title: Anisakis simplex complex: ecological significance of recombinant genotypes in an allopatric area of the Adriatic Sea inferred by genome-derived simple sequence repeats.
abstract: The genus Anisakis includes nine species which, due to close morphological resemblance even in the adult stage, have previously caused many issues in their correct identification. Recently observed interspecific hybridisation in sympatric areas of two closely related species, Anisakis simplex sensu stricto (s.s.) and Anisakis pegreffii, has raised concerns whether a F1 hybrid generation is capable of overriding the breeding barrier, potentially giving rise to more resistant/pathogenic strains infecting humans. To assess the ecological significance of anisakid genotypes in the Adriatic Sea, an allopatric area for the two above-mentioned species, we analysed data from PCR-RFLP genotyping of the ITS region and the sequence of the cytochrome oxidase 2 (cox2) mtDNA locus to discern the parental genotype and maternal haplotype of the individuals. Furthermore, using in silico genome-wide screening of the A. simplex database for polymorphic simple sequence repeats or microsatellites in non-coding regions, we randomly selected potentially informative loci that were tested and optimised for multiplex PCR. The first panel of microsatellites developed for Anisakis was shown to be highly polymorphic, sensitive and amplified in both A. simplex s.s. and A. pegreffii. It was used to inspect genetic differentiation of individuals showing mito-nuclear mosaicism which is characteristic for both species. The observed low level of intergroup heterozygosity suggests that existing mosaicism is likely a retention of an ancestral polymorphism rather than a recent recombination event. This is also supported by allopatry of pure A. simplex s.s. and A. pegreffii in the geographical area under study.
authors.affiliation: Laboratory of Aquaculture, Institute of Oceanography & Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia. Electronic address: mladineo@izor.hr.
authors.forename: Ivona
authors.initials: I
authors.lastname: Mladineo
authors.affiliation: University Department of Marine Studies, University of Split, Ruđera Boškovića 33, 21000 Split, Croatia.
authors.forename: Željka
authors.initials: Ž
authors.lastname: Trumbić
authors.affiliation: Laboratory of Aquaculture, Institute of Oceanography & Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Radonić
authors.affiliation: Laboratory of Aquaculture, Institute of Oceanography & Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia.
authors.forename: Anamarija
authors.initials: A
authors.lastname: Vrbatović
authors.affiliation: Laboratory of Aquaculture, Institute of Oceanography & Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia.
authors.forename: Jerko
authors.initials: J
authors.lastname: Hrabar
authors.affiliation: Laboratory of Aquaculture, Institute of Oceanography & Fisheries, Šetalište Ivana Meštrovića 63, 21000 Split, Croatia.
authors.forename: Ivana
authors.initials: I
authors.lastname: Bušelić
mesh_terms: D000818:Animals; D017163:Anisakis / Q000145:classification* / Q000235:genetics*; D016000:Cluster Analysis; D051546:Cyclooxygenase 2 / Q000235:genetics; D018509:DNA, Helminth / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D014644:Genetic Variation; D005838:Genotype; D018895:Microsatellite Repeats; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D012150:Polymorphism, Restriction Fragment Length; D011995:Recombination, Genetic; D012623:Seawater / Q000469:parasitology; D017422:Sequence Analysis, DNA
chemical_list: D018509:DNA, Helminth; D021903:DNA, Ribosomal Spacer; D051546:Cyclooxygenase 2
keywords: Adriatic Sea; Anisakis simplex complex; Genetic structure; Recombinant genotypes; Simple sequence repeats