TY - JOUR. T1 - Differential expression of steroid sulphatase locus on active and inactive human X chromosome. AU - Migeon, Barbara R. AU - Shapiro, Larry J.. AU - Norum, Robert A.. AU - Mohandas, Thuluvancheri. AU - Axelman, Joyce. AU - Dabora, Rebecca L.. PY - 1982. Y1 - 1982. N2 - The X chromosome in mammalian somatic cells is subject to unique regulation - usually genes on a single X chromosome are expressed while those on other X chromosomes are inactivated1. The X-locus for steroid sulphatase (STS; EC 3.1.6.2), the microsomal enzyme that catalyses the hydrolysis of various 3β-hydroxysteroid sulphates, is exceptional because it seems to escape inactivation. Evidence for this comes from fibroblast clones in females heterozygous for mutations that result in a severe deficiency of this enzyme in affected males; all clones from these heterozygotes have STS activity, and enzyme-deficient clones that are expected if the locus were subject to inactivation2, have not been found3. Further evidence ...
Genomic imprinting is one of the well-known epigenetic factors causing the association between traits and genes, and has generally been examined by detecting parent-of-origin effects of alleles. A lot of methods have been proposed to test for parent-of-origin effects on autosomes based on nuclear families and general pedigrees. Although these parent-of-origin effects tests on autosomes have been available for more than 15 years, there has been no statistical test developed to test for parent-of-origin effects on X chromosome, until the parental-asymmetry test on X chromosome (XPAT) and its extensions were recently proposed. However, these methods on X chromosome are only applicable to nuclear families and thus are not suitable for general pedigrees. In this article, we propose the pedigree parental-asymmetry test on X chromosome (XPPAT) statistic to test for parent-of-origin effects in the presence of association, which can accommodate general pedigrees. When there are missing genotypes in some
The X chromosome in humans spans more than 153 million base pairs (the building material of DNA). It represents about 800 protein-coding genes compared to the Y chromosome containing about 70 genes, out of 20,000-25,000 total genes in the human genome. Each person usually has one pair of sex chromosomes 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 mothers 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 (fathers side), and one X chromosome from her mother. This inheritance pattern follows the Fibonacci numbers at a given ancestral depth. Genetic disorders that are due to mutations in genes on the X chromosome are described as X linked. The X chromosome carries hundreds of genes but few, if any, of these have anything to do directly with sex ...
Header}} ==Introduction== [[File:Human X chromosome.jpg,thumb,300px,Human X chromosome]] Humans have 23 pairs of chromosomes, 22 autosomes and a pair of sex chromosomes. Females have a pair of X chromosomes (46, XX) and males have one X and one [[Y_Chromosome,Y Chromosome]] (46, XY). This section of notes introduces the X chromosome and its role in development. There is a separate page discussing [[Molecular_Development_-_X_Inactivation,X Inactivation]] that occurs in female development to provide the correct gene dosage. * Genes such as Wnt-4 and DAX-1 necessary for initiation of female pathway ovary development * An early discovery (1961) was that in order to have correct levels of X chromosome gene/protein expression (gene dosage), females must inactivate a single copy of the X chromosome in each and every cell. The initiator of the X inactivation process was discovered (1991) to be regulated by a region on the inactivating X chromosome encoding an X inactive specific ...
X monosomic mice (39,XO) have a remarkably mild phenotype when compared to women with Turner syndrome (45,XO). The generally accepted hypothesis to explain this discrepancy is that the number of genes on the mouse X chromosome which escape X inactivation, and thus are expressed at higher levels in females, is very small. However this hypothesis has never been tested and only a small number of genes have been assayed for their X-inactivation status in the mouse. We performed a global expression analysis in four somatic tissues (brain, liver, kidney and muscle) of adult 40,XX and 39,XO mice using the Illumina Mouse WG-6 v1_1 Expression BeadChip and an extensive validation by quantitative real time PCR, in order to identify which genes are expressed from both X chromosomes. We identified several genes on the X chromosome which are overexpressed in XX females, including those previously reported as escaping X inactivation, as well as new candidates. However, the results obtained by microarray and qPCR were
Ive made an X chromosome model that predicts shared X DNA percentages and ranges for various ancestors, but I havent yet calculated ranges for siblings or any other relatives. Anyway, this is a simple probability question.. Sometimes people get a certain axiom reversed and it isnt necessarily true anymore. The correct axiom is that two sisters who dont share one full X chromosomes (out of two copies each) cannot share a father, i.e. they must be half-sisters who share a mother. The way to get it backwards is to say that, if two sisters share one full copy of an X chromosome, that they must share a father. Now, I dont know what the probability is of an exception occurring to the incorrectly-stated axiom, but I know it isnt zero, and we can probably get a good approximation of the percentage.. 14% of the time the X chromosome doesnt recombine in mothers. This means, if were assuming that events are independent, the chances that any two siblings will have X chromosomes that werent ...
