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.

Major breakthrough in understanding how malaria parasite grows and multiplies

Scientists have made a major breakthrough in understanding how the parasite that causes malaria is able to multiply at such an alarming rate, which could be a vital clue in discovering how it has evolved, and how it can be stopped.

11 Feb 2020

New mechanism for repair of chromosomal breaks

Chromosomal breaks are the most harmful damage for cells. If they are not repaired, they block the duplication and segregation of chromosomes, stop the growth cycle and cause cell death. These breaks appear frequently in tumor cells and are produced spontaneously during the replication of genetic material.

10 Feb 2020

Growing eggs and sperm to treat infertility

Scientists at the University of California, Los Angeles, have reported, in the journal Cell Reports, the mechanism of how the very early precursor or stem cells which eventually give rise to the germ cells, eggs and sperm, are formed over the course of development. This could help create eggs and sperms under laboratory conditions to help infertile people who don’t have sperms, or eggs, for instance.

9 Feb 2020

Discovery of potential cause of age-related macular degeneration

Age related macular degeneration or AMD leads to loss of vision in around 1.5 million people in the United Kingdom and millions of others around the world. In a new study researchers have discovered a new protein that could explain the causation and thus provide clues to its early diagnosis and effective treatment. The study was published in the latest issue of the journal Nature Communications.

9 Feb 2020

Research provides new insights into molecular basis of X-chromosome inactivation

Researchers at the European Molecular Biology Laboratory in Heidelberg and Institut Curie in Paris have shown that the protein SPEN plays a crucial role in the process of X-chromosome inactivation, whereby female mammalian embryos silence gene expression on one of their two X chromosomes.

7 Feb 2020

Natural antioxidant reverses reproductive harms caused by BPA exposure in worms

From plastics to pesticides, it seems like every week delivers fresh news about the dangers of endocrine disruptors--chemicals in the environment that alter the body's hormones and can lead to reproductive, developmental, neurologic and immune problems and cancer.

6 Feb 2020

Researchers discover new mutational phenomenon chromothripsis in cancer

Researchers at Harvard Medical School and EMBL-EBI have carried out the largest analysis across cancer types of the newly discovered mutational phenomenon chromothripsis.

6 Feb 2020

Cancer mutations may arise decades before diagnosis

Researchers at EMBL's European Bioinformatics Institute and the Francis Crick Institute have analyzed the whole genomes of over 2600 tumors from 38 different cancer types to determine the chronology of genomic changes during cancer development.

5 Feb 2020

Developing tests for genetic signs could lead to earlier cancer detection

Early signs of cancer can appear years before diagnosis and developing tests for these genetic signs could provide new ways to spot cancer early, according to new research led by the Crick and EMBL-EBI, and supported by an international cancer genomics consortium, the Pan-Cancer Analysis of Whole Genomes Project.

4 Feb 2020

Coronavirus could spread explosively, tight control needed

The coronavirus may be taking a higher toll of life than we thought, say scientists, in a new study published on January 30, 2020, in The Lancet. But another startling new study based on mathematical modeling, published in the same journal, predicts that almost 76,000 people may have acquired the infection in Wuhan city, and that multiple epidemics in major connected cities inside and outside China may already be brewing. Yet the death rate is markedly low, in this case.

3 Feb 2020

Daily alcohol consumption ages brain

There are several studies looking at the effects of alcohol intake on the brain. Anew study adds to the existing knowledge. The large study with around 11,651 participants from United Kingdom shows that each gram of alcohol consumed could lead to around a week of aging of the brain.

2 Feb 2020

Research opens the door to healthier white bread

Group identifies the parts of the wheat genome that control fiber content of white flour – raises hope that products will be in supermarkets within five years.

31 Jan 2020

Successful gene therapy trial in patients with X-linked Chronic Septic Granulomatosis

American and British teams led by Drs Kohn (University of California, Los Angeles), Malech (NIH), Williams (Boston Children's) and Trasher (Great Ormond Street Institute of Child Health) published yesterday in Nature Medicine the conclusive results of a gene therapy trial conducted in the United States and Great Britain in 9 patients with X-linked Chronic Septic Granulomatosis (X-CGD), a rare and severe immune dysfunction. Six of them are free of treatment for complications generated by the disease.

28 Jan 2020

New gene correction therapy for hereditary muscular disease among children

Duchenne type muscular dystrophy is the most common hereditary muscular disease among children, leaving them wheelchair-bound before the age of twelve and reducing life expectancy.

27 Jan 2020

Healing and hope for families affected by fragile X in Eastern Europe

Mothers and fathers and their young children crowded into an old, government-run children's hospital in Belgrade, Serbia, colorful, cartoonish drawings covering its hallway walls. Parents struggled to soothe their anxious, wriggly boys and girls. But they were patient, polite. It was, after all, a day unlike any other. A day for hope.

23 Jan 2020

New discovery changes the understanding of gene expression

A group of University of Chicago scientists has uncovered a previously unknown way that our genes are made into reality.

22 Jan 2020

Oldest African DNA on record shines light on the deep human past

A team of international researchers, which includes a Saint Louis University Madrid anthropologist, dug deep to find some of the oldest African DNA on record, in a new study published in Nature.

22 Jan 2020

First randomized clinical trial compares targeted therapies for acute lymphoblastic leukemia

Researchers from St. Jude Children's Research Hospital and the Chinese Children's Cancer Group led the first randomized, Phase III clinical trial comparing targeted therapies for acute lymphoblastic leukemia (ALL) driven by the Philadelphia chromosome.

17 Jan 2020

3D structure of DNA is 'rewired' in hormone-resistant ER+ breast cancers

Epigenetic changes occur in the DNA of breast cancer cells that have developed a resistance to hormone therapy, an effective treatment for ER+ breast cancer, which accounts for 70% of all diagnoses.

16 Jan 2020

Princeton researchers uncover vital role played by a protein elevated in many cancers

Researchers at Princeton University have successfully recreated a key process involved in cell division in a test tube, uncovering the vital role played by a protein that is elevated in over 25% of all cancers.

14 Jan 2020