PhD defence and trial lecture: Likith Reddy Pinninti

Thesis title​​​:

Biosystematics and evolutionary genomics of deep-sea fish (lumpsuckers, snailfishes, and sculpins) (Perciformes: Cottoidei)

Trial lecture topic:

The use of lumpfish as cleanerfish in aquaculture: status, challenges, and future perspectives

Evaluation Committee​:

• Professor Albert Kjartan Dagbjartarson Imsland, University of Bergen / R&D Manager, Akvaplan-niva, Iceland
• Professor Samuel A. M. Martin, School of Biological Sciences, Aberdeen University, Scotland
• Associate Professor Vigdis Tverberg, Nord University

Supervisory Committee:

• Main supervisor: Professor Leslie Noble, Nord University
• Co-supervisor: Professor Jorge Fernandes, Nord University
• Co-supervisor: Associate Professor Torstein Kristensen, Nord University
  

About the thesis:

Deep-sea fishes of the Cottoidei (Teleostei: Perciformes) have developed unique adaptations for survival in the deep ocean, yet they remain poorly understood. This thesis used genomic-based approaches to elucidate their adaptation, systematics, and behaviour. Using the PacBio long-read approach, the mitogenome of the Atlantic spiny lumpsucker was sequenced, and additionally, low-coverage genomes were generated for six genomes of deep-sea fishes (Cyclopteridae and Liparidae), with species trees constructed at the single locus and at the multilocus level to understand the evolutionary relationships. Patterns of positive selection were detected in the key genes involved in adipogenesis, DNA repair, and translation, which control fundamental biological functions in deep-sea fish. Lastly, gene expression analysis was used to investigate the role of noradrenaline in the complex social behaviour of cleaner fish and clients. Correlation analysis identified genes associated with locomotion, serotonin, and pigmentation.

This dissertation highlights the utility of genomic approaches in the study of deep-sea fish taxonomy and systematics, evolution, and mutualistic behaviour.