Unlike the autosomes, recombination between the X chromosome and Y chromosome is often thought to be constrained to two small pseudoautosomal regions (PARs) at the tips of each sex chromosome. The PAR1 spans the first 2.7 Mb of the proximal arm of the human sex chromosomes, while the much smaller PAR2 encompasses the distal 320 kb of the long arm of each sex chromosome. In addition to the PAR1 and PAR2, there is a human-specific X-transposed region that was duplicated from the X to the Y. The X-transposed region is often not excluded from X-specific analyses, unlike the PARs, because it is not thought to routinely recombine. Genetic diversity is expected to be higher in recombining regions than in non-recombining regions because recombination reduces the effect of linked selection. In this study, we investigate patterns of genetic diversity in noncoding regions across the entire X chromosome of a global sample of 26 unrelated genetic females. We observe that genetic diversity in the PAR1 is ...
Female mammals inactivate one of the two X chromosomes in each somatic cell in order to balance the X-linked gene dosage between females and males (X chromosome inactivation, XCI). This process is mediated by non-coding RNA X inactive specific transcript (Xist). Here, I show that, when embryonic stem (ES) cells were cultured under undifferentiated condition, inducible Xist was sufficient to silence genes in vitro. Furthermore, the induced XCI was counteracted by the endogenous capability of X chromosome reactivation (XCR) in the pluripotent ES cells. Thus, perturbing XCR players should tip the balance towards stronger gene silencing effects. Using this experimental system, we show that shRNA knock- down of histone acetyltransferase Kat8 and its associated protein from Male Specific Lethal (MSL) complex, Msl2, significantly enhanced the gene silencing effect of induced XCI in undifferentiated ES cells. Interestingly, Kat8 and Msl2 are involved in Drosophila dosage compensation by up-regulating ...
Most X-linked conditions are recessive. This means in an individual with two X chromosomes (many females), both copies of a gene (in other terms., one for each X chromosome) will need to have a noticeable modification or mutation whereas in an individual with one X chromosome (many men), just one content of the gene will need to have a mutation. A lady with a mutation in a single content of a gene regarding the X chromosome is reported to be a carrier for an X-linked condition. A male having a mutation in a gene regarding the X chromosome is normally impacted using the condition. Because females have actually two copies for the X chromosome and men have actually just one X chromosome, X-linked diseases that are recessive more prevalent among men than females. Nevertheless, X-linked recessive conditions can take place in both men and women.. For X-linked recessive problems, an unaffected provider mom whos got a mutation in a gene in the X chromosome can transfer either the X chromosome using ...
To our knowledge, this is the first study of X chromosome compensatory expression upregulation in sheep. We conclude that X chromosome upregulation was present, but largely partial. Additionally, X chromosome upregulation in fetal organs was not affected by the different maternal diets. While a number of species, both invertebrates and vertebrates, have been examined for their X:A ratios, whether X expression is globally upregulated is still highly debated [reviewed in (Gu and Walters 2017)]. Recent studies in therian mammals, including the human, mouse, bovine, and non-human primates mostly support the partial X chromosome upregulation conclusion with X:A ratio being close to 1 (Gu and Walters 2017; Duan et al., 2016; Ka et al., 2016). Our findings here contribute to the consensus of partial X chromosome upregulation in a new species.. The estimation of X:A ratios differs when different gene subgroups and different tissues are analyzed, thus resulting in completely different conclusions over ...
