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.
Human genome sequenced in its entirety for the first time

Human genome sequenced in its entirety for the first time

What does the future look like for bleeding disorders?

What does the future look like for bleeding disorders?

New study uncovers a mechanism of sleep in zebrafish

New study uncovers a mechanism of sleep in zebrafish

Study underscores why COVID-19 vaccine boosters are important for all adults

Study underscores why COVID-19 vaccine boosters are important for all adults

Researchers identify never-before-defined subtypes of a blood cancer

Researchers identify never-before-defined subtypes of a blood cancer

Scientists identify new gene that contributes to type 1 diabetes progression

Scientists identify new gene that contributes to type 1 diabetes progression

Scientists discover gene responsible for doubling the risk of respiratory failure from COVID-19

Scientists discover gene responsible for doubling the risk of respiratory failure from COVID-19

Identification of a candidate effector gene at COVID-19 risk locus

Identification of a candidate effector gene at COVID-19 risk locus

Chromosome aberrations linked to acute toxicities in esophageal cancer patients

Chromosome aberrations linked to acute toxicities in esophageal cancer patients

New application makes it possible to monitor the symptoms of people at risk for psychosis

New application makes it possible to monitor the symptoms of people at risk for psychosis

Rutgers study links genetic disorders to walking patterns

Rutgers study links genetic disorders to walking patterns

Research reveals the mechanisms of cardiac sex disparities at an early stage

Research reveals the mechanisms of cardiac sex disparities at an early stage

Researchers reveal the mechanism of artificial chromosome formation in C. elegans' embryos

Researchers reveal the mechanism of artificial chromosome formation in C. elegans' embryos

Factors contributing to a weak antibody response to the Pfizer COVID-19 vaccine

Factors contributing to a weak antibody response to the Pfizer COVID-19 vaccine

Famous scientist joins NYU Langone’s Division of Rheumatology

Famous scientist joins NYU Langone’s Division of Rheumatology

Devastating genetic disease in children may be treatable in adulthood

Devastating genetic disease in children may be treatable in adulthood

Qatar genomics study reveals key historical and social insights into Arab populations

Qatar genomics study reveals key historical and social insights into Arab populations

New metagenome assembler can generate accurate DNA sequences

New metagenome assembler can generate accurate DNA sequences

NIH awards more than $8 million to support seven high-risk, high-reward projects at Penn Medicine

NIH awards more than $8 million to support seven high-risk, high-reward projects at Penn Medicine

New Maternal and Child Health Research Institute launched to improve national health in Singapore

New Maternal and Child Health Research Institute launched to improve national health in Singapore