Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 4 complete abstracts (798 words), 10 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
The homologous chromosomes that are dissimilar in the heterogametic sex. There are the X chromosome, the Y chromosome, and the W, Z chromosomes (in animals in which the female is the heterogametic sex (the silkworm moth Bombyx mori, for example)). In such cases the W chromosome is the female-determining and the male is ZZ. (From King and Stansfield, A Dictionary of Genetics, 4th ed)
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Chromosome, Sex; Chromosomes, Sex; Sex Chromosome; Gonosomes; Gonosome.
Where it fits in the MeSH classification
- Broader topics
- Chromosomes
- Narrower topics
- Pseudoautosomal Regions; Sex Chromatin; X Chromosome; Y Chromosome
Related concepts
Research landscape
PubMed indexes 45,409 records tagged with the MeSH heading “Sex Chromosomes” (counts retrieved 2026-10-29). 3,579 of them (7.9%) were published from 2020 onward, and the busiest period so far is through 1999 with 24,272 records.
Reviews account for 4,532 records (10.0%) and meta-analyses for 58. Randomized controlled trials number 20 (0.0%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 24,272 |
| 2000-2009 | 10,261 |
| 2010-2019 | 7,297 |
| 2020 onward | 3,579 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 4,532 | 10.0% |
| Meta-analyses | 58 | 0.1% |
| Randomized controlled trials | 20 | 0.0% |
Method: PubMed query "Sex Chromosomes"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in genetics and genomics
Genetic findings vary widely in strength. A variant linked to a condition in one study may not replicate in other ancestries, and most common variants have small effects that are meaningful only in aggregate. Studies of rare, high-impact variants can support strong causal claims about a gene, while association studies describe statistical links that need functional and independent replication. Check the sample size, the ancestry of participants, whether results were replicated, and whether a laboratory or clinical outcome was actually measured.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Aging activates escape of the silent X chromosome in the female mouse hippocampus | 2025 | Research article Design not recorded in structured metadata | 44 | cc by PMID 40043106 · DOI · PMC11881916 |
| A Y chromosome-linked genome editor for efficient population suppression in the malaria vector Anopheles gambiae | 2025 | Research article Design not recorded in structured metadata | 30 | cc by PMID 39747012 · DOI · PMC11696527 |
| Mosaic loss of Y chromosome and mortality after coronary angiography | 2025 | Research article Design not recorded in structured metadata | 26 | cc by PMID 39935193 · DOI · PMC12046225 |
| The X Factor in Immunity: Sex Differences Shaped by the X Chromosome | 2026 | Review article Design not recorded in structured metadata | 10 | cc by PMID 41574968 · DOI · PMC12829307 |
Aging activates escape of the silent X chromosome in the female mouse hippocampus [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Women live longer than men and exhibit less cognitive aging.
- Closing excerpt
- Understanding how the Xi may confer female advantage could lead to novel targets that counter brain aging and disease in both sexes.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (160 words)
Women live longer than men and exhibit less cognitive aging. The X chromosome contributes to sex differences, as females harbor an inactive X (Xi) and active X (Xa), in contrast to males with only an Xa. Thus, reactivation of silent Xi genes may contribute to sex differences. We use allele-specific, single-nucleus RNA sequencing to show that aging remodels transcription of the Xi and Xa across hippocampal cell types. Aging preferentially changed gene expression on the X's relative to autosomes. Select genes on the Xi underwent activation, with new escape across cells including in the dentate gyrus, critical to learning and memory. Expression of the Xi escapee Plp1, a myelin component, was increased in the aging hippocampus of female mice and parahippocampus of women. AAV-mediated Plp1 elevation in the dentate gyrus of aging male and female mice improved cognition. Understanding how the Xi may confer female advantage could lead to novel targets that counter brain aging and disease in both sexes.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 40043106 · DOI · PMC11881916
A Y chromosome-linked genome editor for efficient population suppression in the malaria vector Anopheles gambiae [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Genetic control - the deliberate introduction of genetic traits to control a pest or vector population - offers a powerful tool to augment conventional mosquito control tools that have been successful in reducing malaria burden but that are compromised by a range of operational challenges.
