the genetic marker or markers of the balancer are listed after the name and separated ... are heterozygous. For example, the commonly used TM3, Sb balancer is a balancer chromosome that stabilizes ... more details
Multiple issues orphan March 2011 unreferenced October 2010 expert subject March 2011 The polycentric chromosome is when more than 2 chromosome are present e.g. par ascaris 2 chromosome Mucor hiemalis in plant s have 2 chromosome. Adder s tongue fern have 1262 chromosome. In auto cantha or radiolorian there are 1682 chromosome. DEFAULTSORT Polycentric Chromosome Category Chromosomes genetics stub ... more details
play a positive role on normal A chromosomes in some circumstances. The B chromosomes suppress homologous pairing which reduces multiple pairing between homologous chromosomes in Allopolyploidy allopolyploids . Bivalent pairing is ensured by a gene on chromosome 5 of the B genome Phlocus. The B chromosomes ... infertility. B chromosomes are not to be confused with marker chromosome s or additional copies of normal chromosomes as they occur in Trisomy Trisomies . Supernumerary chromosomes in fungi Chromosome ... a different chromosome number, with some of these additional chromosomes being unnecessary for normal ... chromosome of the pea pathogen Haematonectria haematococca carries genes that are important to the disease ... JP, Sharbel TF, Beukeboom LW title B chromosome evolution journal Philos. Trans. R. Soc. Lond ... M, L pez Le n MD, Camacho JPM title Rapid suppression of drive for a parasitic B chromosome journal ... issue 2 4 cite journal author Bakkali M, Camacho JP title The B chromosome polymorphism of the grasshopper Eyprepocnemis plorans in North Africa. IV. Transmission of rare B chromosome variants journal ... author Bakkali M, Camacho JP title The B chromosome polymorphism of the grasshopper Eyprepocnemis ... are an unlikely pathway for B chromosome integration into the standard genome journal Chromosome ... M, Perfectti F, Camacho JP title The B chromosome polymorphism of the grasshopper Eyprepocnemis ... of a parasitic B chromosome in the grasshopper Eyprepocnemis plorans journal Chromosome Research ... Common origin of B chromosome variants in the grasshopper Eyprepocnemis plorans journal Heredity ... journal author Bakkali M, Cabrero J, Lopez Leon MD, Perfectti F, Camacho JP title The B chromosome ... B chromosome polymorphism in North African natural populations of the grasshopper Eyprepocnemis ... B Chromosomes http www.studenec.ivb.cz Projects B chromosome index.php B chromosomes ... more details
Unreferenced date December 2009 Chromosome jumping is a tool of molecular biology that is used in the physical genome project mapping of genome s. It is related to several other tools used for the same purpose, including chromosome walking . Chromosome jumping is used to bypass regions difficult to cloning clone , such as those containing repetitive DNA , that cannot be easily mapped by chromosome walking, and is useful in moving along a chromosome rapidly in search of a particular gene . In chromosome jumping, the DNA of interest is identified, cut into fragments with restriction enzyme s, and circularised the beginning and end of each fragment are joined together to form a circular loop . From a known DNA sequence sequence a primer molecular biology primer is designed to DNA sequencing sequence across the circularised junction. This primer is used to jump 100 base pair kb 300 kb intervals a sequence 100 kb away would have come near the known sequence on circularisation. Thus, sequences not reachable by chromosome walking can be sequenced. Chromosome walking can be used from the new jump position in either direction to look for gene like sequences, or additional jumps can be used to progress further along the chromosome. See also Shotgun sequencing Chromosome walking Chromosome landing DEFAULTSORT Chromosome Jumping Category Laboratory techniques Category Molecular biology Category DNA Molecular cell biology stub ca Jumping es Salto cromos mico fr Saut sur le chromosome ... more details
