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 (627 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
Either of the two longitudinally adjacent threads formed when a eukaryotic chromosome replicates prior to mitosis. The chromatids are held together at the centromere. Sister chromatids are derived from the same chromosome. (Singleton and Sainsbury, Dictionary of Microbiology and Molecular Biology, 2d 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: Chromatid.
Where it fits in the MeSH classification
- Broader topics
- Chromosome Structures
- See also
- Sister Chromatid Exchange
Research landscape
PubMed indexes 3,370 records tagged with the MeSH heading “Chromatids” (counts retrieved 2026-10-29). 239 of them (7.1%) were published from 2020 onward, and the busiest period so far is through 1999 with 1,785 records.
Reviews account for 311 records (9.2%) and meta-analyses for 0. Randomized controlled trials number 1 (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 | 1,785 |
| 2000-2009 | 703 |
| 2010-2019 | 643 |
| 2020 onward | 239 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 311 | 9.2% |
| Meta-analyses | 0 | 0.0% |
| Randomized controlled trials | 1 | 0.0% |
Method: PubMed query "Chromatids"[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 |
|---|---|---|---|---|
| A Structure-Based Mechanism for DNA Entry into the Cohesin Ring | 2020 | Research article Design not recorded in structured metadata | 148 | cc by PMID 32755595 · DOI · PMC7507959 |
| Establishment of DNA-DNA Interactions by the Cohesin Ring | 2018 | Research article Design not recorded in structured metadata | 138 | cc by PMID 29358048 · DOI · PMC5786502 |
| Sororin actively maintains sister chromatid cohesion | 2016 | Research article Design not recorded in structured metadata | 109 | cc by PMID 26903600 · DOI · PMC4801952 |
| Sororin locks the DNA-exit gate of cohesin to preserve sister-chromatid cohesion | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 41807408 · DOI · PMC12976308 |
A Structure-Based Mechanism for DNA Entry into the Cohesin Ring [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Despite key roles in sister chromatid cohesion and chromosome organization, the mechanism by which cohesin rings are loaded onto DNA is still unknown.
- Closing excerpt
- Our results establish the molecular basis for cohesin loading onto DNA.
- 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 (150 words)
Despite key roles in sister chromatid cohesion and chromosome organization, the mechanism by which cohesin rings are loaded onto DNA is still unknown. Here we combine biochemical approaches and cryoelectron microscopy (cryo-EM) to visualize a cohesin loading intermediate in which DNA is locked between two gates that lead into the cohesin ring. Building on this structural framework, we design experiments to establish the order of events during cohesin loading. In an initial step, DNA traverses an N-terminal kleisin gate that is first opened upon ATP binding and then closed as the cohesin loader locks the DNA against the ATPase gate. ATP hydrolysis will lead to ATPase gate opening to complete DNA entry. Whether DNA loading is successful or results in loop extrusion might be dictated by a conserved kleisin N-terminal tail that guides the DNA through the kleisin gate. Our results establish the molecular basis for cohesin loading onto DNA.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 32755595 · DOI · PMC7507959
Establishment of DNA-DNA Interactions by the Cohesin Ring [2]
Abstract reading summary — source excerpts
- Opening excerpt
- The ring-shaped structural maintenance of chromosome (SMC) complexes are multi-subunit ATPases that topologically encircle DNA.
- Closing excerpt
- Our study illustrates second-DNA capture by an SMC complex and provides a molecular model for the establishment of sister chromatid cohesion.
- 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 (134 words)
The ring-shaped structural maintenance of chromosome (SMC) complexes are multi-subunit ATPases that topologically encircle DNA. SMC rings make vital contributions to numerous chromosomal functions, including mitotic chromosome condensation, sister chromatid cohesion, DNA repair, and transcriptional regulation. They are thought to do so by establishing interactions between more than one DNA. Here, we demonstrate DNA-DNA tethering by the purified fission yeast cohesin complex. DNA-bound cohesin efficiently and topologically captures a second DNA, but only if that is single-stranded DNA (ssDNA). Like initial double-stranded DNA (dsDNA) embrace, second ssDNA capture is ATP-dependent, and it strictly requires the cohesin loader complex. Second-ssDNA capture is relatively labile but is converted into stable dsDNA-dsDNA cohesion through DNA synthesis. Our study illustrates second-DNA capture by an SMC complex and provides a molecular model for the establishment of sister chromatid cohesion.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 29358048 · DOI · PMC5786502
Sororin actively maintains sister chromatid cohesion [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Cohesion between sister chromatids is established during DNA replication but needs to be maintained to enable proper chromosome-spindle attachments in mitosis or meiosis.
- Closing excerpt
- This implies that sororin recruitment to cohesin does not depend on the DNA replication machinery or process itself, but on a property that cohesin acquires during cohesion establishment.