X chromosome inactivation (XCI), which occurs only in female (XX) and not in male (XY) embryos, ensures dosage compensation of X‐linked genes between the sexes. The initial steps in XCI involve a counting process, which senses the X chromosomes/autosomes ratio and restricts XCI to female mouse embryos. Initiation of XCI in the embryo proper also includes the random choice of the active (Xa) and the inactive (Xi) Xs in each cell. The selected Xi becomes the target of a chromosome‐wide mechanism of transcriptional silencing, which constitutes an exciting paradigm for epigenetic regulations and confirms interest in the molecular dissection of the X‐inactivation centre (Xic), a locus on the X chromosome that contains the Xist gene and the elements involved in counting, choice and silencing.. The random form of XCI occurs around the time of implantation of the late female blastocyst, in the differentiating epiblast that derives from the inner cell mass (ICM) and that will give rise to the ...
In species with chromosomal sex determination, X chromosomes are predicted to evolve faster than autosomes because of positive selection on recessive alleles or weak purifying selection. We investigated X chromosome evolution in Stegodyphus spiders that differ in mating system, sex ratio, and population dynamics. We assigned scaffolds to X chromosomes and autosomes using a novel method based on flow cytometry of sperm cells and reduced representation sequencing. We estimated coding substitution patterns (dN/dS) in a subsocial outcrossing species (S. africanus) and its social inbreeding and female-biased sister species (S. mimosarum), and found evidence for faster-X evolution in both species. X chromosome-to-autosome diversity (piX/piA) ratios were estimated in multiple populations. The average piX/piA estimates of S. africanus (0.57 [95% CI: 0.55-0.60]) was lower than the neutral expectation of 0.75, consistent with more hitchhiking events on X-linked loci and/or a lower X chromosome mutation ...
Transfer of a normal Chinese hamster X chromosome (carried in a mouse A9 donor cell line) to a nickel-transformed Chinese hamster cell line with an Xq chromosome deletion resulted in senescense of these previously immortal cells. At early passages of the A9/CX donor cells, the hamster X chromosome was highly active, inducing senescence in 100% of the colonies obtained after its transfer into the nickel-transformed cells. However, senescence was reduced to 50% when Chinese hamster X chromosomes were transferred from later passage A9 cells. Full senescing activity of the intact hamster X chromosome was restored by treatment of the donor mouse cells with 5-azacytidine, which induced demethylation of DNA. These results suggest that a senescence gene or genes, which may be located on the Chinese hamster X chromosome, can be regulated by DNA methylation, and that escape from senescence and possibly loss of tumor suppressor gene activity can occur by epigenetic mechanisms. ...
HUMARA Assay is one of the most widely used methods to determine the clonal origin of a tumor. The method is based on X chromosome inactivation and it takes the advantage of having different methylation status of a gene called HUMARA (short for Human Androgen receptor) that is located on X chromosome. Considering the fact that once one X chromosome is inactivated in a cell, all other cells derived from it will have the same X chromosome inactivated, this approach becomes a great tool to differentiate a monoclonal population from a polyclonal one in a female tissue. HUMARA gene, in particular, has three important features that make it highly convenient for the purpose. 1-) The gene is located on X chromosome and it goes through inactivation by methylation in normal embryogenesis of a female infant. The fact that most-but not all-genes on X chromosome undergo inactivation, this feature becomes an important one. 2-) Human Androgen Receptor gene alleles have varying numbers of CAG repeats. Thus, ...
In humans, inheritance of X-linked recessive traits follows a unique pattern made up of three points. -The first is that affected fathers cannot pass x-linked recessive traits to their sons because fathers give Y chromosomes to their sons. This means that males affected by an x-linked recessive disorder inherited the responsible X chromosome from their mothers. Second, x-linked recessive traits are more commonly expressed in males than females.[2] This is due to the fact that males possess only a single X chromosome, and therefore require only one mutated X in order to be affected. Women possess two X chromosomes, and thus must receive two of the mutated recessive X chromosomes (one from each parent). A popular example showing this pattern of inheritance is that of the descendants of Queen Victoria and the blood disease hemophilia.[3] -The last pattern seen is that x-linked recessive traits tend to skip generations, meaning an affected grandfather will not have an affected son, but could have an ...
