Chromosome X News and Research

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The X chromosome is one of the two sex chromosomes in humans (the other is the Y chromosome). The sex chromosomes form one of the 23 pairs of human chromosomes in each cell. The X chromosome spans about 155 million base pairs (the building blocks of DNA) and represents approximately 5 percent of the total DNA in cells.

Each person normally has one pair of sex chromosomes in each cell. Females have two X chromosomes, while males have one X and one Y chromosome. Early in embryonic development in females, one of the two X chromosomes is randomly and permanently inactivated in somatic cells (cells other than egg and sperm cells). This phenomenon is called X-inactivation or Lyonization. X-inactivation ensures that females, like males, have one functional copy of the X chromosome in each body cell. Because X-inactivation is random, in normal females the X chromosome inherited from the mother is active in some cells, and the X chromosome inherited from the father is active in other cells.

Some genes on the X chromosome escape X-inactivation. These genes are located at the tip of the short (p) arm of the X chromosome in an area known as the pseudoautosomal region. Although many genes are unique to the X or Y chromosome, genes in the pseudoautosomal region are present on both chromosomes. As a result, men and women each have two functional copies of these genes. Many genes in the pseudoautosomal region are essential for normal development.

Identifying genes on each chromosome is an active area of genetic research. Because researchers use different approaches to predict the number of genes on each chromosome, the estimated number of genes varies. The X chromosome likely contains between 900 and 1,400 genes.

Genes on the X chromosome are among the estimated 20,000 to 25,000 total genes in the human genome.

Johnson & Johnson's sales increase 5.1% to $18.5 billion in Q3 2014

Johnson & Johnson today announced sales of $18.5 billion for the third quarter of 2014, an increase of 5.1% as compared to the third quarter of 2013. Operational results increased 5.8% and the negative impact of currency was 0.7%. Domestic sales increased 11.6%. International sales decreased 0.3%, reflecting operational growth of 1.0% and a negative currency impact of 1.3%.

14 Oct 2014

Researchers discover mitochondrial and nuclear tRNA-lookalikes in human genome

Transfer RNAs (tRNAs) are ancient workhorse molecules and part of the cellular process that creates the proteins, critical building blocks of life that keep a cell running smoothly.

9 Oct 2014

New study reveals mechanism that compromises chromosome stability

During cell division, chromosomes acquire a characteristic X-shape with the two DNA molecules (sister chromatids) linked at a central "connection region" that contains highly compacted DNA.

9 Oct 2014

Researchers identify biomarker that can predict GS7 prostate cancer patients

Researchers at The University of Texas MD Anderson Cancer Center have identified a biomarker living next door to the KLK3 gene that can predict which GS7 prostate cancer patients will have a more aggressive form of cancer.

3 Oct 2014

Researchers uncover molecular interaction between key proteins in cell division

Researchers from Guillermo Montoya's team at the Spanish National Cancer Research Centre (CNIO), in collaboration with Isabelle Vernos' Group from the Centre for Genomic Regulation (CRG), have uncovered the molecular interaction between TACC3 and chTOG, key proteins in forming the internal cellular framework that enables and sustains cell division.

30 Sep 2014

Novel treatment makes life-saving difference to young patients with Ph-like ALL

St. Jude Children's Research Hospital investigators found that adjusting treatment based on early response to chemotherapy made a life-saving difference to young patients with an acute lymphoblastic leukemia (ALL) subtype associated with a poor outcome.

24 Sep 2014

Researchers explore gene expression in normal vestibular nerves, vestibular schwannomas

Researchers from the University of Toronto, directed by Drs. Gelareh Zadeh and Boris Krischek, investigated gene expression in normal vestibular nerves and vestibular schwannomas (VSs).

24 Sep 2014

MIT engineers find new strategy to combat superbugs

In recent years, new strains of bacteria have emerged that resist even the most powerful antibiotics. Each year, these superbugs, including drug-resistant forms of tuberculosis and staphylococcus, infect more than 2 million people nationwide, and kill at least 23,000. Despite the urgent need for new treatments, scientists have discovered very few new classes of antibiotics in the past decade.

22 Sep 2014

Research findings provide more details about earliest stages of neurodegenerative disease

The link between a protein typically associated with Alzheimer's disease and its impact on memory and cognition may not be as clear as once thought, according to a new study from the University of Wisconsin-Madison's Waisman Center.

19 Sep 2014

Jacobsen syndrome linked to autism, find UCSD and SDSU researchers

A rare genetic disorder known as Jacobsen syndrome has been linked with autism, according to a recent joint investigation by researchers at San Diego State University and the University of California, San Diego. In addition to suggesting better treatment options for people with Jacobsen syndrome, the finding also offers more clues into the genetic underpinnings of autism.

18 Sep 2014

Study uncovers new genetic risk factor for deadly skin cancer

Buffers that guard against damage to the ends of chromosomes could hold the key to a better understanding of malignant melanoma - the deadliest form of skin cancer - according to new research from the University of Leeds.

18 Sep 2014

Reproductive cell division has mechanical safeguard against chromosome sorting errors

Reproductive cell division has evolved a simple, mechanical solution to avoid chromosome sorting errors, researchers report in the Sept. 11 Science Express.

17 Sep 2014

New project aims at delivering innovative test to improve safety of chemical products, drugs

The Genotrace project, combining targeted research and technology transfer, aims at delivering an innovative test to improve the safety of chemical products, drugs, human and animal food and the environment.

10 Sep 2014

Researchers identify non-protein-coding RNA whose expression linked to ovarian cancer

Over the years researchers have made tremendous strides in the understanding and treatment of cancer by searching genomes for links between genetic alterations and disease.

10 Sep 2014

Researchers unravel molecular mechanism of mRNA recognition

The information encoded in our genes is translated into proteins, which ultimately mediate biological functions in an organism.

9 Sep 2014

DNA regions that contained telomeres generate RNAs

RNA is one of the most primitive molecules associated with life that has awakened most interest over the last decade; a sister molecule to cellular DNA from which it originates via a process called transcription.

4 Sep 2014

Researchers reveal how alteration of single nucleotide could initiate fragile X syndrome

Researchers reveal how the alteration of a single nucleotide—the basic building block of DNA—could initiate fragile X syndrome, the most common inherited form of intellectual disability. The study appears in The Journal of Cell Biology.

2 Sep 2014

Minnesota researchers develop animal research model for FSHD

Researchers at the University of Minnesota have developed an animal research model for facioscapulohumeral muscular dystrophy (FSHD) to be used for muscle regeneration research as well as studies of the effectiveness of potential therapies for FSHD.

29 Aug 2014

Study examines national impact of newborn screening test for SCID

Severe combined immunodeficiency (SCID), a potentially life-threatening, but treatable, disorder affecting infants, is twice as common as previously believed, according to a new study that is the first to examine the national impact of this newborn screening test.

20 Aug 2014

Hippo pathway identifies and prevents progression of abnormal cells into cancer

Researchers from Boston University School of Medicine report that a tumor suppressor pathway, called the Hippo pathway, is responsible for sensing abnormal chromosome numbers in cells and triggering cell cycle arrest, thus preventing progression into cancer.

16 Aug 2014