Evolution and characterization of carboplatin resistance at single cell resolution

Acquired resistance to carboplatin is a major obstacle to the cure of ovarian cancer, but its molecular underpinnings are still poorly defined. We selected multiple clones derived from a single cell in parallel for similar levels of resistance to carboplatin. The resistant clones showed no significant genetic alterations, but each one activated different mechanisms of resistance resulting in transcriptional heterogeneity. Single-cell mRNA sequencing defined multiple transcriptional states associated with clone identity and resistance evolution, and identified a subset of unselected parental cells that were already in a resistant state. Six expression signatures derived from the resistant states distinguished primary from recurrent high-grade serous ovarian cancers, predicted both response and survival and disclosed functional differences between intrinsic and acquired resistance. This multidimensional, single-cell analysis offers new insights into the dynamics of the acquisition of resistance to carboplatin, a drug of major importance to the treatment of ovarian and other cancers.

Analysis of the genetic structure of a model Scots pine (Pinus sylvestris) seed orchard for development of management strategies

Genetic structure, diversity and clonal homogeneity were determined on the basis of the isozyme gene markers in a model Scots pine seed orchard in the north-eastern part of the Czech Republic that originated from natural forest regions NFR 28 and 29 (Jeseníky Mts.) and the 2^nd and 3^rd forest altitudinal zones (FAZ). Clone and ramet crop variation for the 2009–2011 period was assessed. Comparing the loci measured also in two pine orchards in central Slovakia, a similar proportion of homogeneous clones but considerably lower expected heterozygosity were found out for most of the measured isozyme loci. Heterozygosity of the investigated orchard did not change considerably after the exclusion of alien and wrongly placed ramets. No difference in average cone production between clones originating from different NFR was observed. Verification of the clone identity of seed orchards managed in a certain way can be suggested with the subsequent removal of alien ramets.