Newsroom.ucla.edu UCLA scientists have discovered one reason why autoimmune diseases are more prevalent in women than in men. While males inherit their mothers X chromosome and fathers Y chromosome, females inherit X chromosomes from both parents. New research, which shows differences in how each of those X chromosomes is regulated, suggests that the X chromosome that females get from their father may help to explain their more active immune system.
Background: The haplotypes of the X chromosome are accessible to direct count in males, whereas the diplotypes of the females may be inferred knowing the haplotype of their sons or fathers. Here, we investigated: 1) the possible large-scale haplotypic structure of the X chromosome in a Caucasian population sample, given the single-nucleotide polymorphism ( SNP) maps and genotypes provided by Illumina and Affimetrix for Genetic Analysis Workshop 14, and, 2) the performances of widely used programs in reconstructing haplotypes from population genotypic data, given their known distribution in a sample of unrelated individuals. Results: All possible unrelated mother-son pairs of Caucasian ancestry ( N = 104) were selected from the 143 families of the Collaborative Study on the Genetics of Alcoholism pedigree files, and the diplotypes of the mothers were inferred from the X chromosomes of their sons. The marker set included 313 SNPs at an average density of 0.47 Mb. Linkage disequilibrium between ...
Hello, Im sorry Im posting my question here, but I have no idea where the questions on the X chromosome lie. :rolleyes2::rolleyes2: I was just wondering how it was possible that I would not share any segment of the X chromosome with my grandmother? Its usual ? Yet I share 20% of my DNA with her, but nothing in the X chromosome, it seemed weird. If you have an explanation for me, I searched but I can not find anything. Thank you so much ! :heart:
So traits that have large additive genetic components are more easily changed by selection. The authors set out to investigate the genetic basis of gene expression level in Drosophila (for many genes measured on array) and how this differs between males and females. By a series of crosses, the authors find that many more genes show additive genetic variation in their expression level in males than in females, and that a number of these genes are found on the X chromosome (as well as on the autosomes). Now the X chromosome seems to be be the key to this difference in the form of genetic variation (and the authors conduct further experiments to show this). As males have only a single X chromosome there simply is not any dominance due to genetic variation on the X chromosome (at least not simple non-epistatic dominance). The genetic variation on the X chromosome in males mainly contributes to the additive genetic component of variation (as there is no second allele to cause dominance). So genes on ...
The figure shows that a paternal grandmother (PGM) is more closely related to her granddaughter because the granddaughter carries a more or less exact replica of one of her X Chromosomes (the blue X chromosome in the figure) while her grandson carries neither or her X Chromosomes. Theoretically, she should prefer her granddaughter to her grandson. The maternal grandmother (MGM) is equally related to grandson and granddaughter, so she should not show favoritism. The chromosomes with red and black parts result from recombination (crossover) during meiosis.. The mother has two X chromosomes herself, so the probability of the mother passing any specific X chromosome gene to either a boy or a girl child is likewise 0.5. Therefore, the probability of any specific X chromosome gene being passed on from a maternal grandmother to a grandchild is 0.25 (0.5 x 0.5). From the standpoint of the maternal grandmother, there is no difference between grandson and granddaughter in X-chromosome relatedness and, ...
In this study, we investigated whether XIST and 53BP1 expression, two potential markers of resistance to HD alkylating chemotherapy in BRCA1-deficient tumors identified in preclinical models (12, 13), could be used as predictive markers in breast cancer patients. We present early and preliminary evidence that high XIST expression or low 53BP1 expression could be used to identify BRCA1-like tumors that have early events and poorer outcome than BRCA1-like tumors that have low XIST and high 53BP1 expression.. The mechanism of loss of XIST expression seems to be through loss of the inactive X chromosome (12). We observed that the copy number profiles of some patients hinted at losing an X chromosome. However, we are unable to tell whether this is the inactive X chromosome and whether those without apparent loss may have copy number neutral DNA loss. These findings fit with the literature in which XIST expression, deregulation, and loss of the inactive X chromosome have been described in basal-like ...
