Chromosome X News and Research

RSS

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.

Longer looks: Former Komen VP's new 'bona fides'; Alzheimer's definition changing?; Palin on her special needs child

Even if you put politics and ideology completely aside, Karen Handel had to resign from Susan G. Komen for the Cure. It's hard to think of the last time an employee did so much damage to such a respected brand in so little time. ... But while Komen will sustain long-term damage, Handel probably will be just fine. Yes, she's lost her position as Komen's vice president for public policy. But Handel has long had political aspirations, and she's now a right-wing cause célèbre.

10 Feb 2012

Mental illness suspect genes are among the most environmentally responsive regulatory mechanisms

For the first time, scientists have tracked the activity, across the lifespan, of an environmentally responsive regulatory mechanism that turns genes on and off in the brain's executive hub.

3 Feb 2012

DNA-based prenatal blood test can also identify trisomy 13 and 18

A newly available DNA-based prenatal blood test that can identify a pregnancy with Down syndrome can also identify two additional chromosome abnormalities: trisomy 18 (Edwards syndrome) and trisomy 13 (Patau syndrome). The test for all three defects can be offered as early as 10 weeks of pregnancy to women who have been identified as being at high risk for these abnormalities.

3 Feb 2012

Cancer Genomics now available online

Genome Research publishes online and in print today a special issue entitled, "Cancer Genomics," highlighting insights gained form cutting-edge genomic and epigenomic analyses of cancer.

2 Feb 2012

Novartis' Gleevec receives FDA approval for use in patients with CD117-positive GIST

The U.S. Food and Drug Administration today granted Gleevec (imatinib) regular approval for use in adult patients following surgical removal of CD117-positive gastrointestinal stromal tumors.

1 Feb 2012

Newly discovered molecular pathway may explain how AML develops

Researchers at UC Santa Barbara have discovered a molecular pathway that may explain how a particularly deadly form of cancer develops. The discovery may lead to new cancer therapies that reprogram cells instead of killing them. The findings are published in a recent paper in the Journal of Biological Chemistry.

30 Jan 2012

Research Down Syndrome enters second year of national running program

Research Down Syndrome (RDS), a nonprofit foundation that is among the leading sources for funding of Down syndrome related cognitive research, is entering the second year of its national running program, Race for the Extraordinary, to help increase public awareness and funding for Down syndrome research. The mission of RDS is the development of safe and effective therapies to address the intellectual difficulties associated with Down syndrome.

30 Jan 2012

Chromosome aberrations happen in pairs when it comes to cancer

A healthy genome is characterized by 23 pairs of chromosomes, and even a small change in this structure - such as an extra copy of a single chromosome - can lead to severe physical impairment. So it's no surprise that when it comes to cancer, chromosomal structure is frequently a contributing factor, says Prof. Ron Shamir of the Blavatnik School of Computer Science at Tel Aviv University.

24 Jan 2012

MSC-mediated RNAi transfer holds promise for Huntington's disease

A team of researchers at the UC Davis Institute for Regenerative Cures has developed a technique for using stem cells to deliver therapy that specifically targets the genetic abnormality found in Huntington's disease, a hereditary brain disorder that causes progressive uncontrolled movements, dementia and death.

20 Jan 2012

Inherited mutation links exploding chromosomes to cancer

An inherited mutation in a gene known as the guardian of the genome is likely the link between exploding chromosomes and some particularly aggressive types of cancer, scientists at the European Molecular Biology Laboratory (EMBL), the German Cancer Research Centre (DKFZ) and the University Hospital, all in Heidelberg, Germany, have discovered.

20 Jan 2012

Researchers reveal role of micronuclei in cancer process

They are the Robinson Crusoes of the intracellular world -- lone chromosomes, whole and hardy, stranded outside the nucleus where their fellow chromosomes reside. Such castaways, each confined to its own "micronucleus," are often found in cancer cells, but scientists haven't known what role, if any, they play in the cancer process.

20 Jan 2012

Earlier detection of Fragile X syndrome made possible

Now families children with fragile X syndrome may have a chance of earlier detection and intervention. The Murdoch Children's Research Institute breakthrough could allow newborn screening of the world's most common cause of inherited developmental disability. The research findings were published in the journal Clinical Chemistry.

19 Jan 2012

Novel technique accurately maps gene-regulation proteins

A novel technique has been developed and demonstrated at Penn State University to map the proteins that read and regulate chromosomes -- the string-like structures inside cells that carry genes.

19 Jan 2012

GSA honors researchers, educators for distinguished service in the field of genetics

The Genetics Society of America (GSA) is pleased to announce the 2012 recipients of its five awards for distinguished service in the field of genetics. The recipients of these awards were nominated and selected by their colleagues.

19 Jan 2012

Source of infantile epilepsy found in a gene

Researchers from Adelaide have discovered a 20-year mystery about a type of epilepsy in infants. It is caused by a single mutation in one gene they found. The discovery will allow for better screening, diagnosis and prediction of the risk of seizures for sufferers of benign familial infantile epilepsy, the researchers say.

16 Jan 2012

NimbleGen Sequence Capture 385K array identifies gene mutations linked with hereditary hearing loss

Hereditary hearing loss is the most common sensory disorder in humans. A German research team led by Ingo Kurth from the Institute of Human Genetics at the University Hospital Jena, Germany, used a number of different methods, including Roche's NimbleGen Custom Sequence Capture 385K array to identify the gene mutated in the disease locus of the X-chromosome of a Spanish family with hereditary hearing loss.

13 Jan 2012

Scientists identify rare genetic mutation linked to prostate cancer

After a 20-year quest to find a genetic driver for prostate cancer that strikes men at younger ages and runs in families, researchers have identified a rare, inherited mutation linked to a significantly higher risk of the disease.

12 Jan 2012

DNA may be used to predict lifespan: Study

Researchers may soon be able to predict how long a person will live based on their genetics. This could result from the discovery by a University of Glasgow team in Scotland showing that telomere length on the ends of DNA in their genes in early-life predicts life spans.

11 Jan 2012

New imaging technology may pinpoint subtle aberrations in molecular biosignature of cancer

Despite advances in both the diagnosis and treatment of breast cancer, the disease remains a leading worldwide health concern.

6 Jan 2012

Researchers identify candidate genes for histiocytoid cardiomyopathy

Researchers are closing in on a rare genetic disorder causing a heart condition in infants. Histiocytoid cardiomyopathy (HC) often causes sudden death before a child reaches 2 years of age. Gene analysis is helping to narrow the many theories surrounding the genetic basis of HC.

4 Jan 2012