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 develop a machine learning-based screening tool for genetic syndromes in children

With an average accuracy of 88%, a deep learning technology offers rapid genetic screening that could accelerate the diagnosis of genetic syndromes, recommending further investigation or referral to a specialist in seconds, according to a study published in The Lancet Digital Health.

2 Sep 2021

Growing wheat varieties with biological nitrification inhibition trait could increase yields

An international collaboration has discovered and transferred to elite wheat varieties a wild-grass chromosome segment that causes roots to secrete natural inhibitors of nitrification, offering a way to dial back on heavy fertilizer use for wheat and to reduce the crop's nitrogen leakage into waterways and air, while maintaining or raising its productivity and grain quality, says a new report in the Proceedings of the National Academy of Sciences of the United States of America.

2 Sep 2021

Uppsala researchers find solution to long-standing biological search enigma

How the cell can mend broken DNA using another DNA copy as template has puzzled researchers for years. How is it possible to find the correct sequences in the busy interior of the cell? Researchers from Uppsala university have now discovered the solution; it is easier to find a rope than a ball if you are blindfolded.

1 Sep 2021

New, one-stop method developed to avoid de novo genetic disease in embryos

De novo variants (DNVs), genetic mutations that were not previously identifiable in the family history of one of two prospective parents, may cause disease in any children they have.

31 Aug 2021

Research offers new insight into how to treat endometriosis

Endometriosis is a painful, chronic condition in which tissue from the uterus inappropriately grows outside the uterus.

26 Aug 2021

Penn study shows how certain proteins have evolved to suppress cheating chromosomes

Eggs and sperm are special cells for many reasons, but one of the characteristics that sets them apart is that, unlike other human cells, which have two copies of 23 chromosomes, one from the mother and one from the father, these sex cells, or gametes, have only one.

25 Aug 2021

Analysis of seadragon genome offers new insights into its phenotype and sex-determination locus

A study by Prof. LIN Qiang from the South China Sea Institute of Oceanology (SCSIO) of the Chinese Academy of Sciences and his collaborators from Singapore and Germany lifts the veil on seadragons' mysterious looks, and sheds light on a sex-determination locus shared by seadragons and alligator pipefish, both members of the Syngnathidae family.

22 Aug 2021

Study provides insight into fitness effects of genomic structural variants in natural populations

Molecular geneticists have known for about a decade that genomic structural variants can play important roles in the adaptation and speciation of both plants and animals, but their overall influence on the fitness of plant populations is poorly understood.

16 Aug 2021

Structure of BRCA2 protein complex critical for DNA repair solved

The initials BRCA2 may be best known for a gene associated with many cases of breast cancer, and the protein encoded by the BRCA2 gene is critical to repairing breaks in DNA.

13 Aug 2021

Study uncovers epigenetic mechanism that mediates a link between fetal conditions and later health

A study at Tampere University has identified one possible epigenetic mechanism through which the conditions at conception may affect the health of an individual in later life.

10 Aug 2021

SMC protein complex plays a decisive role in the dynamics of holocentromeres

Monocentromeres are typical for the chromosomes of most animals and plants. The centromere is necessary for the transport of the chromosomes and represents the connection point between the chromatids.

6 Aug 2021

Researchers identify genetic markers linked to COVID-19 severity and susceptibility

In collaboration with Northwestern Medicine investigators, an international multi-center study has identified genetic factors associated with SARS-CoV-2 infection and COVID-19 severity, according to findings published in Nature.

6 Aug 2021

Study offers genetic insights into the underlying biology of reproductive aging

The age at which women go through menopause is critical for fertility and impacts healthy ageing in women, but reproductive ageing has been difficult for scientists to study and insights into the underlying biology are limited.

4 Aug 2021

Researchers solve century old mystery by identifying how sex cells get the right genetic mix

A new discovery explains what determines the number and position of genetic exchanges that occur in sex cells, such as pollen and eggs in plants, or sperm and eggs in humans.

3 Aug 2021

In-depth sequencing of SARS-CoV-2 variants crucial in controlling outbreaks

In this interview, News-Medical speaks to Professor Dana Crawford about her research efforts during the COVID-19 pandemic.

2 Aug 2021

Scientists uncover genetics involved in COVID-19 induced respiratory failure

A new genetic study from an international team of scientists has uncovered genes involved in severe coronavirus disease 2019 (COVID-19) illness.

27 Jul 2021

SARS-CoV-2 reprograms host chromatic network to induce immune dysfunction

A recent study conducted at the University of Texas Science Center, Houston, in the USA, has revealed that upon infection, SARS-CoV-2 alters the host chromatin architecture to suppress antiviral interferon-responsive genes and augment inflammatory genes. The study is currently available on the bioRxiv* preprint server.

22 Jul 2021

MET amplification identified as a potentially actionable driver for non-small cell lung cancer

A study led by D. Ross Camidge, MD, PhD, director of thoracic oncology at the University of Colorado School of Medicine and CU Cancer Center member, has helped to define MET amplification as a rare but potentially actionable driver for non-small cell lung cancer (NSCLC).

20 Jul 2021

Transient chromosomal errors can spur the formation of tumors, study finds

A Ludwig Cancer Research study has found that inducing random chromosome instability (CIN) events in mice for as little as one week is enough to trigger harmful chromosomal patterns in cells that spur the formation of tumors.

16 Jul 2021

Researchers discover new genetic driver of autism and other developmental disorders

A research group including Kobe University's Professor TAKUMI Toru (also a Senior Visiting Scientist at RIKEN Center for Biosystems Dynamics Research) and Assistant Professor TAMADA Kota, both of the Physiology Division in the Graduate School of Medicine, has revealed a causal gene (Necdin, NDN) in autism model mice that have the chromosomal abnormality called copy number variation.

9 Jul 2021