A recent study in chimpanzees reported an excess of dN/dS compared with pN/pS on the X chromosome but not on autosomes [15]. This result was interpreted as the consequence of a higher rate of fixation of partial recessive beneficial alleles on the X chromosome, again a consequence of hemizygosity. To evaluate this result in humans, we computed the DoS statistic for each human chromosome. A positive value of the DoS (excess of dN/dS relative to pN/pS) is indicative of positive selection while a negative DoS reflects the influence of purifying selection. We report that the human X chromosome does indeed have a higher DoS than the autosomes (−0.134 versus −0.171 for X chromosome and median autosomes, respectively). Some autosomes have, however, a DoS very close to that of the X chromosome, for example, chromosome 21 (DoS = −0.129) and chromosome 14 (DoS = −0.139). Moreover, the confidence interval on DoS, estimated by bootstrapping genes within chromosomes (1000 replicates), was very large ...
The X chromosome is ane o the twa sex-determinin chromosomes (allosomes) in mony organisms, includin mammals (the ither is the Y chromosome), an is foind in bauth males an females. It is a pairt o the XY sex-determination seestem an X0 sex-determination seestem. The X chromosome wis named for its unique properties bi early researchers, that resultit in the namin o its coonterpairt Y chromosome, for the next letter in the alphabet, efter it wis diskivered later.[5] ...
The X chromosome of the Rehnia spinosus (Orthoptera) spermatocyte exists in a vesicle separate from the rest of the nucleus during its replication. This chromosome is typically heterochromatic, and late replicating. After replication the chromosome vesicle fuses with the nucleus. Cytophotometric determination of DNA and histone during replication of the chromosome revealed two types of histone. One class increases in amount in proportion to the DNA. The second class remains constant as DNA doubles, and probably increases later. Autoradiographic studies of incorporation of amino acids indicates that histone labelling occurs during chromosome replication. However, a lag in amino acid incorporation suggests that DNA replication in the X chromosome, while accompanied, or closely followed, by complexing with histone, is not necessarily coupled with its synthesis.. ...
The natural function of the XIST gene, located on the X chromosome, is to effectively silence one of the two X chromosomes in female cells, making expression of X-linked genes similar to that of men, who have just one X chromosome. The large XIST RNA is produced early in development from one of the females two X chromosomes, and this unique RNA then paints the X chromosome and modifies its structure so that its DNA cant be expressed to produce proteins and other components. This effectively renders most of the genes on the extra chromosome inactive.. Lawrence and colleague Lisa Hall PhD, research assistant professor of cell and developmental biology at UMMS, became motivated by the idea that this effect might be replicated in an extra chromosome 21 in trisomic cells and Jun Jiang, PhD, instructor of cell and developmental biology at UMMS, worked with Dr. Lawrence to begin a research project to insert the XIST gene into one chromosome 21 - supported by NIH funding for high-risk, high-impact ...
X-linked genes are found on the sex X chromosome. X-linked genes just like autosomal genes have both dominant and recessive types. Recessive X-linked disorders are rarely seen in females and usually only affect males. This is because males inherit their X chromosome and all X-linked genes will be inherited from the maternal side. Fathers only pass on their Y chromosome to their sons, so no X-linked traits will be inherited from father to son. Females express X-linked disorders when they are homozygous for the disorder and become carriers when they are heterozygous. An infamous recessive X-linked disorder is Hemophilia A. Hemophilia is a disorder where blood does not clot properly due to a shortage of clotting factor VIII. This disorder gained recognition as it traveled through royal families, notably the descendents of Britains Queen Victoria. X-linked dominant inheritance will show the same phenotype as a heterozygote and homozygote. Just like X-linked inheritance, there will be a lack of ...