Orphan date February 2009 A derivative chromosome der is a structurally rearranged chromosome generated either by a rearrangement involving two or more chromosomes or by multiple aberrations within a single chromosome e.g. an inversion and a deletion of the same chromosome, or deletions in both arms of a single chromosome . http ghr.nlm.nih.gov ghr glossary derivativechromosome The term always refers to the chromosome that has an intact centromere. Derivative chromosomes are designated by the abbreviation der when used to describe a Karyotype . The derivative chromosome must be specified in parentheses followed by all aberrations involved in this derivative chromosome. The aberrations must be listed from pter to qter and not be separated by a comma. For example, 46,XY,der 4 t 4 8 p16 q22 t 4 9 q31 q31 would refer to a derivative chromosome 4 which is the result of a translocation between the short arm of chromosome 4 at band 16 and the long arm of chromosome 8 at band 22, and a translocation between the long arm of chromosome 4 at band 31 and the long arm of chromosome 9 at band 31. Derivative chromosomes and other abnormalities could be drawn online using CyDAS online tools Hiller B, Bradtke J, Balz H and Rieder H 2004 CyDAS Online Analysis Site , http www.cydas.org OnlineAnalysis References An International System for Human Cytogenetic Nomenclature, Shaffer, L.G., Tommerup N. eds S. Karger, Basel 2005 Category Chromosomes genetics stub ... more details
File Single Chromosome Mutations.png thumb right The three major single chromosome mutations deletion 1 , duplication 2 and inversion 3 . File Two Chromosome Mutations.png thumb right The two major two chromosome mutations insertion 1 and Translocation 2 . A chromosome anomaly , abnormality or aberration reflects an atypical number of chromosome s or a structural abnormality in one or more chromosomes ... karyotype for the species via genetic testing . A chromosome anomaly may be detected or confirmed in this manner. Chromosome anomalies usually occur when there is an error in cell division following meiosis or mitosis . There are many types of chromosome anomalies. They can be organized into two ... number of chromosomes , and occurs when an individual is missing either a chromosome from ... with Down Syndrome has three copies of chromosome 21, rather than two . Turner Syndrome is an example of a monosomy where the individual is born with only one sex chromosome, an X. Structural abnormalities When the chromosome s structure is altered, this can take several forms Deletion genetics Deletions A portion of the chromosome is missing or deleted. Known disorders in humans include Wolf Hirschhorn syndrome , which is caused by partial deletion of the short arm of chromosome 4 ... A portion of the chromosome is duplicated, resulting in extra genetic material. Known human ... may be caused by duplication of the gene encoding peripheral myelin protein 22 PMP22 on chromosome 17. Chromosomal translocation Translocation s A portion of one chromosome is transferred to another chromosome. There are two main types of translocations Chromosomal translocation Reciprocal non Robertsonian ... exchanged. Robertsonian translocation An entire chromosome has attached to another at the centromere ... A portion of the chromosome has broken off, turned upside down and reattached, therefore the genetic material is inverted. Insertion genetics Insertions A portion of one chromosome has been deleted from ... more details
Chromosome engineering is the controlled generation of chromosomal deletions, inversions, or translocations with defined endpoints. ref Reviews Glossary. nature.com. N.p., n.d. Web. 15 Oct. 2009. http www.nature.com nrg journal v6 n7 glossary nrg1638 glossary.html. ref By combining chromosomal translocation , chromosomal inversion ,and chromosomal deletion , chromosome engineering has been shown to identify the underlying genes that cause certain diseases in mice. In coming years, it is very likely that chromosomal engineering will be able to do the same identification for diseases in humans, as well as all other organisms. ref Ramirez Solis, R., P. Liu, and A. Bradley. Chromosome Engineering in Mice. Public Med. N.p., n.d. Web. 17 Oct. 2009. http www.ncbi.nlm.nih.gov pubmed 7501018 . ref The Three Types of Chromosome Engineering class wikitable chromosomal deletion chromosomal inversion chromosomal translocation Chromosomal deletion is a mutation a genetic aberration in which a part of a chromosome or a sequence of DNA is missing. Chromosomal inversion is a chromosome rearrangement in which a segment of a chromosome is reversed end to end. Chromosomal translocation is a chromosome abnormality caused by rearrangement of parts between nonhomologous chromosomes. Experiments of Chromosome Engineering In an experiment pertaining to chromosome engineering that was conducted in 2006, it was found that chromosome engineering can be effectively used as a method of identifying the causes of genetic disorders such as the continuous gene and aneuploidy syndromes. The experiment was conducted by infecting mice with the human disease, ES, to see the effectiveness of chromosomal engineering ... chromosomes, or chromosome engineering, is an excellent and efficient method of determining underlying genes in genetic orders and diseases. In the future, chromosome engineering will experiment .... See also Genetics Chromosome Chromosomal deletion Chromosomal inversion Chromosomal translocation ... more details
