Linking genetic lineages of giant freshwater prawn Macrobrachium rosenbergii to their global populations

Globally, the giant freshwater prawn Macrobrachium rosenbergii is considered as a commercially important aquaculture species. Genetically, this species is differentiated into western, central and eastern populations. Molecular studies have reported population differences in M. rosenbergii inhabiting Indian waters and have suggested possibilities for the existence of a separate genetic stock in Vembanad Lake (Kerala, S. India). This study was carried out to address this question regarding the lineages of M. rosenbergii inhabiting this lake. Since the lake is divided into ‘downstream’ and ‘upstream’ parts, M. rosenbergii samples were collected from both these regions, and COI sequences were developed. Sequence alignment revealed base substitutions for certain samples, indicating possible population differences. Analysis of molecular variance (AMOVA) also provided a significant Fst value (0.874; p value = 0.00000 ± 0.00000), confirming the population difference in individuals inhabiting the lake. Genetic lineages of these populations towards the global M. rosenbergii populations were investigated using developed and acquired COI sequences for this species. A phylogenetic tree based on neighbor-joining (NJ) analysis and population network revealed the presence of western and central populations in Vembanad Lake. This study recommends identification of natural stocks of M. rosenbergii inhabiting different geographical realms through genetic approaches.