The intron 2 of p26 gene: a novel genetic marker for discriminating the two most commercially important Artemia franciscana subspecies

Artemia franciscana is considered as a “superspecies”, since its populations exhibit the highest level of phenotypic plasticity among Artemia species, display high inter-population genetic divergence and/or significant genetic sub-structuring and occur in a broad repertoire of habitats. Encysted embryos originating from two of the most abundant populations (Great Salt Lake – GSL, Utah, USA and San Francisco Bay – SFB, USA) are extensively used in aquaculture industry; these two populations are considered as two subspecies. In this study, we present a novel genetic marker (the second intron of p26 gene) for discriminating GSL and SFB populations. The evaluation of the utility of this marker was achieved by PCR amplification (51 individuals from GSL and 48 individuals from SFB) and sequencing while its mode of inheritance was assessed by 20 reciprocal cross-breeding tests. Results showed that SFB A. franciscana population presented only one pattern (length of PCR amplified fragment was ~1500 bp) while the GSL population showed two patterns; the first showed only one PCR amplified fragment (~2000 bp), while the second presented two bands (at ~2000 bp and ~1500 bp). BLAST searches confirmed the identity of the obtained sequences while the alignment revealed that the observed length variation was mainly attributed to a single insertion of ~400 bp long. The intron 2 of p26 gene follows the Mendelian mode of inheritance, since the expected ratios do not differ significantly from the observed ones (¯ 2 test, p > 0.05). The proposed marker was found to be an effective and practical tool (in terms of high speed, reduced cost and low complexity) to discriminate the two A. franciscana populations / subspecies (GSL and SFB). This marker may be applied in aquaculture industry, molecular ecology and/or other fields of applied research.