Unreferenced auto yes date December 2009 The part of chromosome beyond the nuclear organiser is very short and appears like sphere satellite .The Satellite Chromosome is the chromosome which has a bulge on the telomeric end and SAT stands for Sine Acid thymonucleinico without thymonucliec acid or DNA since the chromosome on staining show relative deficiency of DNA in the nuclear organiser region.There are at least 2 SAT chromosomes in each diploid nucleus.It plays a vital role in the formation of the nucleolous after division is completed. It shows repetitive sequences of genes. Besides centromere , secondary constriction can also be observed in some chromosomes, which if present in the distal region of the arm, would pinch off a small fragment called Satellite . The satellite remains attached to the rest of the body of chromosome s by a thread of chromatin . The secondary constrictions are always constant in their positions and hence can be used as markers . The chromosomes having a satellite are marker chromosomes and are also called SAT chromosomes .these SAT chromosomes are helpful in transferring details to mRNA. DEFAULTSORT Satellite Chromosome Category Genetics Category Chromosomes Genetics stub pl Trabant biologia ... more details
unreferenced date September 2009 Image with unknown copyright status removed Image Centromere.png right Image Chromosome upright.png frame Diagram of a duplicated and condensed metaphase eukaryotic chromosome. 1 Chromatid one of the two identical parts of the chromosome after S phase . 2 Centromere the point where the two chromatids touch, and where the microtubules attach. 3 Short arm p . 4 Long arm q . Several chromosome regions have been defined by convenience in order to talk about gene locations. Most important is the distinction between chromosome region p and chromosome region q . These are Virtuality virtual regions that exist in all chromosome s. During cell division , the molecules that compose chromosomes DNA and protein s suffer a condensation process called the chromatin condensation , and forms a compact and small complex called a chromatid. In diploid organisms, sister chromatids are attached to each other by the centromere . The centromere divides each chromosome into two regions the smaller one, which is the p region, and the bigger one, the q region. Usually, as a convention, the p region is represented in the upper part of an image while the q region is in the bottom part. At either end of a chromosome is a telomere , a cap of DNA that protects the rest of the chromosome from damage. The areas of the p and q regions close to the telomeres are the subtelomere s, or subtelomeric regions. The areas closer to the centromere are the pericentronomic regions. Finally, the interstitial regions are the parts of the p and q regions that are close to neither the centromere nor the telomeres, but are roughly in the middle of p or q . Image subtelomere copy.jpg left DEFAULTSORT Chromosome Regions Category Chromosomes ... more details
Unreferenced stub auto yes date December 2009 Dicentric chromosome is an aberrant chromosome having two centromere s. Dicentric chromosomes form when two chromosome segments from different chromosomes or from the two chromatids of a single one , each with a centromere, fuse end to end, with loss of their acentric fragments. Dicentrics, despite their two centromeres, may be mitotically stable if one of the two centromeres is inactivated, or if the two centromeres always coordinate their movement to one or the other pole during anaphase. Such chromosomes are formally called pseudodicentric. The most common pseudodicentrics involve the sex chromosomes or the acrocentric chromosomes Robertsonian translocation . Evaluation of centromere function by Fluorescent in situ hybridization FISH combined with immunofluorescence analysis of centromere and kinetochore proteins is a specialized procedure in some clinical cytogenetics laboratories. DEFAULTSORT Dicentric Chromosome Category Chromosomes Genetics stub ... more details