- 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 (174 words)
Cohesion between sister chromatids is established during DNA replication but needs to be maintained to enable proper chromosome-spindle attachments in mitosis or meiosis. Cohesion is mediated by cohesin, but also depends on cohesin acetylation and sororin. Sororin contributes to cohesion by stabilizing cohesin on DNA. Sororin achieves this by inhibiting WAPL, which otherwise releases cohesin from DNA and destroys cohesion. Here we describe mouse models which enable the controlled depletion of sororin by gene deletion or auxin-induced degradation. We show that sororin is essential for embryonic development, cohesion maintenance, and proper chromosome segregation. We further show that the acetyltransferases ESCO1 and ESCO2 are essential for stabilizing cohesin on chromatin, that their only function in this process is to acetylate cohesin's SMC3 subunit, and that DNA replication is also required for stable cohesin-chromatin interactions. Unexpectedly, we find that sororin interacts dynamically with the cohesin complexes it stabilizes. This implies that sororin recruitment to cohesin does not depend on the DNA replication machinery or process itself, but on a property that cohesin acquires during cohesion establishment.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 26903600 · DOI · PMC4801952
Sororin locks the DNA-exit gate of cohesin to preserve sister-chromatid cohesion [4]
Abstract reading summary — source excerpts
- Opening excerpt
- The cohesin complex mediates sister-chromatid cohesion by topologically entrapping DNA within an SMC1-SMC3-RAD21 ring, yet how Sororin preserves cohesion beyond its known role of antagonizing Pds5 binding to the release factor Wapl has remained unclear.
- Closing excerpt
- Together, these findings redefine Sororin as a dual-function regulator that both antagonizes Wapl-Pds5 and directly locks the RAD21-SMC3 exit gate to stabilize sister-chromatid cohesion while permitting its timely dissolution.
- 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 (169 words)
The cohesin complex mediates sister-chromatid cohesion by topologically entrapping DNA within an SMC1-SMC3-RAD21 ring, yet how Sororin preserves cohesion beyond its known role of antagonizing Pds5 binding to the release factor Wapl has remained unclear. Here, we show that the extreme C-terminal region (CTR) of Sororin functions as a direct structural lock for cohesin's DNA-exit gate by engaging the RAD21-SMC3 interface. Centromere-tethered Sororin-CTR fully restores cohesion after Sororin depletion, whereas constitutive chromatin tethering prevents cohesin removal, recapitulating Wapl-loss phenotypes, including impaired mitotic chromosome condensation, decatenation and segregation. Through biochemical reconstitution, AlphaFold3-guided modeling, and targeted mutagenesis, we define conserved hydrophobic and electrostatic contacts between Sororin-CTR and the RAD21-SMC3 gate, the disruption of which abolishes cohesion in a Wapl-dependent manner. Furthermore, mitotic phosphorylation of Sororin selectively disrupts Pds5 binding while leaving gate engagement intact, providing a regulated molecular switch for cohesin release. Together, these findings redefine Sororin as a dual-function regulator that both antagonizes Wapl-Pds5 and directly locks the RAD21-SMC3 exit gate to stabilize sister-chromatid cohesion while permitting its timely dissolution.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41807408 · DOI · PMC12976308
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 Disseminating the genome: joining, resolving, and separating sister chromatids during mitosis and meiosis [5]
- Research article The cohesin complex and its roles in chromosome biology [6]
- Research article Segregating sister genomes: the molecular biology of chromosome separation [7]
- Research article Organization of Chromosomal DNA by SMC Complexes [8]
- Research article Splitting the chromosome: cutting the ties that bind sister chromatids [9]
- Research article Sister chromatid cohesion: a simple concept with a complex reality [10]
References
- Higashi TL, Eickhoff P, Sousa JS, Locke J, Nans A, Flynn HR, et al.. A Structure-Based Mechanism for DNA Entry into the Cohesin Ring. . 2020. PMID 32755595 · DOI · PMC7507959
- Murayama Y, Samora CP, Kurokawa Y, Iwasaki H, Uhlmann F. Establishment of DNA-DNA Interactions by the Cohesin Ring. . 2018. PMID 29358048 · DOI · PMC5786502
- Ladurner R, Kreidl E, Ivanov MP, Ekker H, Idarraga-Amado MH, Busslinger GA, et al.. Sororin actively maintains sister chromatid cohesion. . 2016. PMID 26903600 · DOI · PMC4801952
- Chen Q, Yuan X, Shi M, Zhou X, Zhu S, Lu W, et al.. Sororin locks the DNA-exit gate of cohesin to preserve sister-chromatid cohesion. . 2026. PMID 41807408 · DOI · PMC12976308
- Nasmyth K. Disseminating the genome: joining, resolving, and separating sister chromatids during mitosis and meiosis. Annu Rev Genet. 2001. PMID 11700297 · DOI
- Peters JM, Tedeschi A, Schmitz J. The cohesin complex and its roles in chromosome biology. Genes Dev. 2008. PMID 19056890 · DOI
- Nasmyth K. Segregating sister genomes: the molecular biology of chromosome separation. Science. 2002. PMID 12142526 · DOI
- Yatskevich S, Rhodes J, Nasmyth K. Organization of Chromosomal DNA by SMC Complexes. Annu Rev Genet. 2019. PMID 31577909 · DOI
- Nasmyth K, Peters JM, Uhlmann F. Splitting the chromosome: cutting the ties that bind sister chromatids. Science. 2000. PMID 10827941 · DOI
- Onn I, Heidinger-Pauli JM, Guacci V, Unal E, Koshland DE. Sister chromatid cohesion: a simple concept with a complex reality. Annu Rev Cell Dev Biol. 2008. PMID 18616427 · DOI
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.
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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.