Population genomics of parasite adaptation: New insights into diversification and speciation of parasites

Masoud NAZARIZADEH DEHKORDI

Doctoral thesis

Abstract:

This thesis investigates the ecological and genetic dynamics of parasitic species, primarily focusing on Ligula intestinalis tapeworms and Cimex bedbugs, aiming to enhance our understanding of their evolutionary biology, genetics, and adaptation mechanisms. In Chapter I, it elucidates the prevalence and population genetic structure of L. intestinalis plerocercoids in various cyprinoid fish species across Czech water bodies, focusing on how different hosts and environments influence genetic diversity and distribution. Chapter II explores the historical dispersal and host-switching events that have shaped the evolutionary history of the L. intestinalis species complex on a global scale. This includes identifying major evolutionary lineages, their host specificity, and the influence of biogeographic and demographic events on lineage diversity. Chapter III provides a highly contiguous genome assembly for L. intestinalis and examines RNA transcription patterns to understand the regulation of biological functions during its life cycle, establishing a comprehensive reference transcriptome for both plerocercoid and adult stages. Chapter IV explores the mechanisms underlying possible ecological speciation in L. intestinalis, particularly under a sympatric setting, to determine whether host specificity influences population structure in the absence of geographical separation. Chapter V shifts focus to the establishment of the tropical bedbug, Cimex hemipterus, in Central Europe, using genetic analyses to reveal limited mtDNA variability and the presence of pyrethroid resistance mutations. Finally, Chapter VI investigates genetic and transcriptomic divergence in C. lectularius populations associated with human and bat hosts, exploring how host switching influences genetic diversity and adaptation. This genomic and transcriptomic approach provides valuable insights into the evolutionary dynamics and adaptive strategies of parasitic species.

Language used: English

Date on which the thesis was submitted / produced: 23. 7. 2024

Thesis defence

• Supervisor: doc. RNDr. Jan Štefka, Ph.D.

UNIVERSITY OF SOUTH BOHEMIA IN ČESKÉ BUDĚJOVICE

Faculty of Science

Doctoral programme / field:
Parazitologie / Parazitologie