Image Chromosome X.svg 125px thumb right Scheme of the X chromatid Image Sd4hi unten crop.jpg thumb Nucleus of a female amniotic fluid cell. Top Both X chromosome territories are detected by Fluorescence ... . The X chromosome is one of the two sex determination system sex determining chromosome s in many animal species, including mammals the other is the Y chromosome and is found in both males and females. It is a part of the XY sex determination system and X0 sex determination system . The X chromosome ... Y chromosome, for the next letter in the alphabet, after it was discovered later. ref name nyt angier cite web url http www.nytimes.com 2007 05 01 science 01angi.html title For Motherly X Chromosome ... 01 accessdate 2007 05 01 ref In humans Function The X chromosome in humans spans more than 153 million ... in each cell. Females have two X chromosomes, whereas males have one X and one Y chromosome . Both males and females retain one of their mother s X chromosomes, and females retain their second X chromosome from their father. Since the father retains his X chromosome from his mother, a human female has one X chromosome from her paternal grandmother father s side , and one X chromosome from her mother. Identifying genes on each chromosome is an active area of genetic research. Due to the fact that researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. The X chromosome contains about 2000 ref name Macmillan Science Library cite web author Macmillan Science Library title Genetics on X Chromosome year 2001 ref genes compared to the Y chromosome containing 78 ref name Harris cite web author Richard Harris title Scientists Decipher Y Chromosome url http www.npr.org templates story story.php?storyId 1303260 year 2003 ref genes ... to mutation s in genes on the X chromosome are described as X linked . The X chromosome carries ... ensures that females, like males, have one functional copy of the X chromosome in each body cell ... more details
band of interest, and, using a very fine needle, tears that band away from the rest of the chromosome ... region of the chromosome in question. References Scalenghe F, Turco E, Edstrom JE, Pirrotta V, Melli ... more details
A marker chromosome mar is a structurally abnormal chromosome in which no part can be identified. The significance of a marker is very variable as it depends on what material is contained within the marker. It is essentially a partial trisomy . However sometimes the marker is composed of inactive genetic material and has little or no effect. There are some markers that are passed down through a family with little effect. There are some markers that arise as new events. Often, markers are not passed down as they can be lost during cell division due to their small size. There are some individuals who have multiple markers. When special studies are performed to identify the material more conclusions can be drawn about the effects of the marker. There is a more common marker called inverted duplication of chromosome 15. This is a specific syndrome that has developmental delays and physical variations and often seizures as its features. A difficult situation arises when a marker chromosome is found on a prenatal study such as amniocentesis. If the marker is not one of the more common markers and neither parent has the marker, it can be very difficult to predict the effects of the marker. Usually, if a parent carries the same marker, the effect is much less. References http www.chromodisorder.org sytrix card list.php3?dbid 63&id 365 An International System for Human Cytogenetic Nomenclature, Shaffer, L.G., Tommerup N. eds S. Karger, Basel 2005 dead link Category Chromosomes ca Cromosoma marcador de Markerchromosom it Cromosoma marcatore pl Chromosom markerowy fi Marker kromosomi ... more details
Orphan date April 2012 The genetics genetic technique of chromosome landing is a method of molecular cloning cloning of a gene of interest from a clone library . It is based on the principle that the expected average between genetic marker marker genetic distance distance s can be smaller than the average insert length of a clone library containing the gene of interest. From the abstract of PMID 7716809 The strategy of chromosome walking is based on the assumption that it is difficult and time consuming to find DNA markers that are physically close to a gene of interest. Recent technological developments invalidate this assumption for many species. As a result, the mapping paradigm has now changed such that one first isolates one or more DNA marker s at a physical distance from the targeted gene that is less than the average insert size of the genomic library being used for clone isolation. The DNA marker is then used to Genetic screen screen the library and isolate or land on the clone containing the gene, without any need for chromosome walking and its associated problems. Chromosome landing, together with the technology that has made it possible, is likely to become the main strategy by which map based cloning is applied to isolate both major genes and genes underlying quantitative traits in plant species. See also Primer walking Category Molecular biology Category Genetic engineering ar ... more details
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