PhD defence

PhD defence Kasia Rybarczyk

Thesis Title: Phylogenetic relationships within major nematode clades based on multiple molecular markers.


Nematodes are inconspicuous animals that are hardly known to the general public as most individuals are colorless and smaller than 1 mm. To a far lesser extent it is known that majority of nematodes are key players in the soil food web and can be used as indicators for biological condition of the environment they live in.

The thesis focuses on evolutionary relationships within such ecologically important nematodes (orders Dorylaimida and Mononchida) and relations among economically relevant groups of soil nematodes - plant parasitic members of Aphelenchida and Tylenchida. Those relationships are investigated based on sequences from 4 genes: commonly used small and large ribosomal subunits (SSU and LSU rDNA), β-1,4-endoglucanase (cellulase from glycoside hydrolase family 5) and first subunit of the RNA polymerase II (rpb1). Moreover, due to morphological similarities of soil nematodes their identification is problematic. As a solution to this situation a molecular framework for nematode detection and quantification is presented.