Chromosome analysis of Phyllodistomum folium (Trematoda, Gorgoderidae) infecting three European populations of zebra mussels

Abstract

The mitotic chromosome sets of the larval stages of Phyllodistomum folium infecting three European populations of Dreissena polymorpha were studied using conventional Giemsa staining and karyometrical analysis. The karyotype, described herein for the first time, consisted of nine chromosome pairs (2 n=18). The chromosomes were comparatively small and measured from 1.19 micro m to 5.22 micro m. The first and second longest chromosome pairs were, respectively, approximately 20% and 18% of the mean total chromosome set length and were clearly differentiated from the other seven pairs, which gradually decreased in size. Most chromosomes were biarmed with medially or submedially located centromeres; only pairs 1 and 4 contained subterminally located centromeres. No significant differences in the relative length values of corresponding chromosomes were observed between the three populations studied. The main interpopulation differences were detected in the centromeric index values of some corresponding chromosome pairs. These data, when analysed in conjunction with those of other Gorgoderidae, indicate that the karyotype of P. folium and other species in this family do not show any clear affinities with "typical" plagiorchiate chromosome sets.

Molecular Cytogenetics in Digenean Parasites: Linked and Unlinked Major and 5S rDNAs, B Chromosomes and Karyotype Diversification

“…; however, this approach has been scarcely applied to Digenea, and chromosome analyses have been performed on only about 300 of the 18,000 described species [Baršiené, 1993;Bell et al, 1998;Petkevičiūtė et al, 2003;Špakulová and Casanova, 2004;Reblánová et al, 2011;Zadesenets et al, 2012a, b;Petkevičiūtė et al, 2012Petkevičiūtė et al, , 2014Petkevičiūtė et al, , 2015Sofi et al, 2015]. Most of them were restricted to the description of diploid chromosome numbers and karyotypes obtained from Giemsa-stained metaphase plates [Baršiené, 1993;Špakulová and Casanova, 2004].…”

Is there a link between shell morphology and parasites of zebra mussels?

“…Parasites were identified following Molloy et al (1997Molloy et al ( , 2001Molloy et al ( , 2005. The two trematode species P. folium and B. polymorphus have been previously described by molecular techniques in French samples (Petkeviči utė et al, 2003;Stunžė nas et al, 2004). Ciliates belong to the genus Ophryoglena.…”