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.

Hyperbaric oxygen treatments in healthy adults can reverse the aging process, finds study

A new study from Tel Aviv University and the Shamir Medical Center in Israel indicates that hyperbaric oxygen treatments (HBOT) in healthy aging adults can stop the aging of blood cells and reverse the aging process.

19 Nov 2020

Men and women may require different brain tumor therapy, study finds

The current study shows that the sex differences in the tumor phenotype vary with the effect of the enhancer regulatory molecule bound to Brd4 on the course of stem cell-like differentiation in male and female GBM cells. Inhibition of Brd4 by genetic and pharmacological factors also varies in males and females, both in vivo and in vitro.

11 Nov 2020

Host genetic "super-variants" may increase COVID-19 death risk

Researchers at Yale University have identified genetic variants among people of white British ancestry that may increase the risk of dying from coronavirus disease 2019 (COVID-19) – the illness caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

11 Nov 2020

Genetic mutation may accelerate heart function decline in DMD patients

A mutation in the gene that causes cystic fibrosis may accelerate heart function decline in those with Duchenne muscular dystrophy (DMD), a new study by UT Southwestern researchers suggests.

4 Nov 2020

Study sheds new light on cell division fidelity, can impact future regenerative medicine

Researchers discover that a specialized part of the chromosomes, essential for a correct cell division, is smaller and weaker in stem cells, when compared to the ones of differentiated cells.

29 Oct 2020

UVA research sheds light on how cancer remodels our chromosomes

Cancer remodels the architecture of our chromosomes so the disease can take hold and spread, researchers at the University of Virginia have revealed.

27 Oct 2020

Study finds new transposon-derived genes related to autism

The lack of some genes in the BEC/TCEAL cluster could be related to some alterations associated with the autism spectrum disorder, according to a preclinical study published in the journal Genome Biology, and led by Professor Jordi Garcia Fernàndez, from the Faculty of Biology and the Institute of Biomedicine of the University of Barcelona, and researcher Jaime Carvajal, from the Andalusian Centre for Developmental Biology - University Pablo de Olavide.

27 Oct 2020

Researchers find a new therapeutic approach to combat leukemia

Leukemia frequently originates from the so-called leukemic stem cell, which resides in a tumor promoting and protecting niche within the bone marrow. Scientists from the Max Planck Institute of Biochemistry in Martinsried, Germany, have found a new way to make these cells vulnerable by specifically dislodging these cells from their niches.

23 Oct 2020

$109 million NIH grant awarded to expand Alzheimer's disease and Down syndrome research

The Alzheimer's Biomarkers Consortium - Down Syndrome, a multi-institution research team, co-led by members from the University of California, Irvine, has been awarded an unprecedented five-year, $109 million grant by the National Institutes of Health, to expand research on the biomarkers of Alzheimer's disease in adults with Down syndrome.

22 Oct 2020

Distinct DNA methylation signature found in the cord blood of newborns diagnosed with ASD

A new study led by UC Davis MIND Institute researchers found a distinct DNA methylation signature in the cord blood of newborns who were eventually diagnosed with autism spectrum disorder (ASD).

22 Oct 2020

Scientists show why zebra finches have problems with reproduction

In birds and other species alike, pairs can face considerable difficulties with reproduction. Scientists at the Max Planck Institute for Ornithology in Seewiesen have now shown in an extensive analysis of 23,000 zebra finch eggs that infertility is mainly due to males, while high embryo mortality is more a problem of the females.

20 Oct 2020

Genomic analysis of neuroblastoma sheds light on childhood solid tumors

Researchers have used insight from a comprehensive genomic analysis of neuroblastoma to learn about the process driving one of the most common childhood solid tumors. The findings revealed possible approaches for developing precision medicines to improve patient outcomes. St. Jude Children's Research Hospital scientists led the study, which appears today in the journal Nature Communications.

15 Oct 2020

People born with a heart defect have low risk of moderate or severe COVID-19 infection

Results of a retrospective analysis suggest that people born with a heart defect who developed COVID-19 symptoms had a low risk of moderate or severe COVID-19 infection, according to a new article published today in the Journal of the American Heart Association, an open access journal of the American Heart Association.

14 Oct 2020

Genomic study shows the evolutionary history of banyan trees and their wasp pollinators

The banyan fig tree Ficus microcarpa is famous for its aerial roots, which sprout from branches and eventually reach the soil.

9 Oct 2020

Excess genetic exchanges impede the segregation of chromosomes into eggs

The exchange of DNA between chromosomes during the early formation of sperm and egg cells normally is limited to assure fertility.

8 Oct 2020

Plasma ABO protein is a causal risk factor for severe COVID-19

Researchers used an integrative genomics approach to find the genes responsible for COVID-19 and its severity.

7 Oct 2020

Researchers decipher evolution of the Y chromosome in great apes

New analysis of the DNA sequence of the male-specific Y chromosomes from all living species of the great ape family helps to clarify our understanding of how this enigmatic chromosome evolved.

6 Oct 2020

Cancer mutations are found in distinct regions that vary based on genomic structure and mutation

A new study from researchers at The University of Texas MD Anderson Cancer Center has discovered that mutations found in cancers do not accumulate randomly, but are found in distinct patterns that vary based on the three-dimensional organization of the genome in the cell as well as the underlying factors causing the mutations

6 Oct 2020

First biobank in Australia for chromosome 15 disorders

The first biobank in Australia aiming to improve research and treatments into rare genetic diseases caused by changes to genes on chromosome 15, including Prader-Willi Syndrome and Angelman Syndrome, will be established at the Murdoch Children's Research Institute.

5 Oct 2020

Genetic heritage from Neanderthals linked to severe COVID-19

Since first appearing in late 2019, the novel virus, SARS-CoV-2, has had a range of impacts on those it infects. Some people become severely ill with COVID-19, the disease caused by the virus, and require hospitalization, whereas others have mild symptoms or are even asymptomatic.

30 Sep 2020