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.

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

Genetic determinants of retinol circulation and their impact on health

The genetic architecture of circulating retinol.

15 Aug 2023

UAB researchers identify cell-surface marker that indicates fate of T cells

Follicular helper T cells, or Tfh cells, have a crucial role in immune defense. Without Tfh cells, B cells cannot form germinal center, or GC, responses during which high-affinity antibodies are generated.

14 Aug 2023

New gene therapy shows promise for treating fusion-driven cancers

A new study presents a promising treatment method for so-called fusion-driven cancers, which are currently often difficult to cure. These fusion-driven cancers are caused by an error in cell division that creates a fusion of different genes.

11 Aug 2023

$11 million NIH grant focuses on cognitive function in Down syndrome-associated Alzheimer’s

Neurologist Beau Ances, MD, PhD, talks with his patient, Adam Kloppenberg, who has Down syndrome, at Washington University School of Medicine in St. Louis. People with Down syndrome are at very high risk of developing Alzheimer's disease. Ances is involved in a project led by Jason Hassenstab, PhD, an associate professor of neurology, to develop tools to measure cognitive function in people with Down syndrome-associated Alzheimer's disease.

3 Aug 2023

Genetic variant may explain why some people of African ancestry have lower HIV viral loads

An international team of researchers has found a genetic variant that may explain why some people of African ancestry have naturally lower viral loads of HIV, reducing their risk of transmitting the virus and slowing progress of their own illness.

2 Aug 2023

Study reveals two key mechanisms underlying high risks from lung infections in Down syndrome

Individuals with Down syndrome, the genetic condition caused by triplication of human chromosome 21, also known as trisomy 21, display a very high risk of hospitalization and mortality after developing lung infections.

2 Aug 2023

Phase 1 clinical trial underway to test City of Hope-developed cancer treatment

Researchers at City of Hope, one of the largest cancer research and treatment organizations in the United States, today published a new study explaining how they took a protein once thought to be too challenging for targeted therapy, proliferating cell nuclear antigen (PCNA), and developed a targeted chemotherapy that appears to annihilate all solid tumors in preclinical research.

1 Aug 2023

How do De novo sequencing, QTL mapping, WGS, and lcWGS empower breakthroughs in agrigenomics

Sequencing technology is playing an increasingly important role in agriculture, including crops, livestock and poultry, aquatic organisms, and more.

From MGI 27 Jul 2023

New refget version improves reliability of genomic data analysis

A widely-used tool that finds the exact references needed to pinpoint differences in our DNA just got a refresh.

19 Jul 2023

Study provides new insights into the mechanism of Dmc1 filament assembly

Homologous recombination (HR) is an important process that plays multiple crucial roles during meiosis, a type of cell cycle dedicated to sexual reproduction.

19 Jul 2023

Study reveals immune dysregulation in Down syndrome and potential therapeutic strategy

People with Down syndrome, the condition caused by an extra copy of chromosome 21, or trisomy 21, display chronic dysregulation of their immune system, which can contribute to high rates of autoimmune conditions and severe complications from respiratory infections.

17 Jul 2023

Overdosed gene on chromosome 21 accelerates aging in people with Down's syndrome

An overdosed gene on chromosome 21 causes people with Down's Syndrome to age faster than the general population.

12 Jul 2023

REDH database provides insights into RNA editing in hematopoietic cells

The process of converting DNA to proteins through an RNA is far from straightforward. Of the several types of RNA involved in the process of protein synthesis, a few may be edited mid-way.

10 Jul 2023

PacBio's Revio long-read sequencing system to help Bioscientia solve complex genetic cases

PacBio, a leading developer of high-quality, highly accurate sequencing solutions, today announced that Bioscientia is using its Revio long-read sequencing system to expand its genomics research projects and sequence several thousand human genomes per year.

10 Jul 2023

The Spectrum CE System: A capillary electrophoresis instrument for the forensic laboratory workflow

In this Interview, NewsMedical talks to Ben Krenke about the Spectrum CE system for Forensic laboratory workflow.

From Promega Corporation 7 Jul 2023

Aneuploidy could function as a therapeutic target for cancer

Cancer cells with extra chromosomes depend on those chromosomes for tumor growth, a new Yale study reveals, and eliminating them prevents the cells from forming tumors.

6 Jul 2023

New therapy to mitigate fragile X syndrome may be on the horizon

An antisense therapy developed by Joel D. Richter, PhD, Sneha Shah, PhD, and Jonathan K. Watts, PhD, at UMass Chan Medical School and Elizabeth Berry-Kravis, MD, PhD, at RUSH University Medical Center, restores production of the protein FMRP in cell samples taken from patients with fragile X syndrome.

5 Jul 2023

New AI tool can help track and identify complex fruit fly behavior

How can you tell if a fruit fly is hungry? Ask a computer. While that may sound like a bad dad joke, it's reality at Tulane University, where researchers have developed a new A.I. tool that can tell you if a fruit fly is hungry, sleepy or singing (yes, fruit flies sing).

30 Jun 2023

Scientists visualize dynamic motion of gene regions on chromosomes

Despite being densely packed to fit into the nucleus, chromosomes storing our genetic information are always in motion.

29 Jun 2023