Higher-order epistasis shapes natural variation in germ stem cell niche activity

Abstract

To study how natural allelic variation explains quantitative developmental system variation, we characterized natural differences in germ stem cell niche activity, measured as progenitor zone (PZ) size, between two Caenorhabditis elegans isolates. Linkage mapping yielded candidate loci on chromosomes II and V, and we found that the isolate with a smaller PZ size harbours a 148 bp promoter deletion in the Notch ligand, lag-2/Delta, a central signal promoting germ stem cell fate. As predicted, introducing this deletion into the isolate with a large PZ resulted in a smaller PZ size. Unexpectedly, restoring the deleted ancestral sequence in the isolate with a smaller PZ did not increase—but instead further reduced—PZ size. These seemingly contradictory phenotypic effects are explained by epistatic interactions between the lag-2/Delta promoter, the chromosome II locus, and additional background loci. These results provide first insights into the quantitative genetic architecture regulating an animal stem cell system.

Military Activity Impact on Vegetation in Pannonian Dry Sandy Grasslands

“…sample area tolerated the active military activities well. The role of the dominant species in the open sandy grasslands (Festuca vaginata and the endemic Festuca pseudovaginata) might be enhanced by this condition, as endemic species can adapt better to climate change [59][60][61][62][63]. Based on our study, we were able to confirm that these endemic, extreme-drought-tolerant, perennial Festuca species and the studied vegetation types were well adapted to extreme drought and tolerated the extreme human disturbance, with changes in soil and climate in the micro-conditions.…”

Aging disrupts spatiotemporal regulation of germline stem cells and niche integrity

“…The progenitor zone extent was assessed by measuring from the most distal end of the gonad to the end of the progenitor zone using a segmented line on ImageJ to consider the natural curve of the gonad. The boundary of the progenitor zone was determined by the presence of more than one cell presenting a crescent-shaped morphology ( Byrd et al, 2014 ; Crittenden et al, 2006 ; Fausett et al, 2023 ; Gordon, 2020 ; Roy et al, 2016 ).…”

Analysis of multiple programmed cell death-related prognostic genes and functional validations of necroptosis-associated genes in oesophageal squamous cell carcinoma

“…Recall curves were evaluated to assess the precision and recall of the model based on the “modEvA” R package. 59 Correlations between variables were examined using Pearson correlation analysis. Immune cell levels and the immune score of samples were evaluated using “CIBERSORT” and ESTIMATE” R packages and “TIMER 2.0” website”.…”