XWAS: a software toolset for genetic data analysis and association studies of the X chromosome Feng Gao , Diana Chang , Arjun Biddanda , Li Ma , Yingjie Guo , Zilu Zhou , Alon Keinan doi: http://dx.doi.org/10.1101/009795 XWAS is a new software for the analysis of the X chromosome in association studies and similar studies.…
The X chromosome lives a genetic and genealogical life all of its own because of its unique inheritance properties which vary depending on whether you are a male and inherit the X only from your mother, or a female an inherit an X chromosome from both parents. Because of this, its a great, and often…
A UCLA study revealed that a gene on the X chromosome may help explain why more women than men develop multiple sclerosis and other autoimmune diseases. Researchers found that a gene known as Kdm6a was expressed more in womens immune cells than in mens, and expressed more in female mice than in males.
Chapel Hill, NC - In a study published this week, a group of scientists including University of North Carolina (UNC) biologist Dr. Jason Lieb, present experiments supporting a long-standing hypothesis that explains how males can survive with only one copy of the X chromosome. The finding provides clarity to a hotly debated topic in science…
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Chromosomes are long, threadlike structures of DNA. A male has one X and one Y sex chromosome, and a female has two X chromosomes. A sex-linked disorder is caused by a mutation in a gene on the X chromosome. As males only have one copy of each gene on the X chromosome, theyll be affected if one of those genes is mutated. As females have two copies of the X chromosome, theyre less likely to develop an X-linked condition, because the normal copy of the chromosome can usually cover for (mask) the altered version. Females can still be affected by X-linked disorders, but the condition is usually less severe than when the gene alteration is present in an affected male.. Types of MD inherited in this way include Duchenne MD and Becker MD, which is why these conditions are more common and more severe in males.. ...
Citation: N/A Interpretive Summary: Identification of genes accounting for significant effects on economically important traits ultimately requires alignment of the human and swine maps. Until now only a few genes have been mapped by linkage analysis on porcine chromosome X. Though the genes mapped to chromosome X are the same in such distinct species as human and mouse, the relative orders of genes are frequently quite different. Therefore to determine if the order of genes on the pig and human X chromosomes are the same we mapped four new genes to add to the five other genes previously mapped. Even after the addition of four genes to the porcine linkage map there is no evidence of rearrangements in gene order between porcine and human X chromosomes. Of newly mapped genes only TBG can be considered a possible candidate gene as it maps to the near proximity of QTL for fatness. Technical Abstract: For amplification of the porcine gene fragments amplification primers were designed from human gene ...
A study from a team of Massachusetts General Hospital (MGH) investigators points toward a potential strategy for treating X-linked disorders - those caused by mutations in the X chromosome - in females.
A study from a team of Massachusetts General Hospital (MGH) investigators points toward a potential strategy for treating X-linked disorders - those caused by mutations in the X chromosome - in females.
The most common form of EDMD is X-linked. This means that the changed gene is on the X chromosome. Chromosomes contain genes and are in the nucleus of your cells. Only boys get this form of EDMD. Girls have two X chromosomes, one from each parent. Boys get one X chromosome from their mother and a Y chromosome from their father. Because a boy only has 1 copy of the changed gene, a mutation means that he will not have enough of the protein to keep his muscles working well. A girl with the gene defect usually gets enough normal protein from her other X chromosome. But she will be a carrier for the mutation and can pass it on to her children.. ...
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March 23, 2016: If a woman has two X chromosomes, how do we know which X chromosome each of her offspring has? She received one X from her mother and one X from her father. Will her offspring receive the X from her mother or the X from her father? Is there a 50/50 chance of either? Or does it depend upon the offsprings sex- i.e. females receive X chromosome donated from grandmother, males receive X chromosome donated from grandfather? Do we know for sure ...
Illustration of an X chromosome. Chromosomes are a packaged form of the genetic material DNA, which condenses into chromosomes during cell replication for ease of division and transport into the new cell. Each chromosome consists of two identical strands (chromatids), aligned parallel to each other and joined at an area called a centromere. - Stock Image C027/7004
Durham N.C. The first comprehensive survey of gene activity in the X...The results may have important implications for understanding the diff...Willard said that the extensive variation in gene activity in the sex ... We looked at the X chromosomes of 40 women and every one of them had...Willard and study co-author Laura Carrel Ph.D. of Penn State report...,Variation,in,womens,X,chromosomes,may,explain,differences,among,individuals,,between,sexes,biological,biology news articles,biology news today,latest biology news,current biology news,biology newsletters
Scientists expose the X chromosomes complete genetic sequence. New research shows how the X and Y chromosomes evolved from a pair of regular chromosomes 300 million years ago.
