Transcriptomic isolation and sequencing of the freshwater mussel Anodonta anatina : A pilot study and method development

Abstract: The freshwater mussel Anodonta anatina is a common mollusc found in rivers and lakes in Europe. Due to its lifestyle as an immobile substrate filter feeder, it is only exposed to pollutions which passes by it, thus the mussels are viable to be used as a bioindicator for the analysis of local aquatic health. With the recent decades of advancements in nucleotide sequencing platforms, transcriptomic analysis could be utilized to make an assessment of the quality of water, as the transcriptome of organisms respond to the presence of toxins and changes in the environment. The aim of this project was to develop a method to isolate and sequence the transcriptome of the hepatopancreas of the freshwater mussel A. anatina with an Oxford MinION nanopore sequencer. The method used two samples collected from a previous study where one mussel, named “unexposed sample 05H” for this thesis, was used as a control while the second sample, named “exposed sample 08H”, was exposed to 100 μg Cu2+/L. The method processed 80 mg of hepatopancreatic tissue and measured a 99.7 % drop in RNA during the five different protocols utilized. The method produced viable data, and the web based bioinformatic program NanoPipe managed to identify homologous sequences to the genome of the Mediterranean mussel Mytilus galloprovincialis. Due to a low number of samples, no comparative study of coppers effect on the transcriptome could be made.