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.

Ancient DNA reveals first prehistoric cases of Turner and Jacob's syndromes

Ancient DNA reveals first prehistoric cases of Turner and Jacob's syndromes, with new technique enhancing chromosome analysis

13 Jan 2024

Key gene linked to male bias in autism, Tourette's, and ADHD uncovered

Sex bias in attention deficit hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and Tourette syndrome (TS).

8 Dec 2023

New study provides insights about mosaic chromosomal alterations in diverse populations

As people age, the DNA in their cells begins to accumulate genetic mutations. Mosaic chromosomal alterations (mCAs), a category of mutations acquired in blood cells, are linked with a 10-fold increased risk of developing blood cancer.

1 Nov 2023

Copy number profiling provides insight as to why prostate cancer may become lethal

Researchers performed genome-wide copy number profiling of the androgen receptor (AR) on metastases from deceased prostate cancer patients.

16 Aug 2023

Simple blood tests for telomeric protein could provide a valuable screen for certain cancers

Once thought incapable of encoding proteins due to their simple monotonous repetitions of DNA, tiny telomeres at the tips of our chromosomes seem to hold a potent biological function that's potentially relevant to our understanding of cancer and aging.

21 Feb 2023

Pathological significance of CEACAMS 1, 5, and 6 in cancer biology, immunology and inflammatory disease

A new review was published in Genes & Cancer on February 1, 2023, entitled, "CEACAMS 1, 5, and 6 in disease and cancer: interactions with pathogens."

10 Feb 2023

3D architecture ofAedes aegypti’s chromosomes may offer clues on gene expression, regulation

When it comes to DNA, one pesky mosquito turns out to be a rebel among species.

9 Feb 2023

New blood test can detect prostate cancer with greater accuracy than current methods

Researchers at the University of East Anglia have helped develop a new blood test to detect prostate cancer with greater accuracy than current methods.

8 Feb 2023

Microscopic technique enables real-time study of RNA G-quadruplexes in living cells

A new microscopic technique allows for the real-time study of RNA G-quadruplexes in living cells, with implications for the fight against amyotrophic lateral sclerosis.

2 Feb 2023

Study identifies the DNA roots of resistance to targeted cancer therapy

A new clinical and preclinical study from UCLA Jonsson Comprehensive Cancer Center identifies the DNA roots of resistance to targeted cancer therapy, providing a possible strategy to address a vexing issue in cancer therapeutics.

26 Jan 2023

Persistent tumor mutation burden linked with therapeutic response to immunotherapy

Cancer experts have tried, sometimes unsuccessfully, to use the total number of mutations in a tumor, called the tumor mutation burden (TMB), to predict a patient's response to immunotherapy.

26 Jan 2023

Cryo-electron microscopy reveals detailed blueprint of viral genome replication machinery

RNA viruses, such as the coronavirus that causes COVID-19, are in a life-and-death race the moment they infect a cell.

25 Jan 2023

Study provides an estimate of people in the United States with VEXAS syndrome

About 13,200 men and another 2,300 women in the United States over age 50 are estimated to have VEXAS syndrome, according to a new study led by researchers at NYU Grossman School of Medicine.

24 Jan 2023

Green tea may protect against telomere shortening due to biological aging

A new study in Scientific Reports aimed to analyze the association between cross-section and longitudinal LTL changes with the consumption of soft drinks, coffee, and tea among middle-aged and older Korean men and women for six years. It also assessed any changes in the association results according to a difference in sex and age groups.

11 Jan 2023

Researchers investigate Scandinavian history across 2,000 years

Researchers investigated the history of Scandinavia from the Roman period (between 1.0 CE and 400.0 CE) to the present, spanning over 2,000 years.

10 Jan 2023

SynGAP Research Fund awards $180,000 grant to the University of Edinburgh Medical School's Patrick Wild Centre & Centre for Discovery Brain Sciences

SynGAP Research Fund (SRF), a 501(c)(3) public charity whose mission is to improve the quality of life for SYNGAP1 patients through the research and development of treatments, therapies and support systems, along with SynGAP Research Fund UK, today announced they have awarded a $180,000 grant to the University of Edinburgh Medical School's Patrick Wild Centre & Centre for Discovery Brain Sciences to advance the science around gene transfer to correct SYNGAP1 haploinsufficiency.

5 Jan 2023

Radiation damage to mature sperm cannot be repaired and is instead passed on to the offspring

Whether radiation exposure of fathers can have consequences on their children is one of the most long-standing questions in radiation biology.

21 Dec 2022

Non-invasive artificial intelligence approach for IVF embryo selection

An artificial intelligence algorithm can determine non-invasively, with about 70 percent accuracy, if an in vitro fertilized embryo has a normal or abnormal number of chromosomes, according to a new study from researchers at Weill Cornell Medicine.

20 Dec 2022

First cell-type specific multiomic study of the HIV brain

Researchers identify cell-type-specific differences in HIV integration sites in the brain.

19 Dec 2022

ACMG's new guideline strongly recommends the use of noninvasive prenatal screening for fetal chromosome abnormalities

The American College of Medical Genetics and Genomics (ACMG) has released a new Evidence-Based Clinical Practice Guideline (EBG), "Noninvasive prenatal screening for fetal chromosome abnormalities in a general-risk population: An evidence-based clinical guideline of the American College of Medical Genetics and Genomics."

16 Dec 2022