Understanding the genomic basis of adaptive response to variable osmotic niches in freshwater prawns: a comparative intraspecific RNA-Seq analysis of Macrobrachium australiense

Understanding the molecular basis of adaptive response to variable environmental conditions is a central goal of evolutionary biology. Here we sought to identify potential outlier SNPs (single nucleotide polymorphisms) in three wild populations of a freshwater prawn (Macrobrachium australiense) that are exposed to differing osmotic niches by using a comparative transcriptomics approach. De novo assembly of approximately 542 million (75 nt) pair end reads collected from 10 individuals revealed 123,396 longer contigs/transcripts of variable length, that showed 97.38% transcriptome assembly completeness. Differential gene expression (DGE) analysis of major osmoregulatory genes revealed that Calreticulin, Na+/H+ exchanger and V-type (H+) ATPase showed the highest expression levels in the Blunder Creek (low ionic) population, while Crustacean cardiovascular peptide (CCP), Na+/K+-ATPase, Na+/K+/2Cl- Co-transporter (NKCC) and Na+/HCO3 exchanger showed the highest expression levels in the Bulim...