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.
Researchers have pinpointed specific gene and protein over-production in metastatic melanoma

Researchers have pinpointed specific gene and protein over-production in metastatic melanoma

Researchers discover genetically controlled brain mechanism responsible for social behavior in humans

Researchers discover genetically controlled brain mechanism responsible for social behavior in humans

Changes to prenatal genetic testing could mean more babies born with abnornalities

Changes to prenatal genetic testing could mean more babies born with abnornalities

Birth abnormality rates could increase if proposed changes to prenatal testing go ahead

Birth abnormality rates could increase if proposed changes to prenatal testing go ahead

New initiative to provide $600k to fund new research into Down Syndrome

New initiative to provide $600k to fund new research into Down Syndrome

Exercise helps find genetic regions linked to prediabetes

Exercise helps find genetic regions linked to prediabetes

New clues about the location of genes potentially involved in the most common type of lung cancer

New clues about the location of genes potentially involved in the most common type of lung cancer

Technique called phylogenetic footprinting reveals new gene regulation system

Technique called phylogenetic footprinting reveals new gene regulation system

Foxp2 gene plays an essential role in the development of social communication

Foxp2 gene plays an essential role in the development of social communication

Early embryos with abnormal chromosomes are capable of returning to normal when grown in culture in the laboratory

Early embryos with abnormal chromosomes are capable of returning to normal when grown in culture in the laboratory

Scientists have tracked down the biological trigger that gives rise to Van Buchem disease

Scientists have tracked down the biological trigger that gives rise to Van Buchem disease

Research challenges the evolutionary paradigm that continuous alterations occur during the course of genome evolution

Research challenges the evolutionary paradigm that continuous alterations occur during the course of genome evolution

MicroRNAs play an important role in human cancer

MicroRNAs play an important role in human cancer

Researchers link aberrant 'microRNA' expression to human cancer

Researchers link aberrant 'microRNA' expression to human cancer

New understanding of microRNAs

New understanding of microRNAs

Study is the first to identify involvement of chromosome 21 in developmental regression autism

Study is the first to identify involvement of chromosome 21 in developmental regression autism

Computer simulation helps understand DNA transcription process

Computer simulation helps understand DNA transcription process

Scientists have uncovered the structure of a network of proteins that help regulate the life cycle of cells

Scientists have uncovered the structure of a network of proteins that help regulate the life cycle of cells

The bacteria that cause food poisoning, bubonic plague, and whooping cough all deploy the same weapon to infect the body

The bacteria that cause food poisoning, bubonic plague, and whooping cough all deploy the same weapon to infect the body

Bald men can blame mum!

Bald men can blame mum!