Temporal Stability Evaluation of Population Structure of Blue Mussel (Mytilus chilensis) in Southern Chile Using SNP Markers

Blue mussel aquaculture is an important economic activity in southern Chile, where landings are mainly exported to the European Union. This market has specific labeling regulations about traceability including the obligation to declare the area where the product was caught or farmed. Mussel populations in southern Chile have been thought to be panmictic with limited genetic structure (F_ST < 0.05) due to long-lived pelagic larvae and the translocation of seeds from natural banks to aquaculture farms. This challenging scenario for traceability can be overcome using multiple panels of F_ST outlier SNP loci, which has identified hidden population structure (F_ST > 0.10) not previously revealed with SSR markers. Here we used a combined panel of 172 SNP markers: 48 obtained from published EST and 124 obtained de novo from RADseq (58 F_ST outlier loci and 66 putatively neutral loci). Our goal was to study the temporal stability of population structure from six locations in three zones in southern Chile: Reloncaví Gulf, Chiloe Island and Magallanes in years 2009 and 2013. SNP genotyping was performed using the Genotyping-in-Thousands by sequencing (GT-seq) approach. We discuss the stability of population structure and its implication in molecular traceability of this important commercial resource.

Grant Fondecyt Regular 1130302