Microphallus piriformes (Odhner, 1905)

Repkin, Egor A., Maltseva, Arina L., Varfolomeeva, Marina A., Aianka, Roman V., Mikhailova, Natalia A. & Granovitch, Andrei I., 2020, Genetic and morphological variation of metacercariae of Microphallus piriformes (Trematoda, Microphallidae): Effects of paraxenia and geographic location, International Journal for Parasitology: Parasites and Wildlife 11, pp. 235-245 : 238

3.2. Genetic polymorphism in populations of M. piriformes . COI

COI gene proved to be rather polymorphic in M. piriformes : among 64 samples sequenced we have found 29 different haplotypes of COI fragment; three were observed most often. The Bayesian inference based on COI-sequences ( Fig. 3 ) implies a limited gene flow between populations of the White and Barents Seas, as there are several location-specific clades on the tree, e.g., clades including samples exclusively from ether Korga-islet (White Sea) or Kiberg (Barents Sea).

Strong effect of geographic location on haplotypes distribution is obvious also in the haplotypes network ( Fig. 4A ): although most often haplotypes were detected in all three examined regions, there were also many location-specific haplotypes, including several singletons, clustering according geographic region. As evidenced by both the Bayesian inference ( Fig. 3 ) and haplotypes network ( Fig. 4B ) there was no detectable population subdivision based on host species: haplotypes of M. piriformes parasitizing hosts of different species were interspersed after both analyses.

Figures

Fig. 3. Bayesian inference based on COI sequence (369 bp); 15000000 generation; GTR + I + G substitution model; A posteriori probabilities are indicated by node shapes; sample name includes parasite species (pir – M. piriformes, pyg – M. pygmaeus, tri – M. triangulatus, sim – M. similis), sample number, geographic region and location (WSk – White Sea, Korga-Islet; WSy – White Sea, Yakovleva; DZe – Barents Sea, Dalnie Zelentsy; Kib - Barents Sea, Kiberg; Tro - Norwegian Sea, Tromsø), host species (sax – L. saxatilis; arc – L. arcana; comp – L. compressa; obt – L. obtusata; fab – L. fabalis). Identical haplotypes and the FST-value of differentiation between populations (Weir, and Cockerham, 1984) are shown in Supplementary Table 1. Branch color reflects geographic region.

Fig. 4. Haplotype networks, COI sequence (369 bp); TCS algorithm; dashes correspond to mutations. A: color reflects sampling location. B: color reflects host species.