Cytogenetic and molecular analyses in "Palaemon" species

Abstract

In this PhD thesis, different genetic studies were carried out in two marine species of the genus Palaemon Weber, 1795 (Crustacea, Decapoda): the common littoral prawn Palaemon serratus (Pennant, 1777) and the rockpool prawn Palaemon elegans Rathke, 1837. Both their European distribution and morphological similarity make them interesting candidate species for developing population and cytogenetic analyses, complementing phylogenetic studies in order to clarify the evolution of the genus Palaemon. Furthermore, given the commercial relevance of P. serratus, this thesis aims to contribute to the effective management and traceability of this natural resource. Firstly, we applied cytogenetic analyses based on conventional staining, banding techniques and fluorescence in situ hybridisation to identify and characterise these two prawn species. The results obtained from this study revealed a high degree of diversity in chromosome number, karyotype and sex determination system, ranging from the putative absence of heteromorphic sex chromosomes to the multiple chromosome system X1X1X2X2/X1X2Y. Afterwards, we carried out a phylogeographic analysis of P. serratus to test intraspecific genetic diversity and geographic structure. A pronounced genetic differentiation was detected between Mediterranean and Atlantic populations and an uncommon phylogeographic boundary was unveiled. Finally, we developed a species-specific PCR-assay as a traceability tool for authentication of P. serratus and other four economically important prawn species.