PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 8933906

Interlaboratory comparison of DNA image analysis.

F B Thunnissen·I O Ellis·U Jütting
View original source ↗Export metadata ↓

Abstract

Interlaboratory quality assurance studies have been conducted for DNA flow cytometry, but not for DNA image analysis systems. The purpose of this study was to investigate if concordance of DNA image analysis systems existed with respect to classification and staining of standardized material. In three separate rounds, human liver cells were measured randomly by means of the image cytometry system present in each participating laboratory. The features integrated optical density (IOD) and AREA were reported. The relationship between the coefficient of variation (CV) of the 2c and 4c peak were compared with three models. In the three rounds the number of participating laboratories was 11, 14 and 11, respectively. Sequential plotting of normalized IOD values yielded useful information about intra-measurement variation. Comparison of measurements in specimens stained in the participating and central laboratory revealed similar CV values. In general, the precision of the instruments, expressed as the 4c/2c and 8c/2c ratios was good. The accuracy of the different laboratories expressed as the CV of IOD for the three rounds varied from 2-17%. The relation of the CVs of the 2c and the 4c peaks was best fit with the model of the addition of two normal distributions. We conclude that interlaboratory comparison of DNA measurements performed on different instruments is certainly feasible and could facilitate improvement in quality standards.

Explore related subjects

DNAHumansImage CytometryLaboratoriesLiverQuality ControlComparative StudyJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

F B Thunnissen, I O Ellis, U Jütting. 1996. Interlaboratory comparison of DNA image analysis.. https://pubmed.ncbi.nlm.nih.gov/8933906/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2026

VIPR RNA-guided DNA recognition by noncontiguous geometric triplex formation.

Viral interference programmable repeat (VIPR) systems use a noncontiguous code for RNA-guided transcriptional silencing. How the Vipr protein and a VIPR RNA (vrRNA) comprising alternating GGY and NN segments achieve precise DNA targeting is unknown. Here, we present 21 cryo-electron microscopy structures that help explain the mechanism of target engagement. Vipr protomers oligomerize along the vrRNA to form a right-handed helical filament, sequestering each GGY motif and positioning the adjacent NN bases for target base pairing. DNA binding, in which every third nucleotide is skipped, results in a gapped vrRNA-DNA hybrid helix that encircles the nontarget DNA strand to form a geometric triplex. These findings suggest that triplex-mediated target-strand handoff could enable noncontiguous and programmable RNA-guided DNA recognition in VIPR systems.

DNA↗
PubMed2026

Caloric restriction modulates genome-wide somatic mutation in mice.

Somatic mutations accumulate throughout life in every cell, and this process constitutes one of the hallmarks of aging-genomic instability. Caloric restriction (CR) has been shown to extend lifespan across diverse species. Using high-fidelity duplex DNA sequencing of bulk liver, bulk kidney, hepatocytes, and cerebellar neurons, we found that CR in mice reduces genome-wide somatic mutation burdens across multiple tissues and cell types. CR reduced both substitution and insertion/deletion burdens, with the magnitude of these effects varying across sample types. CR also decreased the activity of the enigmatic single-base substitution (SBS) mutational process SBS5 that gives rise to most mutations in mammals. Surprisingly, the mutation burden reduction from CR was greatest in transcriptionally inactive regions. This work illuminates links between diet, aging, and genomic integrity and establishes genomic integrity as a modifiable axis of aging.

DNA↗
PubMed2026

Maternal DNA repair safeguards genome stability during the oocyte-to-embryo transition.

De novo mutations are a major source of genetic variation and disease risk, yet the developmental timing and mechanisms underlying their origin require further investigation. While germ cells have traditionally been considered the primary source of these mutations, increasing evidence suggests that a substantial fraction arise after fertilization. Here, we investigated the role of maternal DNA repair in shaping mutagenesis during this critical window by using a mouse model with oocyte-specific disruption of the homologous recombination factor RAD51 and a combination of cellular and molecular analyses. Loss of maternal RAD51 led to the accumulation of DNA double-strand breaks in oocytes without impairing their growth, meiotic maturation, or fertilization competence. In contrast, embryos derived from RAD51-deficient oocytes exhibited increased DNA damage and developmental delay during early cleavage stages. Whole-genome sequencing revealed a significant increase in de novo variants in offspring, the majority displaying intermediate allele frequencies consistent with post-zygotic mosaic mutations. These findings confirm that maternal DNA repair safeguards genome stability across the oocyte-to-embryo transition and identify early embryogenesis as a major source of de novo mutations, with implications for reproductive biology and the origins of genetic diseases.

DNA↗