- Closing excerpt
- Mathematical modelling shows that this YLE technology is up to seven times more efficient for population suppression than optimal versions of other self-limiting strategies, such as the widely used Sterile Insect Technique or the Release of Insects carrying a Dominant Lethal gene.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (190 words)
Genetic control - the deliberate introduction of genetic traits to control a pest or vector population - offers a powerful tool to augment conventional mosquito control tools that have been successful in reducing malaria burden but that are compromised by a range of operational challenges. Self-sustaining genetic control strategies have shown great potential in laboratory settings, but hesitancy due to their invasive and persistent nature may delay their implementation. Here, instead, we describe a self-limiting strategy, designed to have geographically and temporally restricted effect, based on a Y chromosome-linked genome editor (YLE). The YLE comprises a CRISPR-Cas9 construct that is always inherited by males yet generates an autosomal dominant mutation that is transmitted to over 90% of the offspring and results in female-specific sterility. To our knowledge, our system represents a pioneering approach in the engineering of the Y chromosome to generate a genetic control strain for mosquitoes. Mathematical modelling shows that this YLE technology is up to seven times more efficient for population suppression than optimal versions of other self-limiting strategies, such as the widely used Sterile Insect Technique or the Release of Insects carrying a Dominant Lethal gene.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 39747012 · DOI · PMC11696527
Mosaic loss of Y chromosome and mortality after coronary angiography [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Background and aimsAcquired somatic mutations emerged as important drivers of adverse cardiovascular disease outcomes.
- Closing excerpt
- Targeting LOY may represent a sex-specific personalized medicine approach.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (294 words)
Background and aimsAcquired somatic mutations emerged as important drivers of adverse cardiovascular disease outcomes. Recently, mosaic loss of Y chromosome (LOY) in haematopoietic cells was identified to induce diffuse cardiac fibrosis in male mice. The aim of the present study was to determine the association between LOY and cardiovascular mortality in patients undergoing coronary angiography.MethodsLOY was quantified in 1698 male participants of the LURIC study, who underwent coronary angiography, and its association with all-cause and cardiovascular mortality was determined. Furthermore, the interaction between LOY and inherited genetic susceptibility for cardiac fibrosis was assessed.ResultsThe frequency of LOY steeply increased in male participants of LURIC at the age of 60 years. Loss of Y chromosome > 17% was associated with significantly higher all-cause [hazard ratio (HR) 1.41, 95% confidence interval (CI) 1.09-1.82] and cardiovascular mortality (HR 1.49, 95% CI 1.09-2.03), which was driven by a higher risk for fatal myocardial infarction (HR 2.65, 95% CI 1.46-4.81). Loss of Y chromosome > 17% was associated with a profibrotic and proinflammatory plasma protein expression profile as characterized by higher plasma levels of osteoprotegerin, matrix metalloproteinase-12, growth differentiation factor 15, heparin-binding EGF-like growth factor, and resistin. Genetic predisposition for lower myocardial fibrosis attenuated the association between LOY and cardiovascular mortality. Genome-wide methylation analyses identified differential methylation in 298 genes including ACTB, RPS5, WDR1, CD151, and ARAP1. Single-cell RNA sequencing further confirmed differential gene expression of 37 of these genes in LOY in peripheral blood mononuclear cells comprising a set of fibrosis-regulating genes including RPS5. RPS5 silencing in macrophages induced a paracrine induction of collagen expression in cardiac fibroblasts documenting a functional role in vitro.ConclusionsLOY represents an important independent risk factor for cardiovascular mortality in male patients with coronary artery disease. Targeting LOY may represent a sex-specific personalized medicine approach.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 39935193 · DOI · PMC12046225
The X Factor in Immunity: Sex Differences Shaped by the X Chromosome [4]
Abstract reading summary — source excerpts
- Opening excerpt
- There are sex differences with immune responses where females exhibit stronger immune responses compared to males.
