Analyses of molecular markers and gene expression incrustacean species

Abstract

Crustaceans are one of the most diverse groups on the planet. The gooseneck barnacle Pollicipes pollicipes and the common littoral shrimp Palaemon serratus are both vital fishery resources in numerous regions. This PhD thesis aims to contribute to the understanding of these species by analysing the genetic variability and identifying interesting genes. Firstly, the analysis of molecular organisation of the 5S ribosomal DNA (5S rDNA) showed different size variants of 5S rDNA arrays in the genome of the genus Pollicipes. Phylogenetic analyses have shown a pattern of gene clustering among species. These results suggested that the 5S rDNA evolves in the birth and death process. Secondly, transcriptome assemblies were the previous step to gene identification and the quantification of gene expression. In this regard, several transcripts related to larval settlement in barnacles were identified and further evaluated using RT-qPCR. Finally, the analysis of the diversity and the genetic structure of P. serratus revealed that a biogregraphical break was located to the west of the Strait of Gibraltar. For future management of P. serratus we suggested delimiting two different priority areas (Atlántico vs Gibraltar-Meditarráneo) and considering the population of Estuary of Guadalquivir as a separate stock.