The digenean complex life cycle: phylostratigraphy analysis of the molecular signatures

Abstract

The parasitic flatworms from Digenea group have been the object of numerous in-depth studies for several centuries. The question of the evolutionary origin and transformation of the digenean complex life cycle remains relevant and open due to the biodiversity of these parasites and the absence of fossil records. However, modern technologies and analysis methods allow to get closer to understanding the molecular basis of both the realization of the cycle and its complication. In the present study, we have applied phylostratigraphy and evolutionary transcriptomics approaches to the available digenean genomic and transcriptomic data and built ancestral genomes models. The comparison results of Platyhelminthes and Digenea ancestor genome models made it possible to identify which genes were gained and duplicated in the possible genome of digenean ancestor. Based on the bioprocesses enrichment analysis results, we assumed that the change in the regulation of many processes, including embryogenesis, served as a basis for the complication of the ancestor life cycle. The evolutionary transcriptomics results obtained revealed the “youngest” and “oldest” life cycle stages of Fasciola gigantica, F. hepatica, Psilotrema simillimum, Schistosoma mansoni, Trichobilharzia regenti, and T. szidati. Our results can serve as a basis for a more in-depth study of the molecular signatures of life cycle stages and the evolution transformation of individual organ systems and stage-specific traits.

Expression of Transposable Elements throughout the Fasciola hepatica Trematode Life Cycle

“…RNA-seq data for parthenogenetic stages of F. hepatica are unavailable, making it impossible to determine TE expression levels during this stage. Likewise, significant changes occur during the metacercaria stage, where many processes are activated, including high expression levels of genes related to metabolic activity, cell signaling, DNA replication, and transcription [ 69 , 70 , 71 , 72 ]. Moreover, metacercariae express a set of microRNAs and lncRNAs [ 15 , 31 , 73 ].…”