- Closing excerpt
- We also highlight some dosage-sensitive X-linked genes involved in female-biased autoimmune disease, discuss sex differences with immune signaling pathways, and sex differences with viral infections and vaccine responses with the ultimate goal to leverage these insights for the development of sex-specific therapeutic interventions for immune-related diseases.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (154 words)
There are sex differences with immune responses where females exhibit stronger immune responses compared to males. Both sex hormones and sex chromosome differences between males and females contribute to the observed sex differences with innate and adaptive immune cell composition and function. Here, we present recent findings investigating sex differences with immune cells and responses, highlighting contributions from sex hormones or X-linked genes. We also review the epigenetic gene regulatory mechanisms that form the inactive X chromosome (Xi), known as X-Chromosome Inactivation (XCI), the heterochromatic nature of the Xi that allows for selective gene reactivation, and recent work investigating the mechanisms of XCI maintenance in female immune cells. We also highlight some dosage-sensitive X-linked genes involved in female-biased autoimmune disease, discuss sex differences with immune signaling pathways, and sex differences with viral infections and vaccine responses with the ultimate goal to leverage these insights for the development of sex-specific therapeutic interventions for immune-related diseases.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41574968 · DOI · PMC12829307
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article The X chromosome and sex-specific effects in infectious disease susceptibility [5]
- Research article The X chromosome and immune associated genes [6]
- Research article Sex Hormones and Sex Chromosomes Cause Sex Differences in the Development of Cardiovascular Diseases [7]
- Research article Punctuated bursts in human male demography inferred from 1,244 worldwide Y-chromosome sequences [8]
- Research article X chromosome regulation: diverse patterns in development, tissues and disease [9]
- Research article Forensic use of Y-chromosome DNA: a general overview [10]
References
- Gadek M, Shaw CK, Abdulai-Saiku S, Saloner R, Marino F, Wang D, et al.. Aging activates escape of the silent X chromosome in the female mouse hippocampus. . 2025. PMID 40043106 · DOI · PMC11881916
- Tolosana I, Willis K, Gribble M, Phillimore L, Burt A, Nolan T, et al.. A Y chromosome-linked genome editor for efficient population suppression in the malaria vector Anopheles gambiae. . 2025. PMID 39747012 · DOI · PMC11696527
- Weyrich M, Zewinger S, Sarakpi T, Rasper T, Kleber ME, Cremer S, et al.. Mosaic loss of Y chromosome and mortality after coronary angiography. . 2025. PMID 39935193 · DOI · PMC12046225
- Radovanovic KB, Wynalda M, Anguera MC, Anguera MC. The X Factor in Immunity: Sex Differences Shaped by the X Chromosome. . 2026. PMID 41574968 · DOI · PMC12829307
- Schurz H, Salie M, Tromp G, Hoal EG, Kinnear CJ, Möller M. The X chromosome and sex-specific effects in infectious disease susceptibility. Hum Genomics. 2019. PMID 30621780 · DOI · PMC6325731
- Bianchi I, Lleo A, Gershwin ME, Invernizzi P. The X chromosome and immune associated genes. J Autoimmun. 2012. PMID 22178198 · DOI
- Arnold AP, Cassis LA, Eghbali M, Reue K, Sandberg K. Sex Hormones and Sex Chromosomes Cause Sex Differences in the Development of Cardiovascular Diseases. Arterioscler Thromb Vasc Biol. 2017. PMID 28279969 · DOI · PMC5437981
- Poznik GD, Xue Y, Mendez FL, Willems TF, Massaia A, Wilson Sayres MA, et al.. Punctuated bursts in human male demography inferred from 1,244 worldwide Y-chromosome sequences. Nat Genet. 2016. PMID 27111036 · DOI · PMC4884158
- Deng X, Berletch JB, Nguyen DK, Disteche CM. X chromosome regulation: diverse patterns in development, tissues and disease. Nat Rev Genet. 2014. PMID 24733023 · DOI · PMC4117651
- Kayser M. Forensic use of Y-chromosome DNA: a general overview. Hum Genet. 2017. PMID 28315050 · DOI · PMC5418305
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
See how EvidenceLib is built. Spotted an error? Email support@evidencehelix.com.
Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.