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.

Largest "gene deserts" yet discovered in the human genome sequence

A detailed analysis of chromosomes 2 and 4 has detected the largest "gene deserts" known in the human genome and uncovered more evidence that human chromosome 2 arose from the fusion of two ancestral ape chromosomes, researchers supported by the National Human Genome Research Institute (NHGRI).

6 Apr 2005

Method of gene therapy accurately corrects mutations in disease-causing genes

Harnessing the strength of a natural process that repairs damage to the human genome, a researcher from UT Southwestern Medical Center has helped establish a method of gene therapy that can accurately and permanently correct mutations in disease-causing genes.

5 Apr 2005

Method of gene therapy that can accurately and permanently correct mutations in disease-causing genes

4 Apr 2005

Mutations in the HFE gene directly associated with chronic joint disease

Mutations in the HFE gene, which is involved in iron regulation, seem to be directly associated with chronic joint disease (or haemophilic arthropathy) among haemophilic patients, claim a team of Portuguese scientists in the April issue of the journal Blood.

4 Apr 2005

Location on chromosome 2 that may contain one or more genes that contribute to dyslexia

Researchers trying to tease out the genetic basis of dyslexia have discovered a location on chromosome 2 that may contain one or more genes that contribute to the reading disorder and make it difficult for people to rapidly pronounce pseudowords.

3 Apr 2005

Dozens of new genes identified in X chromosome

By intensely and systematically comparing the human X chromosome to genetic information from chimpanzees, rats and mice, a team of scientists from the United States and India has uncovered dozens of new genes, many of which are located in regions of the chromosome already tied to disease.

3 Apr 2005

SERPINE2 identified as novel candidate gene for COPD susceptibility

Using a combination of genetic linkage, microarray gene expression and genetic association studies, a group of Brigham and Women’s Hospital/ Harvard Medical School researchers have identified a serine protease inhibitor clade E, member 2, or SERPINE2, “as a novel candidate susceptibility gene for COPD,” according to Sorachai Srisuma

3 Apr 2005

Urine actually helps a particular yeast stick to cells along the urinary tract

The finding might offer a new way to prevent or treat certain yeast and fungal infections, and the researchers' work also provides an unexpected new role for some proteins already known to help hungry yeast live longer.

30 Mar 2005

Protein Mnd2 protects chromosome bonds

The protein Mnd2 inhibits premature separation of chromosomes during the formation of gametes. The now published discovery of this regulatory function may help to understand the origin of some common congenital chromosome defects.

30 Mar 2005

Gene named ATBF1 may contribute to the development of prostate cancer

A gene named ATBF1 may contribute to the development of prostate cancer through acquired mutations and/or loss of expression, according to research at Emory University School of Medicine and its Winship Cancer Institute.

23 Mar 2005

X-Chromosome has the big story!!

The human genome is said by some to be the "book of life," and the X-chromosome a large part of the the plot. A team of genome researchers have described the nature of this mysterious "chapter" in the DNA story.

17 Mar 2005

Neuronal death and processing of Tau protein in Alzheimer’s Disease (AD)

In a research report recently published in the Journal of Alzheimer's Disease, published by IOS Press, a research group from the International School for Advanced Studies (ISAS\SISSA) in Trieste (Luisa Fasulo, Gabriele Ugolini e Antonino Cattaneo) showed that a processed form of tau protein induces neuronal death by apoptosis (programmed cell death) when expressed in cultured rat hippocampal neurons.

15 Mar 2005

Gene identified that confers susceptibility to age-related macular degeneration

By combining the tools of high-throughput biology and statistical genetics, scientists at Rockefeller University, Yale University School of Public Health and the National Eye Institute have identified a gene that confers susceptibility to age-related macular degeneration (AMD), the most common cause of vision loss in the United Sates for those over 60.

14 Mar 2005

DNA weak links may provide clues to cancer biology

The chromosomes of mammals, including humans, contain regions that are particularly prone to breaking under conditions of stress and in cancer. Now, new research by geneticists at Duke University Medical Center finds that yeast cells also contain such weak links in DNA and begins to reveal the molecular characteristics of these links that might help to explain them.

13 Mar 2005

Gene for AMD has now been identified by researchers

Age-related macular degeneration (AMD) is a debilitating eye disease affecting about 15 million people in the United States.

13 Mar 2005

Mouse gene shows new mechanism behind cardiac infarction in man

A gene that, in different variants, increases or decreases the level of atherosclerosis has been identified in mice. The corresponding human gene has been shown to play a role in the development of myocardial infarction.

9 Mar 2005

Abnormal brain structure tied to spatial, numerical thinking problems when children lack part of chromosome

Certain genetic diseases affect children's educational abilities in a distinctive pattern: impairing their numerical abilities more than their verbal skills. New research sheds light on this split in abilities by investigating how differences in brain structures may influence how the mind works.

3 Mar 2005

Gene variant that may increase the risk of late-onset Alzheimer's disease

Researchers from the MassGeneral Institute for Neurodegenerative Disorders (MIND) have identified a gene variant that may increase the risk of late-onset Alzheimer's disease.

2 Mar 2005

Scientists gain new insight into DiGeorge syndrome

A collaboration of European scientists has uncovered new insight into the most common chromosomal microdeletion syndrome in humans.

28 Feb 2005

Methylphenidate linked to chromosomal changes

In a small but startling preliminary new study, Texas researchers have found that after just three months, every one of a dozen children treated for attention deficit/hyperactivity disorder (ADHD) with the drug methylphenidate experienced a threefold increase in levels of chromosome abnormalities—occurrences associated with increased risks of cancer and other adverse health effects.

27 Feb 2005