Phenotypic selection during laboratory evolution of yeast populations leads to a genome-wide sustainable chromatin compaction shift

ABSTRACT: Based on inheritance of acquired characteristics, Lamarckian theory of evolution explains the evolution of biological systems through epigenetics. In a previous study, we have shown how microbial evolution has resulted in a persistent reduction in expression after repeatedly selecting for the lowest PGAL1-YFP-expressing cells. Applying the ATAC-seq assay on samples collected from this 28-days evolution experiment, here we show how genome-wide chromatin compaction change during evolution under selection pressure. We found that the chromatin compaction was altered not only on GAL network genes directly impacted by the selection pressure, showing an example of non-genetic memory, but also at the whole genome level. The GAL network genes experienced chromatin compaction accompanying the reduction in PGAL1-YFP reporter expression; strikingly, the fraction of global genes with differentially compacted chromatin states accounted for about a quarter of the total genome.  Moreover, some of the ATAC-seq peaks followed well-defined temporal dynamics. Comparing the peak’s intensity in consecutive days, we found most of the differential compaction to occur between days 0 and 3 when the selection pressure was first applied, and between days 7 and 10 when the pressure was lifted. Among the gene sets enriched for the differential compaction events, some had increased chromatin availability once selection pressure was applied and decreased availability after the pressure was lifted (or vice versa). These results intriguingly show that, despite the lack of targeted selection, transcriptional availability of a large fraction of the genome change in a very diverse manner during evolution and these changes can occur in a relatively short number of generations.

ORGANISM(S): Saccharomyces cerevisiae

PROVIDER: GSE205227 | GEO | 2022/09/13

REPOSITORIES: GEO