ZCZC MIASPFAT3 ALL TTAA00 KNHC DDHHMM TROPICAL DEPRESSION EIGHTEEN PROBABILITIES NUMBER 2 NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 5 AM EDT SUN SEP 18 2005 PROBABILITIES FOR GUIDANCE IN HURRICANE PROTECTION PLANNING BY GOVERNMENT AND DISASTER OFFICIALS AT 5 AM EDT...0900Z...THE DEPRESSION CENTER WAS LOCATED NEAR LATITUDE 21.7 NORTH...LONGITUDE 71.2 WEST CHANCES OF CENTER OF THE DEPRESSION PASSING WITHIN 65 NAUTICAL MILES OF LISTED LOCATIONS THROUGH 2AM EDT WED SEP 21 2005 LOCATION A B C D E LOCATION A B C D E 22.8N 75.3W 44 X X X 44 COCOA BEACH FL X X 7 6 13 23.4N 77.5W 12 19 X 1 32 DAYTONA BEACH FL X X 2 7 9 23.8N 80.0W X 14 11 1 26 JACKSONVILLE FL X X X 5 5 MWCG 193N 814W X X 1 4 5 KEY WEST FL X 1 17 5 23 MUGM 200N 751W 3 1 X X 4 MARCO ISLAND FL X X 16 5 21 MUCM 214N 779W 5 11 1 1 18 FT MYERS FL X X 13 7 20 MUCF 221N 805W X 6 10 2 18 VENICE FL X X 8 10 18 MUSN 216N 826W X X 5 9 14 TAMPA FL X X 4 11 15 MUHA 230N 824W X X 12 7 19 CEDAR KEY FL X X 1 10 11 MUAN 219N 850W X X 1 10 11 ST MARKS FL ...
A mode of inheritance in which a mutation in a gene on the X chromosome causes the phenotype to be expressed in males who are hemizygous for the gene mutation (i.e., they have only one X chromosome) and in females who are homozygous for the gene mutation (i.e., they have a copy of the gene mutation on each of their two X chromosomes). Carrier females who have only one copy of the mutation do not usually express the phenotype, although differences in X-chromosome inactivation can lead to varying degrees of clinical expression in carrier females ...
This weeks Nature has a picture of the X chromosome on the cover. The issue has two articles on the topic. The first contains an analysis of the recently completed sequence. As I wrote before on the Y chromosome, women have two copies of the X. Previously, it had been thought that one was suppressed…
The X chromosome carries around 2000 genes and makes up about 5% of the total DNA in women and 2.5% in men. Alterations or mutations of these genes leads to disorders that are termed X-linked diseases.
Randomly, one of two X/X chromosomes is deactivated {for gene balancing (males have only one X chromosome )}. Because one X comes from mother and one from father, they may have different alleles. Thus, a clone of tissue produced from ancestral cell with, say, fathers deactivated X chromosome will have different genotype than a clone produced from the ancestral cell with deactivated mothers X chromosome ...
The addition of a chemical tag on an RNA molecule is the critical switch that inactivates one X chromosome in every cell, ensuring healthy development in all female mammals, according to new research by Weill Cornell Medicine ...
The human X chromosome has a unique biology that was shaped by its evolution as the sex chromosome shared by males and females. We have determined 99.3% of the euchromatic sequence of the X chromosome. Our analysis illustrates the autosomal origin of the mammalian sex chromosomes, the stepwise... mehr ...
A few days ago I discussed a new paper which explores the patterns of natural selection in the genome of the X chromosome. As you know the X is carried disproportionately by females, as males have only one copy, so it offers up an interesting window into evolutionary dynamics (see The Red Queen for a popular treatment).
This course will explore a diverse collection of striking biological phenomena associated with the X chromosome. We will examine the genetic basis and